200 ? "200px" : this.width)!important;}
-->
介绍
MHA（Master High Availability）目前在MySQL高可用方面是一个相对成熟的解决方案，是一套优秀的作为MySQL高可用性环境下故障切换和主从提升的高可用软件。在MySQL故障切换过程中，MHA能做到在0~30秒之内自动完成数据库的故障切换操作，并且在进行故障切换的过程中，MHA能在最大程度上保证数据的一致性，以达到真正意义上的高可用。它由两部分组成：MHA Manager（管理节点）和MHA Node（数据节点）。MHA Manager可以单独部署在一台独立的机器上管理多个master-slave集群，也可以部署在一台slave节点上。MHA Node运行在每台MySQL服务器上，MHA Manager会定时探测集群中的master节点，当master出现故障时，它可以自动将最新数据的slave提升为新的master，然后将所有其他的slave重新指向新的master。整个故障转移过程对应用程序完全透明。在MHA自动故障切换过程中，MHA试图从宕机的主服务器上保存二进制日志，最大程度的保证数据的不丢失，但这并不总是可行的。例如，如果主服务器硬件故障或无法通过ssh访问，MHA没法保存二进制日志，只进行故障转移而丢失了最新的数据。使用MySQL 5.5的半同步复制，可以大大降低数据丢失的风险。MHA可以与半同步复制结合起来。如果只有一个slave已经收到了最新的二进制日志，MHA可以将最新的二进制日志应用于其他所有的slave服务器上，因此可以保证所有节点的数据一致性。
原理
（1）从宕机崩溃的master保存二进制日志事件（binlog events）;
（2）识别含有最新更新的slave；
（3）应用差异的中继日志（relay log）到其他的slave；
（4）应用从master保存的二进制日志事件（binlog events）；
（5）提升一个slave为新的master；
（6）使其他的slave连接新的master进行复制；
MHA软件由两部分组成，Manager工具包和Node工具包
Manager工具包主要包括以下几个工具：
masterha_check_ssh 检查MHA的SSH配置状况 masterha_check_repl 检查MySQL复制状况 masterha_manger 启动MHA masterha_check_status 检测当前MHA运行状态 masterha_master_monitor 检测master是否宕机 masterha_master_switch 控制故障转移（自动或者手动） masterha_conf_host 添加或删除配置的server信息
Node工具包（这些工具通常由MHA Manager的脚本触发，无需人为操作）主要包括以下几个工具：
save_binary_logs 保存和复制master的二进制日志 apply_diff_relay_logs 识别差异的中继日志事件并将其差异的事件应用于其他的slave filter_mysqlbinlog 去除不必要的ROLLBACK事件（MHA已不再使用这个工具） purge_relay_logs 清除中继日志（不会阻塞SQL线程）
一、安装MHA
1.创建安装目录
Node服务器安装
mkdir -p /usr/local/mha
manage服务器安装
mkdir -p /usr/local/mha/ha1/fail_script
mkdir -p /usr/local/mha/ha1/workdir
/usr/local/mha：程序安装目录
/usr/local/mha/ha1:用于区别每一个mha方案，当前方案ha1
/usr/local/mha/ha1/fail_script：方案ha1的failover脚本保存路径
/usr/local/mha/ha1/workdir:方案ha1的的日志和failover产生的binlog保存路径
2.安装epel插件
使用yum方式安装，需要安装epel源
epel源
wget http://mirrors.ustc.edu.cn/fedora/epel/6/x86_64/epel-release-6-8.noarch.rpm
所有服务器都安装(mananage需要安装以下所有插件,node节点只需要安装perl-DBD-MySQL,cpan)
yum install -y perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-Parallel-ForkManager perl-Time-HiRes cpan
也可以使用perl方式安装
#!/bin/bash
wget http://xrl.us/cpanm --no-check-certificate
mv cpanm /usr/bin
chmod 755 /usr/bin/cpanm
cat > /root/list << EOF
install DBD::mysql
install Config::Tiny
install Log::Dispatch
install Parallel::ForkManager
install Time::HiRes
install CPAN
install Digest::SHA
EOF
for package in `cat /root/list`
do
cpanm $package
done
3.安装MHA Node软件包,所有服务器都要安装
tar -xvf mha4mysql-node-0.54.tar.gz cd mha4mysql-node-0.54 perl Makefile.PL INSTALL_BASE=/usr/local/mha make && make install
4.安装MHA Manager软件包,只在Manager主机上安装
tar -xvf mha4mysql-manager-0.55.tar.gz cd mha4mysql-manager-0.55 perl Makefile.PL INSTALL_BASE=/usr/local/mha make && make install
cp samples/scripts/* /usr/local/mha/bin/
master_ip_failover:自动切换时vip管理的脚本
master_ip_online_change:手动切换使用的脚本
power_manager:故障发生后关闭主机的脚本
send_report:发送报警的脚本。
5.修改环境变量
将MHA Manager主机的/usr/local/mha/bin加入环境变量
6.添加软链接
为了不麻烦所有服务器都执行吧，其实最后两个mysql,mysqlbinlog的软链接只有Node服务器需要添加，其它的所有服务器都需要添加。
mkdir -p /usr/local/bin mkdir -p /usr/local/share/man/man1 mkdir -p /usr/local/share/perl5/MHA ln -s /usr/local/mha/bin/* /usr/local/bin; ln -s /usr/local/mha/man/man1/* /usr/local/share/man/man1; ln -s /usr/local/mha/lib/perl5/MHA /usr/local/share/perl5/MHA; ln -s /usr/local/mysql/bin/mysqlbinlog /usr/local/bin/mysqlbinlog; ln -s /usr/local/mysql/bin/mysql /usr/local/bin/mysql;
二、配置MHA
1.配置SSH无密码登入
（1）在manage配置到所有Node节点的无密码登入
ssh-keygen -t rsa 一直enter,会在/root/.ssh/下面生成id_rsa.pub ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]192.168.137.10 ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]192.168.137.20 ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]192.168.137.30
(2)在Node 10配置到Node 20,30的无密码登入
ssh-keygen -t rsa ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]192.168.137.20 ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]192.168.137.30
(3)在Node 20配置到Node 10,30的无密码登入
ssh-keygen -t rsa ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected] ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
(4)在Node 30配置到Node 10,20的无密码登入
ssh-keygen -t rsa ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected] ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]8.137.20
2. 搭建复制环境
复制环境之前已经搭建好，可以参考我前面写过的文章,复制用户和密码都是repl;每个Node上都必须创建这个repl账号，除非Node不作为故障专业的master
1.在所有Node上创建Manage监控用户
grant all privileges on *.* to ‘root‘@‘192.168.137.%‘ identified by ‘root‘;
三、配置Manage
1.配置启动文件
vim /usr/local/mha/ha1/ha1.cnf
[server default] manager_workdir=/usr/local/mha/ha1/workdir ##项目的主目录 manager_log=/usr/local/mha/ha1/workdir/manager.log ###mha记录日志 master_binlog_dir=/mysql/log ####node服务器的binlog存放路径，如果每个node的binlog路径不一致的话就在下面的每个server下面单独配置 master_ip_failover_script=/usr/local/mha/ha1/fail_script/master_ip_failover ####mha在线自动failover时处理VIP的配置文件 master_ip_online_change_script=/usr/local/mha/ha1/fail_script/master_ip_online_change ####在线手动执行master切换时VIP的处理文件 secondary_check_script=/usr/local/mha/bin/masterha_secondary_check -s backup -s master --user=root --master_host=master --master_ip=192.168.137.10 --master_port=3306 ##一旦MHA到master之间的网络出现问题，manager会尝试从backup登入到masger #report_script=/usr/local/mha/ha1/fail_script/send_report ###发生切换后执行的报警脚本 shutdown_script="" ####故障后关闭master主机的脚本（主要是使用keepalive做VIP时会出现脑裂导致VIP频繁切换所以会将故障的master关闭） ping_interval=1 ###监控mater，ping的频率 remote_workdir=/tmp ###node服务器在发生master切换时，binlog保持的路径，每个node都会在该目录下保存一份差异的binlog，除非没有差异。 repl_password=repl ##复制使用的用户名，每个node服务器都需要存在 repl_user=repl ##复制使用的密码 user=root ##mnager监控用的mysql root用户 password=root ##root用户密码 ssh_user=root ##ssh登入用户名 [server1] hostname=192.168.137.10 port=3306 candidate_master=1 check_repl_delay=0 [server2] hostname=192.168.137.20 port=3306 #master_binlog_dir=/mysql/log candidate_master=1 ##设置为候选master，如果设置该参数以后，发生主从切换以后将会将此从库提升为主库，即使这个主库不是集群中事件最新的slave check_repl_delay=0 ##默认情况下如果一个slave落后master 100M的relay logs的话，MHA将不会选择该slave作为一个新的master，因为对于这个slave的恢复需要花费很长时间，通过设置check_repl_delay=0,MHA触发切换在选择一个新master的时候将会忽略复制延时，这个参数对于设置了candidate_master=1的主机非常有用，因为这个候选主在切换的过程中一定是新的master [server3] hostname=192.168.137.30 port=3306 ignore_fail=1 ####如果不加上该参数，当该slave主机故障了，mha将无法启动，加上该参数会忽略该主机是否正常，在mha启动的时候加上参数--ignore_fail_on_start no_master=1 ###不将该主机转换为master
注意：对于上面的配置一定要确保server1和server2之间是最新的binlog,一般会配置二者为双主的半同步复制，这样就保证了它们之间的binlog是最新的，否则应用差异的binlog将花费非常长的时间（如果它们和master延时非常大的情况下）
2.master_ip_failover
VIP的配置可以使用keepalived也可以写脚本，keepalived对网络的要求很高否则容易脑裂，在我前面搭建双主环境讲过keepalived的搭建方法，我这里使用脚本的方式。
#!/usr/bin/env perl
use strict;
use warnings FATAL => ‘all‘;
use Getopt::Long;
my (
$command, $ssh_user, $orig_master_host, $orig_master_ip,
$orig_master_port, $new_master_host, $new_master_ip, $new_master_port, $new_master_user, $new_master_password
);
my $vip = ‘192.168.137.50/24‘; ###VIP
my $key = ‘1‘; ###用于区别本身的eth0
my $ssh_start_vip = "/sbin/ifconfig eth0:$key $vip";
my $ssh_stop_vip = "/sbin/ifconfig eth0:$key down";
GetOptions(
‘command=s‘ => \$command,
‘ssh_user=s‘ => \$ssh_user,
‘orig_master_host=s‘ => \$orig_master_host,
‘orig_master_ip=s‘ => \$orig_master_ip,
‘orig_master_port=i‘ => \$orig_master_port,
‘new_master_host=s‘ => \$new_master_host,
‘new_master_ip=s‘ => \$new_master_ip,
‘new_master_port=i‘ => \$new_master_port,
‘new_master_user=s‘ => \$new_master_user,
‘new_master_password=s‘ => \$new_master_password,
);
exit &main();
sub main {
print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";
if ( $command eq "stop" || $command eq "stopssh" ) {
my $exit_code = 1;
eval {
print "Disabling the VIP on old master: $orig_master_host \n";
&stop_vip();
$exit_code = 0;
};
if ([email protected]) {
warn "Got Error: [email protected]\n";
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "start" ) {
my $exit_code = 10;
eval {
print "Enabling the VIP - $vip on the new master - $new_master_host \n";
&start_vip();
$exit_code = 0;
};
if ([email protected]) {
warn [email protected];
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. OK \n";
exit 0;
}
else {
&usage();
exit 1;
}
}
sub start_vip() {
`ssh $ssh_user\@$new_master_host \" $ssh_start_vip \"`;
}
sub stop_vip() {
return 0 unless ($ssh_user);
`ssh $ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}
sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}
注意：需要手动先在master服务器上面添加VIP
/sbin/ifconfig eth0:1 192.168.137.50/24
3.master_ip_online_change
perl脚本
#!/usr/bin/env perl
use strict;
use warnings FATAL =>‘all‘;
use Getopt::Long;
my $vip = ‘192.168.137.50/24‘; # Virtual IP
my $key = "1";
my $ssh_start_vip = "/sbin/ifconfig eth0:$key $vip";
my $ssh_stop_vip = "/sbin/ifconfig eth0:$key down";
my $exit_code = 0;
my (
$command, $orig_master_is_new_slave, $orig_master_host,
$orig_master_ip, $orig_master_port, $orig_master_user,
$orig_master_password, $new_master_host,
$new_master_ip, $new_master_port, $new_master_user,
$new_master_password,
);
GetOptions(
‘command=s‘ => \$command,
‘orig_master_is_new_slave‘ => \$orig_master_is_new_slave,
‘orig_master_host=s‘ => \$orig_master_host,
‘orig_master_ip=s‘ => \$orig_master_ip,
‘orig_master_port=i‘ => \$orig_master_port,
‘orig_master_user=s‘ => \$orig_master_user,
‘orig_master_password=s‘ => \$orig_master_password,
‘new_master_host=s‘ => \$new_master_host,
‘new_master_ip=s‘ => \$new_master_ip,
‘new_master_port=i‘ => \$new_master_port,
‘new_master_user=s‘ => \$new_master_user,
‘new_master_password=s‘ => \$new_master_password,
);
exit &main();
sub main {
#print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";
if ( $command eq "stop" || $command eq "stopssh" ) {
# $orig_master_host, $orig_master_ip, $orig_master_port are passed.
# If you manage master ip address at global catalog database,
# invalidate orig_master_ip here.
my $exit_code = 1;
eval {
print "\n\n\n***************************************************************\n";
print "Disabling the VIP - $vip on old master: $orig_master_host\n";
print "***************************************************************\n\n\n\n";
&stop_vip();
$exit_code = 0;
};
if ([email protected]) {
warn "Got Error: [email protected]\n";
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "start" ) {
# all arguments are passed.
# If you manage master ip address at global catalog database,
# activate new_master_ip here.
# You can also grant write access (create user, set read_only=0, etc) here.
my $exit_code = 10;
eval {
print "\n\n\n***************************************************************\n";
print "Enabling the VIP - $vip on new master: $new_master_host \n";
print "***************************************************************\n\n\n\n";
&start_vip();
$exit_code = 0;
};
if ([email protected]) {
warn [email protected];
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. OK \n";
`ssh $orig_master_user\@$orig_master_host \" $ssh_start_vip \"`;
exit 0;
}
else {
&usage();
exit 1;
}
}
# A simple system call that enable the VIP on the new master
sub start_vip() {
`ssh $new_master_user\@$new_master_host \" $ssh_start_vip \"`;
}
# A simple system call that disable the VIP on the old_master
sub stop_vip() {
`ssh $orig_master_user\@$orig_master_host \" $ssh_stop_vip \"`;
}
sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}
shell脚本
#/bin/bash
#source /root/.bash_profile
vip=`echo ‘192.168.137.50/24‘` # Virtual IP
key=`echo ‘1‘`
command=`echo "$1" | awk -F = ‘{print $2}‘`
orig_master_host=`echo "$2" | awk -F = ‘{print $2}‘`
new_master_host=`echo "$7" | awk -F = ‘{print $2}‘`
stop_vip=`echo "ssh [email protected]$orig_master_host /sbin/ifconfig eth0:$key down"`
start_vip=`echo "ssh [email protected]$new_master_host /sbin/ifconfig eth0:$key $vip"`
if [ $command = ‘stop‘ ]
then
echo -e "\n\n\n***************************************************************\n"
echo -e "Disabling the VIP - $vip on old master: $orig_master_host\n"
$stop_vip
if [ $? -eq 0 ]
then
echo "Disabled the VIP successfully"
else
echo "Disabled the VIP failed"
fi
echo -e "***************************************************************\n\n\n\n"
fi
if [ $command = ‘start‘ -o $command = ‘status‘ ]
then
echo -e "\n\n\n***************************************************************\n"
echo -e "Enabling the VIP - $vip on new master: $new_master_host \n"
$start_vip
if [ $? -eq 0 ]
then
echo "Enabled the VIP successfully"
else
echo "Enabled the VIP failed"
fi
echo -e "***************************************************************\n\n\n\n"
fi
4.send_report
#!/usr/bin/perl
# Copyright (C) 2011 DeNA Co.,Ltd.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
## Note: This is a sample script and is not complete. Modify the script based on your environment.
use strict;
use warnings FATAL => ‘all‘;
use Mail::Sender;
use Getopt::Long;
#new_master_host and new_slave_hosts are set only when recovering master succeeded
my ( $dead_master_host, $new_master_host, $new_slave_hosts, $subject, $body );
my $smtp=‘smtp.163.com‘;
my $mail_from=‘xxxx‘;
my $mail_user=‘xxxxx‘;
my $mail_pass=‘xxxxx‘;
my $mail_to=[‘xxxx‘,‘xxxx‘];
GetOptions(
‘orig_master_host=s‘ => \$dead_master_host,
‘new_master_host=s‘ => \$new_master_host,
‘new_slave_hosts=s‘ => \$new_slave_hosts,
‘subject=s‘ => \$subject,
‘body=s‘ => \$body,
);
mailToContacts($smtp,$mail_from,$mail_user,$mail_pass,$mail_to,$subject,$body);
sub mailToContacts {
my ( $smtp, $mail_from, $user, $passwd, $mail_to, $subject, $msg ) = @_;
open my $DEBUG, "> /tmp/monitormail.log"
or die "Can‘t open the debug file:$!\n";
my $sender = new Mail::Sender {
ctype => ‘text/plain; charset=utf-8‘,
encoding => ‘utf-8‘,
smtp => $smtp,
from => $mail_from,
auth => ‘LOGIN‘,
TLS_allowed => ‘0‘,
authid => $user,
authpwd => $passwd,
to => $mail_to,
subject => $subject,
debug => $DEBUG
};
$sender->MailMsg(
{ msg => $msg,
debug => $DEBUG
}
) or print $Mail::Sender::Error;
return 1;
}
# Do whatever you want here
exit 0;
这里得先安装mutt,安装方法这里不做介绍
四、配置relay_log的清除方式（在每个Node上）
(1)所有Node的cnf配置文件加上
relay_log_purge=0
MHA在发生切换的过程中，从库的恢复过程中依赖于relay log的相关信息，所以这里要将relay log的自动清除设置为OFF，采用手动清除relay log的方式。
在默认情况下，从服务器上的中继日志会在SQL线程执行完毕后被自动删除。但是在MHA环境中，这些中继日志在恢复其他从服务器时可能会被用到，因此需要禁用中继日志的自动删除功能。定期清除中继日志需要考虑到复制延时的问题。在ext3的文件系统下，删除大的文件需要一定的时间，会导致严重的复制延时。为了避免复制延时，需要暂时为中继日志创建硬链接，因为在linux系统中通过硬链接删除大文件速度会很快。
提示：在mysql数据库中，删除大表时，通常也采用建立硬链接的方式
MHA节点中包含了pure_relay_logs命令工具，它可以为中继日志创建硬链接，执行SET GLOBAL relay_log_purge=1,等待几秒钟以便SQL线程切换到新的中继日志，再执行SET GLOBAL relay_log_purge=0。
pure_relay_logs脚本参数如下所示：
--user mysql 用户名 --password mysql 密码 --port 端口号 --workdir 指定创建relay log的硬链接的位置，默认是/var/tmp，由于系统不同分区创建硬链接文件会失败，故需要执行硬链接具体位置，成功执行脚本后，硬链接的中继日志文件被删除 --disable_relay_log_purge 默认情况下，如果relay_log_purge=1，脚本会什么都不清理，自动退出，通过设定这个参数，当relay_log_purge=1的情况下会将relay_log_purge设置为0。清理relay log之后，最后将参数设置为OFF。
(2)在每台slave Node上创建
vim /usr/local/mha/purge_relay_log.sh
#!/bin/bash user=root passwd=root ####确保用户和密码能通过127.0.0.1登入 host=‘127.0.0.1‘ port=3306 work_dir=‘/mysql/data‘ purge=‘/usr/local/mha/bin/purge_relay_logs‘ $purge --user=$user --password=$passwd --host=$host --disable_relay_log_purge --port=$port --workdir=$work_dir >> /usr/local/mha/purge_relay_logs.log 2>&1
chmod u+x /usr/local/mha/purge_relay_log.sh
将脚本加入到os定时任务中
五、检测启动MHA
1.检查ssh配置
masterha_check_ssh --conf=/usr/local/mha/ha1/ha1.cnf
[root@monitor ha1]# masterha_check_ssh --conf=/usr/local/mha/ha1/ha1.cnf Thu Aug 25 14:53:30 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Thu Aug 25 14:53:30 2016 - [info] Reading application default configurations from /usr/local/mha/ha1/ha1.cnf.. Thu Aug 25 14:53:30 2016 - [info] Reading server configurations from /usr/local/mha/ha1/ha1.cnf.. Thu Aug 25 14:53:30 2016 - [info] Starting SSH connection tests.. Thu Aug 25 14:53:35 2016 - [debug] Thu Aug 25 14:53:31 2016 - [debug] Connecting via SSH from [email protected]192.168.137.20(192.168.137.20:22) to [email protected]192.168.137.10(192.168.137.10:22).. Thu Aug 25 14:53:33 2016 - [debug] ok. Thu Aug 25 14:53:33 2016 - [debug] Connecting via SSH from [email protected]192.168.137.20(192.168.137.20:22) to [email protected]192.168.137.30(192.168.137.30:22).. Thu Aug 25 14:53:34 2016 - [debug] ok. Thu Aug 25 14:53:35 2016 - [debug] Thu Aug 25 14:53:31 2016 - [debug] Connecting via SSH from [email protected]192.168.137.30(192.168.137.30:22) to [email protected]192.168.137.10(192.168.137.10:22).. Thu Aug 25 14:53:33 2016 - [debug] ok. Thu Aug 25 14:53:33 2016 - [debug] Connecting via SSH from [email protected]192.168.137.30(192.168.137.30:22) to [email protected]192.168.137.20(192.168.137.20:22).. Thu Aug 25 14:53:34 2016 - [debug] ok. Thu Aug 25 14:53:36 2016 - [debug] Thu Aug 25 14:53:30 2016 - [debug] Connecting via SSH from [email protected]192.168.137.10(192.168.137.10:22) to [email protected]192.168.137.20(192.168.137.20:22).. Thu Aug 25 14:53:34 2016 - [debug] ok. Thu Aug 25 14:53:34 2016 - [debug] Connecting via SSH from [email protected]192.168.137.10(192.168.137.10:22) to [email protected]192.168.137.30(192.168.137.30:22).. Thu Aug 25 14:53:35 2016 - [debug] ok. Thu Aug 25 14:53:36 2016 - [info] All SSH connection tests passed successfully.
可以看到每个Node到其它的Node都是相通的。
2.检查整个复制环境
masterha_check_repl --conf=/usr/local/mha/ha1/ha1.cnf
[root@monitor ha1]# masterha_check_repl --conf=/usr/local/mha/ha1/ha1.cnf
Thu Aug 25 16:09:19 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Thu Aug 25 16:09:19 2016 - [info] Reading application default configurations from /usr/local/mha/ha1/ha1.cnf..
Thu Aug 25 16:09:19 2016 - [info] Reading server configurations from /usr/local/mha/ha1/ha1.cnf..
Thu Aug 25 16:09:19 2016 - [info] MHA::MasterMonitor version 0.55.
Thu Aug 25 16:09:20 2016 - [info] Dead Servers:
Thu Aug 25 16:09:20 2016 - [info] Alive Servers:
Thu Aug 25 16:09:20 2016 - [info] 192.168.137.10(192.168.137.10:3306)
Thu Aug 25 16:09:20 2016 - [info] 192.168.137.20(192.168.137.20:3306)
Thu Aug 25 16:09:20 2016 - [info] 192.168.137.30(192.168.137.30:3306)
Thu Aug 25 16:09:20 2016 - [info] Alive Slaves:
Thu Aug 25 16:09:20 2016 - [info] 192.168.137.20(192.168.137.20:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Thu Aug 25 16:09:20 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306)
Thu Aug 25 16:09:20 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Thu Aug 25 16:09:20 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Thu Aug 25 16:09:20 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306)
Thu Aug 25 16:09:20 2016 - [info] Not candidate for the new Master (no_master is set)
Thu Aug 25 16:09:20 2016 - [info] Current Alive Master: 192.168.137.10(192.168.137.10:3306)
Thu Aug 25 16:09:20 2016 - [info] Checking slave configurations..
Thu Aug 25 16:09:20 2016 - [info] read_only=1 is not set on slave 192.168.137.20(192.168.137.20:3306).
Thu Aug 25 16:09:20 2016 - [info] Checking replication filtering settings..
Thu Aug 25 16:09:20 2016 - [info] binlog_do_db= , binlog_ignore_db=
Thu Aug 25 16:09:20 2016 - [info] Replication filtering check ok.
Thu Aug 25 16:09:20 2016 - [info] Starting SSH connection tests..
Thu Aug 25 16:09:25 2016 - [info] All SSH connection tests passed successfully.
Thu Aug 25 16:09:25 2016 - [info] Checking MHA Node version..
Thu Aug 25 16:09:26 2016 - [info] Version check ok.
Thu Aug 25 16:09:26 2016 - [info] Checking SSH publickey authentication settings on the current master..
Thu Aug 25 16:09:27 2016 - [info] HealthCheck: SSH to 192.168.137.10 is reachable.
Thu Aug 25 16:09:29 2016 - [info] Master MHA Node version is 0.54.
Thu Aug 25 16:09:29 2016 - [info] Checking recovery script configurations on the current master..
Thu Aug 25 16:09:29 2016 - [info] Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/mysql/log --output_file=/tmp/save_binary_logs_test --manager_version=0.55 --start_file=mysql-bin.000138
Thu Aug 25 16:09:29 2016 - [info] Connecting to [email protected]192.168.137.10(192.168.137.10)..
Creating /tmp if not exists.. ok.
Checking output directory is accessible or not..
ok.
Binlog found at /mysql/log, up to mysql-bin.000138
Thu Aug 25 16:09:30 2016 - [info] Master setting check done.
Thu Aug 25 16:09:30 2016 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Thu Aug 25 16:09:30 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user=‘root‘ --slave_host=192.168.137.20 --slave_ip=192.168.137.20 --slave_port=3306 --workdir=/tmp --target_version=5.6.15-log --manager_version=0.55 --relay_log_info=/mysql/data/relay-log.info --relay_dir=/mysql/data/ --slave_pass=xxx
Thu Aug 25 16:09:30 2016 - [info] Connecting to [email protected]192.168.137.20(192.168.137.20:22)..
Checking slave recovery environment settings..
Opening /mysql/data/relay-log.info ... ok.
Relay log found at /mysql/data, up to mysql-relay-bin.000006
Temporary relay log file is /mysql/data/mysql-relay-bin.000006
Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Thu Aug 25 16:09:31 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user=‘root‘ --slave_host=192.168.137.30 --slave_ip=192.168.137.30 --slave_port=3306 --workdir=/tmp --target_version=5.6.15-log --manager_version=0.55 --relay_log_info=/mysql/data/relay-log.info --relay_dir=/mysql/data/ --slave_pass=xxx
Thu Aug 25 16:09:31 2016 - [info] Connecting to [email protected]192.168.137.30(192.168.137.30:22)..
Checking slave recovery environment settings..
Opening /mysql/data/relay-log.info ... ok.
Relay log found at /mysql/data, up to mysql-relay-bin.000002
Temporary relay log file is /mysql/data/mysql-relay-bin.000002
Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Thu Aug 25 16:09:32 2016 - [info] Slaves settings check done.
Thu Aug 25 16:09:32 2016 - [info]
192.168.137.10 (current master)
+--192.168.137.20
+--192.168.137.30
Thu Aug 25 16:09:32 2016 - [info] Checking replication health on 192.168.137.20..
Thu Aug 25 16:09:32 2016 - [info] ok.
Thu Aug 25 16:09:32 2016 - [info] Checking replication health on 192.168.137.30..
Thu Aug 25 16:09:32 2016 - [info] ok.
Thu Aug 25 16:09:32 2016 - [info] Checking master_ip_failover_script status:
Thu Aug 25 16:09:32 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.137.10 --orig_master_ip=192.168.137.10 --orig_master_port=3306
IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 192.168.137.50/24===
Checking the Status of the script.. OK
Thu Aug 25 16:09:32 2016 - [info] OK.
Thu Aug 25 16:09:32 2016 - [warning] shutdown_script is not defined.
Thu Aug 25 16:09:32 2016 - [info] Got exit code 0 (Not master dead).
MySQL Replication Health is OK.
--ignore_fail_on_start： 当有slave 节点宕掉时，默认是启动不了的，加上 --ignore_fail_on_start 即使有节点宕掉也能启动MHA，加上该参数会忽略启动文件中配置ignore_fail=1的server
3.检查MHA Manager状态
masterha_check_status --conf=/usr/local/mha/ha1/ha1.cnf
由于mha还没有启动，所以这里检测是stopped
4.启动MHA
nohup masterha_manager --conf=/usr/local/mha/ha1/ha1.cnf --ignore_fail_on_start --ignore_last_failover < /dev/null > /usr/local/mha/ha1/start.log 2>&1 &
--remove_dead_master_conf：该参数代表当发生主从切换后，老的主库的ip将会从配置文件中移除。这里暂时不使用该参数，因为发生使用该参数会将ha1.cnf配置文件搞乱。
--start_log:日志。
--ignore_last_failover：发生主从切换后，MHAmanager服务会自动停掉，且在manager_workdir目录下面生成文件app1.failover.complete，若要启动MHA，必须先删除该文件，该参数代表忽略上次MHA触发切换产生的文件，这里设置为-ignore_last_failover。 在缺省情况下，如果MHA检测到连续发生宕机，且两次宕机间隔不足8小时的话，则不会进行Failover，之所以这样限制是为了避免ping-pong效应。
--ignore_fail_on_start： 当有slave 节点宕掉时，默认是启动不了的，加上 --ignore_fail_on_start 即使有节点宕掉也能启动MHA，加上该参数会忽略启动文件中配置ignore_fail=1的server。
(1)再次查看MHA状态是否正常：
[root@monitor ha1]# masterha_check_status --conf=/usr/local/mha/ha1/ha1.cnf ha1 (pid:6371) is running(0:PING_OK), master:192.168.137.10 [root@monitor ha1]#
(2)查看启动日志
cat manager.log
Thu Aug 25 17:11:50 2016 - [info] 192.168.137.10 (current master) +--192.168.137.20 +--192.168.137.30 Thu Aug 25 17:11:50 2016 - [info] Checking master_ip_failover_script status: Thu Aug 25 17:11:50 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.137.10 --orig_master_ip=192.168.137.10 --orig_master_port=3306 IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 192.168.137.50/24=== Checking the Status of the script.. OK Thu Aug 25 17:11:50 2016 - [info] OK. Thu Aug 25 17:11:50 2016 - [warning] shutdown_script is not defined. Thu Aug 25 17:11:50 2016 - [info] Set master ping interval 1 seconds. Thu Aug 25 17:11:50 2016 - [info] Set secondary check script: /usr/local/mha/bin/masterha_secondary_check -s backup -s master --user=root --master_host=master --master_ip=192.168.137.10 --master_port=3306 Thu Aug 25 17:11:50 2016 - [info] Starting ping health check on 192.168.137.10(192.168.137.10:3306).. Thu Aug 25 17:11:50 2016 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn‘t respond.. [[email protected] ha1]#
(3)产生的文件
ha1.master_status.health：mha正常启动会产生该文件
manager.log：mha监控日志
start.log:mha启动时生成的日志
5.关闭MHA
masterha_stop --conf=/usr/local/mha/ha1/ha1.cnf
六、故障处理步骤
发生主从切换后，MHA服务会自动停掉
1.检查日志
检查故障处理的日志，确保故障正常转移。
cat /usr/local/mha/ha1/manager.log
2.处理故障master
处理故障的master，将其配置为从库chang到新的master，可以从manager.log找到change语句。
grep "CHANGE MASTER TO MASTER" /usr/local/mha/ha1/manager.log | tail -1
Fri Aug 26 12:04:22 2016 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.137.10‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000143‘, MASTER_LOG_POS=22123166, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘;
注意：这里要确保slave的SQL_THREAD和IO_TRREAD正常，如果是配置半同步复制要确保半同步复制启动正常，可以执行"show status like ‘%rpl_%‘;",具体参考前面半同步复制的搭建。
3.修改ha1.cnf配置文件
需要修改"secondary_check_script"选项中的master_host、master_ip、master_port为新的master;如果两台电脑的配置都相同的话其它地方不用修改。
4.删除fail文件（非必需）
由于启动mha的时候加上了--ignore_last_failover参数，所以不删除failower生成的文件也能启动，否则需要删除failower生成的文件“ha1.failover.complete”。
rm -f /usr/local/mha/ha1/ha1.failover.complete
5.check检查
检查SSH配置 masterha_check_ssh --conf=/usr/local/mha/ha1/ha1.cnf 检查复制 masterha_check_repl --conf=/usr/local/mha/ha1/ha1.cnf 检查状态 masterha_check_status --conf=/usr/local/mha/ha1/ha1.cnf
必需保证所有的检查都通过
6.启动MHA
nohup masterha_manager --conf=/usr/local/mha/ha1/ha1.cnf --ignore_fail_on_start --ignore_last_failover < /dev/null > /usr/local/mha/ha1/start.log 2>&1 &
七、模拟Failover
1.自动failover
我这里是异步复制，137.20是当前的master，然后在137.20上执行并发插入，同时关闭137.10和137.30的IO线程，在137.20上压测一段时间，然后先开启137.30的IO线程，过几秒钟再开启137.10的IO线程；保证137.30的binlog比候选的137.10的binlog更新。
master 137.20（22497564）
candidate slave:137.10(pos=9857376)
new replay slave:137.30(pos=22461852)
Fri Aug 26 11:57:36 2016 - [warning] Got error on MySQL select ping: 2013 (Lost connection to MySQL server during query)
Fri Aug 26 11:57:36 2016 - [info] Executing SSH check script: save_binary_logs --command=test --start_pos=4 --binlog_dir=/mysql/log --output_file=/tmp/save_binary_logs_test --manager_version=0.55 --binlog_prefix=mysql-bin
Fri Aug 26 11:57:36 2016 - [info] Executing seconary network check script: /usr/local/mha/bin/masterha_secondary_check -s backup -s master --user=root --master_host=master --master_ip=192.168.137.10 --master_port=3306 --user=root --master_host=192.168.137.20 --master_ip=192.168.137.20 --master_port=3306
Fri Aug 26 11:57:37 2016 - [warning] Got error on MySQL connect: 2003 (Can‘t connect to MySQL server on ‘192.168.137.20‘ (111))
Fri Aug 26 11:57:37 2016 - [warning] Connection failed 1 time(s)..
Fri Aug 26 11:57:38 2016 - [warning] Got error on MySQL connect: 2003 (Can‘t connect to MySQL server on ‘192.168.137.20‘ (111))
Fri Aug 26 11:57:38 2016 - [warning] Connection failed 2 time(s)..
Fri Aug 26 11:57:38 2016 - [info] HealthCheck: SSH to 192.168.137.20 is reachable.
Monitoring server backup is reachable, Master is not reachable from backup. OK.
Fri Aug 26 11:57:39 2016 - [warning] Got error on MySQL connect: 2003 (Can‘t connect to MySQL server on ‘192.168.137.20‘ (111))
Fri Aug 26 11:57:39 2016 - [warning] Connection failed 3 time(s)..
Monitoring server master is reachable, Master is not reachable from master. OK.
Fri Aug 26 11:57:41 2016 - [info] Master is not reachable from all other monitoring servers. Failover should start.
Fri Aug 26 11:57:41 2016 - [warning] Master is not reachable from health checker!
Fri Aug 26 11:57:41 2016 - [warning] Master 192.168.137.20(192.168.137.20:3306) is not reachable!
Fri Aug 26 11:57:41 2016 - [warning] SSH is reachable.
Fri Aug 26 11:57:41 2016 - [info] Connecting to a master server failed. Reading configuration file /etc/masterha_default.cnf and /usr/local/mha/ha1/ha1.cnf again, and trying to connect to all servers to check server status..
Fri Aug 26 11:57:41 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Fri Aug 26 11:57:41 2016 - [info] Reading application default configurations from /usr/local/mha/ha1/ha1.cnf..
Fri Aug 26 11:57:41 2016 - [info] Reading server configurations from /usr/local/mha/ha1/ha1.cnf..
Fri Aug 26 11:57:42 2016 - [info] Dead Servers:
Fri Aug 26 11:57:42 2016 - [info] 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:42 2016 - [info] Alive Servers:
Fri Aug 26 11:57:42 2016 - [info] 192.168.137.10(192.168.137.10:3306)
Fri Aug 26 11:57:42 2016 - [info] 192.168.137.30(192.168.137.30:3306)
Fri Aug 26 11:57:42 2016 - [info] Alive Slaves:
Fri Aug 26 11:57:42 2016 - [info] 192.168.137.10(192.168.137.10:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:42 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:42 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Fri Aug 26 11:57:42 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:42 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:42 2016 - [info] Not candidate for the new Master (no_master is set)
Fri Aug 26 11:57:42 2016 - [info] Checking slave configurations..
Fri Aug 26 11:57:42 2016 - [info] read_only=1 is not set on slave 192.168.137.10(192.168.137.10:3306).
Fri Aug 26 11:57:42 2016 - [info] Checking replication filtering settings..
Fri Aug 26 11:57:42 2016 - [info] Replication filtering check ok.
Fri Aug 26 11:57:42 2016 - [info] Master is down!
Fri Aug 26 11:57:42 2016 - [info] Terminating monitoring script.
Fri Aug 26 11:57:42 2016 - [info] Got exit code 20 (Master dead).
Fri Aug 26 11:57:42 2016 - [info] MHA::MasterFailover version 0.55.
Fri Aug 26 11:57:42 2016 - [info] Starting master failover.
Fri Aug 26 11:57:42 2016 - [info]
Fri Aug 26 11:57:42 2016 - [info] * Phase 1: Configuration Check Phase..
Fri Aug 26 11:57:42 2016 - [info]
Fri Aug 26 11:57:44 2016 - [info] Dead Servers:
Fri Aug 26 11:57:44 2016 - [info] 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:44 2016 - [info] Checking master reachability via mysql(double check)..
Fri Aug 26 11:57:44 2016 - [info] ok.
Fri Aug 26 11:57:44 2016 - [info] Alive Servers:
Fri Aug 26 11:57:44 2016 - [info] 192.168.137.10(192.168.137.10:3306)
Fri Aug 26 11:57:44 2016 - [info] 192.168.137.30(192.168.137.30:3306)
Fri Aug 26 11:57:44 2016 - [info] Alive Slaves:
Fri Aug 26 11:57:44 2016 - [info] 192.168.137.10(192.168.137.10:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:44 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:44 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Fri Aug 26 11:57:44 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:44 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:44 2016 - [info] Not candidate for the new Master (no_master is set)
Fri Aug 26 11:57:44 2016 - [info] ** Phase 1: Configuration Check Phase completed.
Fri Aug 26 11:57:44 2016 - [info]
Fri Aug 26 11:57:44 2016 - [info] * Phase 2: Dead Master Shutdown Phase..
Fri Aug 26 11:57:44 2016 - [info]
Fri Aug 26 11:57:44 2016 - [info] Forcing shutdown so that applications never connect to the current master..
Fri Aug 26 11:57:44 2016 - [info] Executing master IP deactivatation script:
Fri Aug 26 11:57:44 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_failover --orig_master_host=192.168.137.20 --orig_master_ip=192.168.137.20 --orig_master_port=3306 --command=stopssh --ssh_user=root
IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 192.168.137.50/24===
Disabling the VIP on old master: 192.168.137.20
Fri Aug 26 11:57:45 2016 - [info] done.
Fri Aug 26 11:57:45 2016 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.
Fri Aug 26 11:57:45 2016 - [info] * Phase 2: Dead Master Shutdown Phase completed.
Fri Aug 26 11:57:45 2016 - [info]
Fri Aug 26 11:57:45 2016 - [info] * Phase 3: Master Recovery Phase..
Fri Aug 26 11:57:45 2016 - [info]
Fri Aug 26 11:57:45 2016 - [info] * Phase 3.1: Getting Latest Slaves Phase..
Fri Aug 26 11:57:45 2016 - [info]
Fri Aug 26 11:57:45 2016 - [info] The latest binary log file/position on all slaves is mysql-bin.000074:22461852
Fri Aug 26 11:57:45 2016 - [info] Latest slaves (Slaves that received relay log files to the latest):
Fri Aug 26 11:57:45 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:45 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:45 2016 - [info] Not candidate for the new Master (no_master is set)
Fri Aug 26 11:57:45 2016 - [info] The oldest binary log file/position on all slaves is mysql-bin.000074:9857376
Fri Aug 26 11:57:45 2016 - [info] Oldest slaves:
Fri Aug 26 11:57:45 2016 - [info] 192.168.137.10(192.168.137.10:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:45 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:45 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Fri Aug 26 11:57:45 2016 - [info]
Fri Aug 26 11:57:45 2016 - [info] * Phase 3.2: Saving Dead Master‘s Binlog Phase..
Fri Aug 26 11:57:45 2016 - [info]
Fri Aug 26 11:57:46 2016 - [info] Fetching dead master‘s binary logs..
Fri Aug 26 11:57:46 2016 - [info] Executing command on the dead master 192.168.137.20(192.168.137.20:3306): save_binary_logs --command=save --start_file=mysql-bin.000074 --start_pos=22461852 --binlog_dir=/mysql/log --output_file=/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55
Creating /tmp if not exists.. ok.
Concat binary/relay logs from mysql-bin.000074 pos 22461852 to mysql-bin.000074 EOF into /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog ..
Dumping binlog format description event, from position 0 to 120.. ok.
Dumping effective binlog data from /mysql/log/mysql-bin.000074 position 22461852 to tail(22497564).. ok.
Concat succeeded.
Fri Aug 26 11:57:49 2016 - [info] scp from [email protected]:/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog to local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog succeeded.
Fri Aug 26 11:57:52 2016 - [info] HealthCheck: SSH to 192.168.137.10 is reachable.
Fri Aug 26 11:57:55 2016 - [info] HealthCheck: SSH to 192.168.137.30 is reachable.
Fri Aug 26 11:57:55 2016 - [info]
Fri Aug 26 11:57:55 2016 - [info] * Phase 3.3: Determining New Master Phase..
Fri Aug 26 11:57:55 2016 - [info]
Fri Aug 26 11:57:55 2016 - [info] Finding the latest slave that has all relay logs for recovering other slaves..
Fri Aug 26 11:57:55 2016 - [info] Checking whether 192.168.137.30 has relay logs from the oldest position..
Fri Aug 26 11:57:55 2016 - [info] Executing command: apply_diff_relay_logs --command=find --latest_mlf=mysql-bin.000074 --latest_rmlp=22461852 --target_mlf=mysql-bin.000074 --target_rmlp=9857376 --server_id=30 --workdir=/tmp --timestamp=20160826115742 --manager_version=0.55 --relay_log_info=/mysql/data/relay-log.info --relay_dir=/mysql/data/ :
Opening /mysql/data/relay-log.info ... ok.
Relay log found at /mysql/data, up to mysql-relay-bin.000003
Fast relay log position search succeeded.
Target relay log file/position found. start_file:mysql-relay-bin.000003, start_pos:9857539.
Target relay log FOUND!
Fri Aug 26 11:57:56 2016 - [info] OK. 192.168.137.30 has all relay logs.
Fri Aug 26 11:57:56 2016 - [info] Searching new master from slaves..
Fri Aug 26 11:57:56 2016 - [info] Candidate masters from the configuration file:
Fri Aug 26 11:57:56 2016 - [info] 192.168.137.10(192.168.137.10:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:56 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:56 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Fri Aug 26 11:57:56 2016 - [info] Non-candidate masters:
Fri Aug 26 11:57:56 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled
Fri Aug 26 11:57:56 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306)
Fri Aug 26 11:57:56 2016 - [info] Not candidate for the new Master (no_master is set)
Fri Aug 26 11:57:56 2016 - [info] Searching from candidate_master slaves which have received the latest relay log events..
Fri Aug 26 11:57:56 2016 - [info] Not found.
Fri Aug 26 11:57:56 2016 - [info] Searching from all candidate_master slaves..
Fri Aug 26 11:57:56 2016 - [info] New master is 192.168.137.10(192.168.137.10:3306)
Fri Aug 26 11:57:56 2016 - [info] Starting master failover..
Fri Aug 26 11:57:56 2016 - [info]
From:
192.168.137.20 (current master)
+--192.168.137.10
+--192.168.137.30
To:
192.168.137.10 (new master)
+--192.168.137.30
Fri Aug 26 11:57:56 2016 - [info]
Fri Aug 26 11:57:56 2016 - [info] * Phase 3.3: New Master Diff Log Generation Phase..
Fri Aug 26 11:57:56 2016 - [info]
Fri Aug 26 11:57:56 2016 - [info] Server 192.168.137.10 received relay logs up to: mysql-bin.000074:9857376
Fri Aug 26 11:57:56 2016 - [info] Need to get diffs from the latest slave(192.168.137.30) up to: mysql-bin.000074:22461852 (using the latest slave‘s relay logs)
Fri Aug 26 11:57:56 2016 - [info] Connecting to the latest slave host 192.168.137.30, generating diff relay log files..
Fri Aug 26 11:57:56 2016 - [info] Executing command: apply_diff_relay_logs --command=generate_and_send --scp_user=root --scp_host=192.168.137.10 --latest_mlf=mysql-bin.000074 --latest_rmlp=22461852 --target_mlf=mysql-bin.000074 --target_rmlp=9857376 --server_id=30 --diff_file_readtolatest=/tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog --workdir=/tmp --timestamp=20160826115742 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --relay_log_info=/mysql/data/relay-log.info --relay_dir=/mysql/data/
Fri Aug 26 11:58:02 2016 - [info]
Opening /mysql/data/relay-log.info ... ok.
Relay log found at /mysql/data, up to mysql-relay-bin.000003
Fast relay log position search succeeded.
Target relay log file/position found. start_file:mysql-relay-bin.000003, start_pos:9857539.
Concat binary/relay logs from mysql-relay-bin.000003 pos 9857539 to mysql-relay-bin.000003 EOF into /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog ..
Dumping binlog format description event, from position 0 to 283.. ok.
Dumping effective binlog data from /mysql/data/mysql-relay-bin.000003 position 9857539 to tail(22462015).. ok.
Concat succeeded.
Generating diff relay log succeeded. Saved at /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog .
scp slave:/tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog to [email protected](22) succeeded.
Fri Aug 26 11:58:02 2016 - [info] Generating diff files succeeded.
Fri Aug 26 11:58:02 2016 - [info] Sending binlog..
Fri Aug 26 11:58:04 2016 - [info] scp from local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog to [email protected]:/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog succeeded.
Fri Aug 26 11:58:04 2016 - [info]
Fri Aug 26 11:58:04 2016 - [info] * Phase 3.4: Master Log Apply Phase..
Fri Aug 26 11:58:04 2016 - [info]
Fri Aug 26 11:58:04 2016 - [info] *NOTICE: If any error happens from this phase, manual recovery is needed.
Fri Aug 26 11:58:04 2016 - [info] Starting recovery on 192.168.137.10(192.168.137.10:3306)..
Fri Aug 26 11:58:04 2016 - [info] Generating diffs succeeded.
Fri Aug 26 11:58:04 2016 - [info] Waiting until all relay logs are applied.
Fri Aug 26 12:00:06 2016 - [info] done.
Fri Aug 26 12:00:06 2016 - [info] Getting slave status..
Fri Aug 26 12:00:06 2016 - [info] This slave(192.168.137.10)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000074:9857376). No need to recover from Exec_Master_Log_Pos.
Fri Aug 26 12:00:06 2016 - [info] Connecting to the target slave host 192.168.137.10, running recover script..
Fri Aug 26 12:00:06 2016 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘root‘ --slave_host=192.168.137.10 --slave_ip=192.168.137.10 --slave_port=3306 --apply_files=/tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog,/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog --workdir=/tmp --target_version=5.6.15-log --timestamp=20160826115742 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --slave_pass=xxx
Fri Aug 26 12:04:22 2016 - [info]
Concat all apply files to /tmp/total_binlog_for_192.168.137.10_3306.20160826115742.binlog ..
Copying the first binlog file /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog to /tmp/total_binlog_for_192.168.137.10_3306.20160826115742.binlog.. ok.
Dumping binlog head events (rotate events), skipping format description events from /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog.. dumped up to pos 120. ok.
/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog has effective binlog events from pos 120.
Dumping effective binlog data from /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog position 120 to tail(35832).. ok.
Concat succeeded.
All apply target binary logs are concatinated at /tmp/total_binlog_for_192.168.137.10_3306.20160826115742.binlog .
MySQL client version is 5.6.15. Using --binary-mode.
Applying differential binary/relay log files /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog,/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog on 192.168.137.10:3306. This may take long time...
Applying log files succeeded.
Fri Aug 26 12:04:22 2016 - [info] All relay logs were successfully applied.
Fri Aug 26 12:04:22 2016 - [info] Getting new master‘s binlog name and position..
Fri Aug 26 12:04:22 2016 - [info] mysql-bin.000143:22123166
Fri Aug 26 12:04:22 2016 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.137.10‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000143‘, MASTER_LOG_POS=22123166, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘;
Fri Aug 26 12:04:22 2016 - [info] Executing master IP activate script:
Fri Aug 26 12:04:22 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_failover --command=start --ssh_user=root --orig_master_host=192.168.137.20 --orig_master_ip=192.168.137.20 --orig_master_port=3306 --new_master_host=192.168.137.10 --new_master_ip=192.168.137.10 --new_master_port=3306 --new_master_user=‘root‘ --new_master_password=‘root‘
IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 192.168.137.50/24===
Enabling the VIP - 192.168.137.50/24 on the new master - 192.168.137.10
Fri Aug 26 12:04:25 2016 - [info] OK.
Fri Aug 26 12:04:25 2016 - [info] ** Finished master recovery successfully.
Fri Aug 26 12:04:25 2016 - [info] * Phase 3: Master Recovery Phase completed.
Fri Aug 26 12:04:25 2016 - [info]
Fri Aug 26 12:04:25 2016 - [info] * Phase 4: Slaves Recovery Phase..
Fri Aug 26 12:04:25 2016 - [info]
Fri Aug 26 12:04:25 2016 - [info] * Phase 4.1: Starting Parallel Slave Diff Log Generation Phase..
Fri Aug 26 12:04:25 2016 - [info]
Fri Aug 26 12:04:25 2016 - [info] -- Slave diff file generation on host 192.168.137.30(192.168.137.30:3306) started, pid: 5029. Check tmp log /usr/local/mha/ha1/192.168.137.30_3306_20160826115742.log if it takes time..
Fri Aug 26 12:04:26 2016 - [info]
Fri Aug 26 12:04:26 2016 - [info] Log messages from 192.168.137.30 ...
Fri Aug 26 12:04:26 2016 - [info]
Fri Aug 26 12:04:25 2016 - [info] This server has all relay logs. No need to generate diff files from the latest slave.
Fri Aug 26 12:04:26 2016 - [info] End of log messages from 192.168.137.30.
Fri Aug 26 12:04:26 2016 - [info] -- 192.168.137.30(192.168.137.30:3306) has the latest relay log events.
Fri Aug 26 12:04:26 2016 - [info] Generating relay diff files from the latest slave succeeded.
Fri Aug 26 12:04:26 2016 - [info]
Fri Aug 26 12:04:26 2016 - [info] * Phase 4.2: Starting Parallel Slave Log Apply Phase..
Fri Aug 26 12:04:26 2016 - [info]
Fri Aug 26 12:04:26 2016 - [info] -- Slave recovery on host 192.168.137.30(192.168.137.30:3306) started, pid: 5031. Check tmp log /usr/local/mha/ha1/192.168.137.30_3306_20160826115742.log if it takes time..
Fri Aug 26 12:04:32 2016 - [info]
Fri Aug 26 12:04:32 2016 - [info] Log messages from 192.168.137.30 ...
Fri Aug 26 12:04:32 2016 - [info]
Fri Aug 26 12:04:26 2016 - [info] Sending binlog..
Fri Aug 26 12:04:28 2016 - [info] scp from local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog to [email protected]:/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog succeeded.
Fri Aug 26 12:04:28 2016 - [info] Starting recovery on 192.168.137.30(192.168.137.30:3306)..
Fri Aug 26 12:04:28 2016 - [info] Generating diffs succeeded.
Fri Aug 26 12:04:28 2016 - [info] Waiting until all relay logs are applied.
Fri Aug 26 12:04:28 2016 - [info] done.
Fri Aug 26 12:04:28 2016 - [info] Getting slave status..
Fri Aug 26 12:04:28 2016 - [info] This slave(192.168.137.30)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000074:22461852). No need to recover from Exec_Master_Log_Pos.
Fri Aug 26 12:04:28 2016 - [info] Connecting to the target slave host 192.168.137.30, running recover script..
Fri Aug 26 12:04:28 2016 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘root‘ --slave_host=192.168.137.30 --slave_ip=192.168.137.30 --slave_port=3306 --apply_files=/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog --workdir=/tmp --target_version=5.6.15-log --timestamp=20160826115742 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --slave_pass=xxx
Fri Aug 26 12:04:30 2016 - [info]
MySQL client version is 5.6.15. Using --binary-mode.
Applying differential binary/relay log files /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog on 192.168.137.30:3306. This may take long time...
Applying log files succeeded.
Fri Aug 26 12:04:30 2016 - [info] All relay logs were successfully applied.
Fri Aug 26 12:04:30 2016 - [info] Resetting slave 192.168.137.30(192.168.137.30:3306) and starting replication from the new master 192.168.137.10(192.168.137.10:3306)..
Fri Aug 26 12:04:31 2016 - [info] Executed CHANGE MASTER.
Fri Aug 26 12:04:31 2016 - [info] Slave started.
Fri Aug 26 12:04:32 2016 - [info] End of log messages from 192.168.137.30.
Fri Aug 26 12:04:32 2016 - [info] -- Slave recovery on host 192.168.137.30(192.168.137.30:3306) succeeded.
Fri Aug 26 12:04:32 2016 - [info] All new slave servers recovered successfully.
Fri Aug 26 12:04:32 2016 - [info]
Fri Aug 26 12:04:32 2016 - [info] * Phase 5: New master cleanup phase..
Fri Aug 26 12:04:32 2016 - [info]
Fri Aug 26 12:04:32 2016 - [info] Resetting slave info on the new master..
Fri Aug 26 12:04:32 2016 - [info] 192.168.137.10: Resetting slave info succeeded.
Fri Aug 26 12:04:32 2016 - [info] Master failover to 192.168.137.10(192.168.137.10:3306) completed successfully.
Fri Aug 26 12:04:32 2016 - [info]
----- Failover Report -----
ha1: MySQL Master failover 192.168.137.20 to 192.168.137.10 succeeded
Master 192.168.137.20 is down!
Check MHA Manager logs at monitor:/usr/local/mha/ha1/manager.log for details.
Started automated(non-interactive) failover.
Invalidated master IP address on 192.168.137.20.
The latest slave 192.168.137.30(192.168.137.30:3306) has all relay logs for recovery.
Selected 192.168.137.10 as a new master.
192.168.137.10: OK: Applying all logs succeeded.
192.168.137.10: OK: Activated master IP address.
192.168.137.30: This host has the latest relay log events.
Generating relay diff files from the latest slave succeeded.
192.168.137.30: OK: Applying all logs succeeded. Slave started, replicating from 192.168.137.10.
192.168.137.10: Resetting slave info succeeded.
Master failover to 192.168.137.10(192.168.137.10:3306) completed successfully.
说明：用红色标记了一些主要的处理过程，亮色加粗标记了每个步骤总共5个步骤
Failover步骤如下：
1.fail判断,分别判断dead master的mysql(Ping(SELECT))和ssh分别到达情况（之间会调用masterha_secondary_check脚本）→dead master处理阶段
2.配置文件检查，会检查整个集群配置文件配置（分别确定dead server,候选的master和所有的server的配置情况以及配置是否满足条件）→dead master处理阶段
3.宕机的master处理，包括虚拟ip摘除操作，主机关机操作（这里暂时没有配置关机操作）→dead master处理阶段
/usr/local/mha/ha1/fail_script/master_ip_failover --orig_master_host=192.168.137.20 --orig_master_ip=192.168.137.20 --orig_master_port=3306 --command=stopssh --ssh_user=root
4.找到含有最新relay log的slave(同时找到最旧的binlog的slave的position), 分别判断是否是候选的slave→new master还原阶段
5.保存dead master(137.20)和最新slave(137.30)相差的relay log保存在dead master的/tmp目录下（根据配置文件配置的remote_workdir）,然后确定这部分差异binlog（saved_master_binlog_）是否有效,也就是dead master和最新的slave之间是否存在binlog差异，存在差异则将生成的这个差异binlog拷贝到mha的workdir(137.40)下→new master还原阶段
Fri Aug 26 11:57:46 2016 - [info] Executing command on the dead master 192.168.137.20(192.168.137.20:3306): save_binary_logs --command=save --start_file=mysql-bin.000074 --start_pos=22461852 --binlog_dir=/mysql/log --output_file=/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 Creating /tmp if not exists.. ok. Concat binary/relay logs from mysql-bin.000074 pos 22461852 to mysql-bin.000074 EOF into /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog .. Dumping binlog format description event, from position 0 to 120.. ok. Dumping effective binlog data from /mysql/log/mysql-bin.000074 position 22461852 to tail(22497564).. ok. Concat succeeded. Fri Aug 26 11:57:49 2016 - [info] scp from [email protected]192.168.137.20:/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog to local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog succeeded.
7.确定新的master，并检查最新slave(30)的relay log是否可以用来还原其他的slave→new master还原阶段
8.生成最新slave(137.30)和new master(137.10)之间的差异relay log(在最新relay log的slave的/tmp下生成和其它slave差异的binlog，是二者的“Read_Master_Log_Pos”的差，取名为“relay_from_read_to_latest_后面紧接的是目标slave的ip”)，然后cp到目标（new master）的slave的/tmp下，同时将mha workdir下刚才保存的"saved_master_binlog_"(如果存在)文件拷贝到new master的/tmp下→new master还原阶段
Fri Aug 26 11:57:56 2016 - [info] Connecting to the latest slave host 192.168.137.30, generating diff relay log files..
Fri Aug 26 11:57:56 2016 - [info] Executing command: apply_diff_relay_logs --command=generate_and_send --scp_user=root --scp_host=192.168.137.10 --latest_mlf=mysql-bin.000074 --latest_rmlp=22461852 --target_mlf=mysql-bin.000074 --target_rmlp=9857376 --server_id=30 --diff_file_readtolatest=/tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog --workdir=/tmp --timestamp=20160826115742 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --relay_log_info=/mysql/data/relay-log.info --relay_dir=/mysql/data/
Fri Aug 26 11:58:02 2016 - [info]
Opening /mysql/data/relay-log.info ... ok.
Relay log found at /mysql/data, up to mysql-relay-bin.000003
Fast relay log position search succeeded.
Target relay log file/position found. start_file:mysql-relay-bin.000003, start_pos:9857539.
Concat binary/relay logs from mysql-relay-bin.000003 pos 9857539 to mysql-relay-bin.000003 EOF into /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog ..
Dumping binlog format description event, from position 0 to 283.. ok.
Dumping effective binlog data from /mysql/data/mysql-relay-bin.000003 position 9857539 to tail(22462015).. ok.
Concat succeeded.
Generating diff relay log succeeded. Saved at /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog .
scp slave:/tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog to [email protected]192.168.137.10(22) succeeded.
9.new master应用差异的relay log（首先会判断该salve原本Read_Master_Log_Pos”和“Exec_Master_Log_Pos是否相等，由于不是半同步复制所以slave虽然读到了该pos但是但是由于复制是异步的所有还得等待master定时发送binlog到slave，如果这中间master故障了就会导致二者的不一致)，如果不相等会在该slave执行save_binary_logs命令保存之间差异的relay log取名为“relay_from_exec_to_read_后面紧接的是自身的ip”；然后应用"relay_from_read_to_latest_、saved_master_binlog_、relay_from_exec_to_read_"这三个差异的relay log,同时将这三个文件的内容合并生成一个新的binlog文件“total_binlog_for_”→new master还原阶段
Fri Aug 26 12:00:06 2016 - [info] This slave(192.168.137.10)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000074:9857376). No need to recover from Exec_Master_Log_Pos. Fri Aug 26 12:00:06 2016 - [info] Connecting to the target slave host 192.168.137.10, running recover script.. Fri Aug 26 12:00:06 2016 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘root‘ --slave_host=192.168.137.10 --slave_ip=192.168.137.10 --slave_port=3306 --apply_files=/tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog,/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog --workdir=/tmp --target_version=5.6.15-log --timestamp=20160826115742 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --slave_pass=xxx Fri Aug 26 12:04:22 2016 - [info] Concat all apply files to /tmp/total_binlog_for_192.168.137.10_3306.20160826115742.binlog .. Copying the first binlog file /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog to /tmp/total_binlog_for_192.168.137.10_3306.20160826115742.binlog.. ok. Dumping binlog head events (rotate events), skipping format description events from /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog.. dumped up to pos 120. ok. /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog has effective binlog events from pos 120. Dumping effective binlog data from /tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog position 120 to tail(35832).. ok. Concat succeeded. All apply target binary logs are concatinated at /tmp/total_binlog_for_192.168.137.10_3306.20160826115742.binlog . MySQL client version is 5.6.15. Using --binary-mode. Applying differential binary/relay log files /tmp/relay_from_read_to_latest_192.168.137.10_3306_20160826115742.binlog,/tmp/saved_master_binlog_from_192.168.137.20_3306_20160826115742.binlog on 192.168.137.10:3306. This may take long time... Applying log files succeeded. Fri Aug 26 12:04:22 2016 - [info] All relay logs were successfully applied.
10.生成其它slave到新master的change语句，执行master_ip_failover完成切换生成VIP→new master还原阶段
11. 其它的slave也重复new masters slave的步骤 (从第8-9步，例如这里就会从mha的workdir拷贝saved_master_binlog_到最新的slave(137.30)上应用差异的relay log) →other slave还原阶段
12. other slave change new master→other slave还原阶段
13.生成failover report
注意：这里的relay log指的是slave已经读取到的master的binglog的位置(也就是slave中的relay log文件中已经保存了最新master binlog的位置)在show slave status \G中也就是“Read_Master_Log_Pos”并不是“Exec_Master_Log_Pos”，所以最新relay log的salve并不一定就是数据最新的（但是这种情况比较少），只能说明它保存的master binlog是最新的。
mha最先修复new master（不管它是否是最新的slave，所以如果候选的slave是最新的slave那么自然是最好的候选的slave就会很快修复好），然后再去修复其它的slave。
2.不在线手动Failover
注意：前提条件是mha没有启动，且存在dead的master，MHA manager检测到没有dead的server，将报错，并结束failover。
手动failover，这种场景意味着在业务上没有启用MHA自动切换功能，当主服务器故障时，人工手动调用MHA来进行故障切换操作，具体命令如下：
语句如下：
masterha_master_switch --master_state=dead --conf=/usr/local/mha/ha1/ha1.cnf --dead_master_host=192.168.137.10 --dead_master_port=3306 --new_master_host=192.168.137.20 --new_master_port=3306 --ignore_fail_on_start --ignore_last_failover
切换的过程中会存在几次需要输入“yes”进行下一步
[[email protected] ha1]# masterha_master_switch --master_state=dead --conf=/usr/local/mha/ha1/ha1.cnf --dead_master_host=192.168.137.10 --dead_master_port=3306 --new_master_host=192.168.137.20 --new_master_port=3306 --ignore_fail_on_start --ignore_last_failover --dead_master_ip=<dead_master_ip> is not set. Using 192.168.137.10. Fri Aug 26 17:44:10 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Fri Aug 26 17:44:10 2016 - [info] Reading application default configurations from /usr/local/mha/ha1/ha1.cnf.. Fri Aug 26 17:44:10 2016 - [info] Reading server configurations from /usr/local/mha/ha1/ha1.cnf.. Fri Aug 26 17:44:10 2016 - [info] MHA::MasterFailover version 0.55. Fri Aug 26 17:44:10 2016 - [info] Starting master failover. Fri Aug 26 17:44:10 2016 - [info] Fri Aug 26 17:44:10 2016 - [info] * Phase 1: Configuration Check Phase.. Fri Aug 26 17:44:10 2016 - [info] Fri Aug 26 17:44:11 2016 - [info] Dead Servers: Fri Aug 26 17:44:11 2016 - [info] 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:11 2016 - [info] Checking master reachability via mysql(double check).. Fri Aug 26 17:44:11 2016 - [info] ok. Fri Aug 26 17:44:11 2016 - [info] Alive Servers: Fri Aug 26 17:44:11 2016 - [info] 192.168.137.20(192.168.137.20:3306) Fri Aug 26 17:44:11 2016 - [info] 192.168.137.30(192.168.137.30:3306) Fri Aug 26 17:44:11 2016 - [info] Alive Slaves: Fri Aug 26 17:44:11 2016 - [info] 192.168.137.20(192.168.137.20:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Fri Aug 26 17:44:11 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:11 2016 - [info] Primary candidate for the new Master (candidate_master is set) Fri Aug 26 17:44:11 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Fri Aug 26 17:44:11 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:11 2016 - [info] Not candidate for the new Master (no_master is set) Master 192.168.137.10 is dead. Proceed? (yes/NO): yes Fri Aug 26 17:44:18 2016 - [info] ** Phase 1: Configuration Check Phase completed. Fri Aug 26 17:44:18 2016 - [info] Fri Aug 26 17:44:18 2016 - [info] * Phase 2: Dead Master Shutdown Phase.. Fri Aug 26 17:44:18 2016 - [info] Fri Aug 26 17:44:20 2016 - [info] HealthCheck: SSH to 192.168.137.10 is reachable. Fri Aug 26 17:44:22 2016 - [info] Forcing shutdown so that applications never connect to the current master.. Fri Aug 26 17:44:22 2016 - [info] Executing master IP deactivatation script: Fri Aug 26 17:44:22 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_failover --orig_master_host=192.168.137.10 --orig_master_ip=192.168.137.10 --orig_master_port=3306 --command=stopssh --ssh_user=root IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 192.168.137.50/24=== Disabling the VIP on old master: 192.168.137.10 Fri Aug 26 17:44:23 2016 - [info] done. Fri Aug 26 17:44:23 2016 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master. Fri Aug 26 17:44:23 2016 - [info] * Phase 2: Dead Master Shutdown Phase completed. Fri Aug 26 17:44:23 2016 - [info] Fri Aug 26 17:44:23 2016 - [info] * Phase 3: Master Recovery Phase.. Fri Aug 26 17:44:23 2016 - [info] Fri Aug 26 17:44:23 2016 - [info] * Phase 3.1: Getting Latest Slaves Phase.. Fri Aug 26 17:44:23 2016 - [info] Fri Aug 26 17:44:23 2016 - [info] The latest binary log file/position on all slaves is mysql-bin.000144:120 Fri Aug 26 17:44:23 2016 - [info] Latest slaves (Slaves that received relay log files to the latest): Fri Aug 26 17:44:23 2016 - [info] 192.168.137.20(192.168.137.20:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Fri Aug 26 17:44:23 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:23 2016 - [info] Primary candidate for the new Master (candidate_master is set) Fri Aug 26 17:44:23 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Fri Aug 26 17:44:23 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:23 2016 - [info] Not candidate for the new Master (no_master is set) Fri Aug 26 17:44:23 2016 - [info] The oldest binary log file/position on all slaves is mysql-bin.000144:120 Fri Aug 26 17:44:23 2016 - [info] Oldest slaves: Fri Aug 26 17:44:23 2016 - [info] 192.168.137.20(192.168.137.20:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Fri Aug 26 17:44:23 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:23 2016 - [info] Primary candidate for the new Master (candidate_master is set) Fri Aug 26 17:44:23 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Fri Aug 26 17:44:23 2016 - [info] Replicating from 192.168.137.10(192.168.137.10:3306) Fri Aug 26 17:44:23 2016 - [info] Not candidate for the new Master (no_master is set) Fri Aug 26 17:44:23 2016 - [info] Fri Aug 26 17:44:23 2016 - [info] * Phase 3.2: Saving Dead Master‘s Binlog Phase.. Fri Aug 26 17:44:23 2016 - [info] Fri Aug 26 17:44:24 2016 - [info] Fetching dead master‘s binary logs.. Fri Aug 26 17:44:24 2016 - [info] Executing command on the dead master 192.168.137.10(192.168.137.10:3306): save_binary_logs --command=save --start_file=mysql-bin.000144 --start_pos=120 --binlog_dir=/mysql/log --output_file=/tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 Creating /tmp if not exists.. ok. Concat binary/relay logs from mysql-bin.000144 pos 120 to mysql-bin.000144 EOF into /tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog .. Dumping binlog format description event, from position 0 to 120.. ok. Dumping effective binlog data from /mysql/log/mysql-bin.000144 position 120 to tail(143).. ok. Concat succeeded. saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog 100% 143 0.1KB/s 00:00 Fri Aug 26 17:44:27 2016 - [info] scp from [email protected]192.168.137.10:/tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog to local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog succeeded. Fri Aug 26 17:44:29 2016 - [info] HealthCheck: SSH to 192.168.137.20 is reachable. Fri Aug 26 17:44:31 2016 - [info] HealthCheck: SSH to 192.168.137.30 is reachable. Fri Aug 26 17:44:31 2016 - [info] Fri Aug 26 17:44:31 2016 - [info] * Phase 3.3: Determining New Master Phase.. Fri Aug 26 17:44:31 2016 - [info] Fri Aug 26 17:44:31 2016 - [info] Finding the latest slave that has all relay logs for recovering other slaves.. Fri Aug 26 17:44:31 2016 - [info] All slaves received relay logs to the same position. No need to resync each other. Fri Aug 26 17:44:31 2016 - [info] 192.168.137.20 can be new master. Fri Aug 26 17:44:31 2016 - [info] New master is 192.168.137.20(192.168.137.20:3306) Fri Aug 26 17:44:31 2016 - [info] Starting master failover.. Fri Aug 26 17:44:31 2016 - [info] From: 192.168.137.10 (current master) +--192.168.137.20 +--192.168.137.30 To: 192.168.137.20 (new master) +--192.168.137.30 Starting master switch from 192.168.137.10(192.168.137.10:3306) to 192.168.137.20(192.168.137.20:3306)? (yes/NO): yes Fri Aug 26 17:44:40 2016 - [info] New master decided manually is 192.168.137.20(192.168.137.20:3306) Fri Aug 26 17:44:40 2016 - [info] Fri Aug 26 17:44:40 2016 - [info] * Phase 3.3: New Master Diff Log Generation Phase.. Fri Aug 26 17:44:40 2016 - [info] Fri Aug 26 17:44:40 2016 - [info] This server has all relay logs. No need to generate diff files from the latest slave. Fri Aug 26 17:44:40 2016 - [info] Sending binlog.. saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog 100% 143 0.1KB/s 00:00 Fri Aug 26 17:44:42 2016 - [info] scp from local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog to [email protected]192.168.137.20:/tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog succeeded. Fri Aug 26 17:44:42 2016 - [info] Fri Aug 26 17:44:42 2016 - [info] * Phase 3.4: Master Log Apply Phase.. Fri Aug 26 17:44:42 2016 - [info] Fri Aug 26 17:44:42 2016 - [info] *NOTICE: If any error happens from this phase, manual recovery is needed. Fri Aug 26 17:44:42 2016 - [info] Starting recovery on 192.168.137.20(192.168.137.20:3306).. Fri Aug 26 17:44:42 2016 - [info] Generating diffs succeeded. Fri Aug 26 17:44:42 2016 - [info] Waiting until all relay logs are applied. Fri Aug 26 17:44:42 2016 - [info] done. Fri Aug 26 17:44:42 2016 - [info] Getting slave status.. Fri Aug 26 17:44:42 2016 - [info] This slave(192.168.137.20)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000144:120). No need to recover from Exec_Master_Log_Pos. Fri Aug 26 17:44:42 2016 - [info] Connecting to the target slave host 192.168.137.20, running recover script.. Fri Aug 26 17:44:42 2016 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘root‘ --slave_host=192.168.137.20 --slave_ip=192.168.137.20 --slave_port=3306 --apply_files=/tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog --workdir=/tmp --target_version=5.6.15-log --timestamp=20160826174410 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --slave_pass=xxx Fri Aug 26 17:44:43 2016 - [info] MySQL client version is 5.6.15. Using --binary-mode. Applying differential binary/relay log files /tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog on 192.168.137.20:3306. This may take long time... Applying log files succeeded. Fri Aug 26 17:44:43 2016 - [info] All relay logs were successfully applied. Fri Aug 26 17:44:43 2016 - [info] Getting new master‘s binlog name and position.. Fri Aug 26 17:44:43 2016 - [info] mysql-bin.000075:120 Fri Aug 26 17:44:43 2016 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.137.20‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000075‘, MASTER_LOG_POS=120, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘; Fri Aug 26 17:44:43 2016 - [info] Executing master IP activate script: Fri Aug 26 17:44:43 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_failover --command=start --ssh_user=root --orig_master_host=192.168.137.10 --orig_master_ip=192.168.137.10 --orig_master_port=3306 --new_master_host=192.168.137.20 --new_master_ip=192.168.137.20 --new_master_port=3306 --new_master_user=‘root‘ --new_master_password=‘root‘ IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 192.168.137.50/24=== Enabling the VIP - 192.168.137.50/24 on the new master - 192.168.137.20 Fri Aug 26 17:44:44 2016 - [info] OK. Fri Aug 26 17:44:44 2016 - [info] ** Finished master recovery successfully. Fri Aug 26 17:44:44 2016 - [info] * Phase 3: Master Recovery Phase completed. Fri Aug 26 17:44:44 2016 - [info] Fri Aug 26 17:44:44 2016 - [info] * Phase 4: Slaves Recovery Phase.. Fri Aug 26 17:44:44 2016 - [info] Fri Aug 26 17:44:44 2016 - [info] * Phase 4.1: Starting Parallel Slave Diff Log Generation Phase.. Fri Aug 26 17:44:44 2016 - [info] Fri Aug 26 17:44:44 2016 - [info] -- Slave diff file generation on host 192.168.137.30(192.168.137.30:3306) started, pid: 5354. Check tmp log /usr/local/mha/ha1/192.168.137.30_3306_20160826174410.log if it takes time.. Fri Aug 26 17:44:45 2016 - [info] Fri Aug 26 17:44:45 2016 - [info] Log messages from 192.168.137.30 ... Fri Aug 26 17:44:45 2016 - [info] Fri Aug 26 17:44:44 2016 - [info] This server has all relay logs. No need to generate diff files from the latest slave. Fri Aug 26 17:44:45 2016 - [info] End of log messages from 192.168.137.30. Fri Aug 26 17:44:45 2016 - [info] -- 192.168.137.30(192.168.137.30:3306) has the latest relay log events. Fri Aug 26 17:44:45 2016 - [info] Generating relay diff files from the latest slave succeeded. Fri Aug 26 17:44:45 2016 - [info] Fri Aug 26 17:44:45 2016 - [info] * Phase 4.2: Starting Parallel Slave Log Apply Phase.. Fri Aug 26 17:44:45 2016 - [info] Fri Aug 26 17:44:45 2016 - [info] -- Slave recovery on host 192.168.137.30(192.168.137.30:3306) started, pid: 5356. Check tmp log /usr/local/mha/ha1/192.168.137.30_3306_20160826174410.log if it takes time.. saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog 100% 143 0.1KB/s 00:00 Fri Aug 26 17:44:47 2016 - [info] Fri Aug 26 17:44:47 2016 - [info] Log messages from 192.168.137.30 ... Fri Aug 26 17:44:47 2016 - [info] Fri Aug 26 17:44:45 2016 - [info] Sending binlog.. Fri Aug 26 17:44:45 2016 - [info] scp from local:/usr/local/mha/ha1/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog to [email protected]192.168.137.30:/tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog succeeded. Fri Aug 26 17:44:45 2016 - [info] Starting recovery on 192.168.137.30(192.168.137.30:3306).. Fri Aug 26 17:44:45 2016 - [info] Generating diffs succeeded. Fri Aug 26 17:44:45 2016 - [info] Waiting until all relay logs are applied. Fri Aug 26 17:44:45 2016 - [info] done. Fri Aug 26 17:44:45 2016 - [info] Getting slave status.. Fri Aug 26 17:44:45 2016 - [info] This slave(192.168.137.30)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000144:120). No need to recover from Exec_Master_Log_Pos. Fri Aug 26 17:44:45 2016 - [info] Connecting to the target slave host 192.168.137.30, running recover script.. Fri Aug 26 17:44:45 2016 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘root‘ --slave_host=192.168.137.30 --slave_ip=192.168.137.30 --slave_port=3306 --apply_files=/tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog --workdir=/tmp --target_version=5.6.15-log --timestamp=20160826174410 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.55 --slave_pass=xxx Fri Aug 26 17:44:45 2016 - [info] MySQL client version is 5.6.15. Using --binary-mode. Applying differential binary/relay log files /tmp/saved_master_binlog_from_192.168.137.10_3306_20160826174410.binlog on 192.168.137.30:3306. This may take long time... Applying log files succeeded. Fri Aug 26 17:44:45 2016 - [info] All relay logs were successfully applied. Fri Aug 26 17:44:45 2016 - [info] Resetting slave 192.168.137.30(192.168.137.30:3306) and starting replication from the new master 192.168.137.20(192.168.137.20:3306).. Fri Aug 26 17:44:46 2016 - [info] Executed CHANGE MASTER. Fri Aug 26 17:44:46 2016 - [info] Slave started. Fri Aug 26 17:44:47 2016 - [info] End of log messages from 192.168.137.30. Fri Aug 26 17:44:47 2016 - [info] -- Slave recovery on host 192.168.137.30(192.168.137.30:3306) succeeded. Fri Aug 26 17:44:47 2016 - [info] All new slave servers recovered successfully. Fri Aug 26 17:44:47 2016 - [info] Fri Aug 26 17:44:47 2016 - [info] * Phase 5: New master cleanup phase.. Fri Aug 26 17:44:47 2016 - [info] Fri Aug 26 17:44:47 2016 - [info] Resetting slave info on the new master.. Fri Aug 26 17:44:47 2016 - [info] 192.168.137.20: Resetting slave info succeeded. Fri Aug 26 17:44:47 2016 - [info] Master failover to 192.168.137.20(192.168.137.20:3306) completed successfully. Fri Aug 26 17:44:47 2016 - [info] ----- Failover Report ----- ha1: MySQL Master failover 192.168.137.10 to 192.168.137.20 succeeded Master 192.168.137.10 is down! Check MHA Manager logs at monitor for details. Started manual(interactive) failover. Invalidated master IP address on 192.168.137.10. The latest slave 192.168.137.20(192.168.137.20:3306) has all relay logs for recovery. Selected 192.168.137.20 as a new master. 192.168.137.20: OK: Applying all logs succeeded. 192.168.137.20: OK: Activated master IP address. 192.168.137.30: This host has the latest relay log events. Generating relay diff files from the latest slave succeeded. 192.168.137.30: OK: Applying all logs succeeded. Slave started, replicating from 192.168.137.20. 192.168.137.20: Resetting slave info succeeded. Master failover to 192.168.137.20(192.168.137.20:3306) completed successfully.
3.在线手动Failover
在许多情况下， 需要将现有的主服务器迁移到另外一台服务器上。 比如主服务器硬件故障，RAID 控制卡需要重建，将主服务器移到性能更好的服务器上等等。维护主服务器引起性能下降， 导致停机时间至少无法写入数据。 另外， 阻塞或杀掉当前运行的会话会导致主主之间数据不一致的问题发生。 MHA 提供快速切换和优雅的阻塞写入，这个切换过程只需要 0.5-2s 的时间，这段时间内数据是无法写入的。在很多情况下，0.5-2s 的阻塞写入是可以接受的。因此切换主服务器不需要计划分配维护时间窗口。
MHA在线切换的大概过程：
1.检测复制设置和确定当前主服务器
2.确定新的主服务器
3.阻塞写入到当前主服务器
4.等待所有从服务器赶上复制
5.授予写入到新的主服务器
6.重新设置从服务器
注意，在线切换的时候应用架构需要考虑以下两个问题：
1.自动识别master和slave的问题（master的机器可能会切换），如果采用了vip的方式，基本可以解决这个问题。
2.负载均衡的问题（可以定义大概的读写比例，每台机器可承担的负载比例，当有机器离开集群时，需要考虑这个问题）
为了保证数据完全一致性，在最快的时间内完成切换，MHA的在线切换必须满足以下条件才会切换成功，否则会切换失败。
1.所有slave的IO线程都在运行
2.所有slave的SQL线程都在运行
3.所有的show slave status的输出中Seconds_Behind_Master参数小于或者等于running_updates_limit秒，如果在切换过程中不指定running_updates_limit,那么默认情况下running_updates_limit为1秒。
4.在old master端，通过show processlist输出，没有一个更新花费的时间大于running_updates_limit秒。
1.首先，停掉MHA监控：
masterha_stop --conf=/usr/local/mha/ha1/ha1.cnf
2.手动在线failover
新的master为192.168.137.10
masterha_master_switch --conf=/usr/local/mha/ha1/ha1.cnf --master_state=alive --new_master_host=192.168.137.10 --new_master_port=3306 --orig_master_is_new_slave --running_updates_limit=10000
--orig_master_is_new_slave 切换时加上此参数是将原 master 变为 slave 节点，如果不加此参数，原来的 master 将不启动
--running_updates_limit=10000,故障切换时,候选master 如果有延迟的话， mha 切换不能成功，加上此参数表示延迟在此时间范围内都可切换（单位为s），但是切换的时间长短是由recover 时relay 日志的大小决定
注意：手动在线用的failover脚本是“master_ip_online_change”
3.切换日志
[root@monitor fail_script]# masterha_master_switch --conf=/usr/local/mha/ha1/ha1.cnf --master_state=alive --new_master_host=192.168.137.10 --new_master_port=3306 --orig_master_is_new_slave --running_updates_limit=10000 Mon Aug 29 10:41:37 2016 - [info] MHA::MasterRotate version 0.55. Mon Aug 29 10:41:37 2016 - [info] Starting online master switch.. Mon Aug 29 10:41:37 2016 - [info] Mon Aug 29 10:41:37 2016 - [info] * Phase 1: Configuration Check Phase.. Mon Aug 29 10:41:37 2016 - [info] Mon Aug 29 10:41:37 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Mon Aug 29 10:41:37 2016 - [info] Reading application default configurations from /usr/local/mha/ha1/ha1.cnf.. Mon Aug 29 10:41:37 2016 - [info] Reading server configurations from /usr/local/mha/ha1/ha1.cnf.. Mon Aug 29 10:41:38 2016 - [info] Current Alive Master: 192.168.137.20(192.168.137.20:3306) Mon Aug 29 10:41:38 2016 - [info] Alive Slaves: Mon Aug 29 10:41:38 2016 - [info] 192.168.137.10(192.168.137.10:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Mon Aug 29 10:41:38 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306) Mon Aug 29 10:41:38 2016 - [info] Primary candidate for the new Master (candidate_master is set) Mon Aug 29 10:41:38 2016 - [info] 192.168.137.30(192.168.137.30:3306) Version=5.6.15-log (oldest major version between slaves) log-bin:enabled Mon Aug 29 10:41:38 2016 - [info] Replicating from 192.168.137.20(192.168.137.20:3306) Mon Aug 29 10:41:38 2016 - [info] Not candidate for the new Master (no_master is set) It is better to execute FLUSH NO_WRITE_TO_BINLOG TABLES on the master before switching. Is it ok to execute on 192.168.137.20(192.168.137.20:3306)? (YES/no): yes Mon Aug 29 10:41:40 2016 - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time.. Mon Aug 29 10:41:40 2016 - [info] ok. Mon Aug 29 10:41:40 2016 - [info] Checking MHA is not monitoring or doing failover.. Mon Aug 29 10:41:40 2016 - [info] Checking replication health on 192.168.137.10.. Mon Aug 29 10:41:40 2016 - [info] ok. Mon Aug 29 10:41:40 2016 - [info] Checking replication health on 192.168.137.30.. Mon Aug 29 10:41:40 2016 - [info] ok. Mon Aug 29 10:41:40 2016 - [info] 192.168.137.10 can be new master. Mon Aug 29 10:41:40 2016 - [info] From: 192.168.137.20 (current master) +--192.168.137.10 +--192.168.137.30 To: 192.168.137.10 (new master) +--192.168.137.30 +--192.168.137.20 Starting master switch from 192.168.137.20(192.168.137.20:3306) to 192.168.137.10(192.168.137.10:3306)? (yes/NO): yes Mon Aug 29 10:41:42 2016 - [info] Checking whether 192.168.137.10(192.168.137.10:3306) is ok for the new master.. Mon Aug 29 10:41:42 2016 - [info] ok. Mon Aug 29 10:41:42 2016 - [info] 192.168.137.20(192.168.137.20:3306): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host. Mon Aug 29 10:41:42 2016 - [info] 192.168.137.20(192.168.137.20:3306): Resetting slave pointing to the dummy host. Mon Aug 29 10:41:42 2016 - [info] ** Phase 1: Configuration Check Phase completed. Mon Aug 29 10:41:42 2016 - [info] Mon Aug 29 10:41:42 2016 - [info] * Phase 2: Rejecting updates Phase.. Mon Aug 29 10:41:42 2016 - [info] Mon Aug 29 10:41:42 2016 - [info] Executing master ip online change script to disable write on the current master: Mon Aug 29 10:41:42 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_online_change --command=stop --orig_master_host=192.168.137.20 --orig_master_ip=192.168.137.20 --orig_master_port=3306 --orig_master_user=‘root‘ --orig_master_password=‘root‘ --new_master_host=192.168.137.10 --new_master_ip=192.168.137.10 --new_master_port=3306 --new_master_user=‘root‘ --new_master_password=‘root‘ *************************************************************** Disabling the VIP - 192.168.137.50/24 on old master: 192.168.137.20 *************************************************************** Mon Aug 29 10:41:43 2016 - [info] ok. Mon Aug 29 10:41:43 2016 - [info] Locking all tables on the orig master to reject updates from everybody (including root): Mon Aug 29 10:41:43 2016 - [info] Executing FLUSH TABLES WITH READ LOCK.. Mon Aug 29 10:41:43 2016 - [info] ok. Mon Aug 29 10:41:43 2016 - [info] Orig master binlog:pos is mysql-bin.000076:120. Mon Aug 29 10:41:43 2016 - [info] Waiting to execute all relay logs on 192.168.137.10(192.168.137.10:3306).. Mon Aug 29 10:41:43 2016 - [info] master_pos_wait(mysql-bin.000076:120) completed on 192.168.137.10(192.168.137.10:3306). Executed 0 events. Mon Aug 29 10:41:43 2016 - [info] done. Mon Aug 29 10:41:43 2016 - [info] Getting new master‘s binlog name and position.. Mon Aug 29 10:41:43 2016 - [info] mysql-bin.000147:120 Mon Aug 29 10:41:43 2016 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.137.10‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000147‘, MASTER_LOG_POS=120, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘; Mon Aug 29 10:41:43 2016 - [info] Executing master ip online change script to allow write on the new master: Mon Aug 29 10:41:43 2016 - [info] /usr/local/mha/ha1/fail_script/master_ip_online_change --command=start --orig_master_host=192.168.137.20 --orig_master_ip=192.168.137.20 --orig_master_port=3306 --orig_master_user=‘root‘ --orig_master_password=‘root‘ --new_master_host=192.168.137.10 --new_master_ip=192.168.137.10 --new_master_port=3306 --new_master_user=‘root‘ --new_master_password=‘root‘ *************************************************************** Enabling the VIP - 192.168.137.50/24 on new master: 192.168.137.10 *************************************************************** Mon Aug 29 10:41:44 2016 - [info] ok. Mon Aug 29 10:41:44 2016 - [info] Mon Aug 29 10:41:44 2016 - [info] * Switching slaves in parallel.. Mon Aug 29 10:41:44 2016 - [info] Mon Aug 29 10:41:44 2016 - [info] -- Slave switch on host 192.168.137.30(192.168.137.30:3306) started, pid: 4371 Mon Aug 29 10:41:44 2016 - [info] Mon Aug 29 10:41:45 2016 - [info] Log messages from 192.168.137.30 ... Mon Aug 29 10:41:45 2016 - [info] Mon Aug 29 10:41:44 2016 - [info] Waiting to execute all relay logs on 192.168.137.30(192.168.137.30:3306).. Mon Aug 29 10:41:44 2016 - [info] master_pos_wait(mysql-bin.000076:120) completed on 192.168.137.30(192.168.137.30:3306). Executed 0 events. Mon Aug 29 10:41:44 2016 - [info] done. Mon Aug 29 10:41:44 2016 - [info] Resetting slave 192.168.137.30(192.168.137.30:3306) and starting replication from the new master 192.168.137.10(192.168.137.10:3306).. Mon Aug 29 10:41:44 2016 - [info] Executed CHANGE MASTER. Mon Aug 29 10:41:44 2016 - [info] Slave started. Mon Aug 29 10:41:45 2016 - [info] End of log messages from 192.168.137.30 ... Mon Aug 29 10:41:45 2016 - [info] Mon Aug 29 10:41:45 2016 - [info] -- Slave switch on host 192.168.137.30(192.168.137.30:3306) succeeded. Mon Aug 29 10:41:45 2016 - [info] Unlocking all tables on the orig master: Mon Aug 29 10:41:45 2016 - [info] Executing UNLOCK TABLES.. Mon Aug 29 10:41:45 2016 - [info] ok. Mon Aug 29 10:41:45 2016 - [info] Starting orig master as a new slave.. Mon Aug 29 10:41:45 2016 - [info] Resetting slave 192.168.137.20(192.168.137.20:3306) and starting replication from the new master 192.168.137.10(192.168.137.10:3306).. Mon Aug 29 10:41:45 2016 - [info] Executed CHANGE MASTER. Mon Aug 29 10:41:45 2016 - [info] Slave started. Mon Aug 29 10:41:45 2016 - [info] All new slave servers switched successfully. Mon Aug 29 10:41:45 2016 - [info] Mon Aug 29 10:41:45 2016 - [info] * Phase 5: New master cleanup phase.. Mon Aug 29 10:41:45 2016 - [info] Mon Aug 29 10:41:45 2016 - [info] 192.168.137.10: Resetting slave info succeeded. Mon Aug 29 10:41:45 2016 - [info] Switching master to 192.168.137.10(192.168.137.10:3306) completed successfully.
切换失败：
[error][/usr/local/share/perl5/MHA/MasterRotate.pm, ln262] We should not start online master switch when one of connections are running long queries on the new master(192.168.137.10(192.168.137.10:3306)). Currently 1 thread(s) are running.
Details:
{‘Time‘ => ‘1173‘,‘Command‘ => ‘Daemon‘,‘db‘ => undef,‘Id‘ => ‘3‘,‘Info‘ => undef,‘User‘ => ‘event_scheduler‘,‘State‘ => ‘Waiting on empty queue‘,‘Host‘ => ‘localhost‘}
从错误信息已经说的非常的清除，在new master中存在一个long queries,且该线程的id=3是一个事件调度线程，由于new master我开启了“scheduler”导致了在线手动切换失败，我把“scheduler”关闭就成功了。
在MHA的环境中备选的Master不能开启“scheduler”
参考：
http://www.cnblogs.com/gomysql/p/3675429.html
http://blog.csdn.net/lichangzai/article/details/50470771
mha下载地址：
https://mysql-master-ha.googlecode.com/files/mha4mysql-manager-0.55.tar.gz
https://mysql-master-ha.googlecode.com/files/mha4mysql-node-0.54.tar.gz
之前写的复制相关文章：
主从复制：http://www.cnblogs.com/chenmh/p/5089919.html
主主复制：http://www.cnblogs.com/chenmh/p/5153184.html
MMM方案：http://www.cnblogs.com/chenmh/p/5563778.html
半同步复制与MMM:http://www.cnblogs.com/chenmh/p/5744227.html
总结
主和备主之间需要半同步复制才能保证mha的最大程度的数据不丢失，否则使用MHA也就没优势了；还有就主和备主不要开启scheduler(作业)，否则手动在线failover会失败。mha最先修复new master（不管它是否是最新的slave，所以如果候选的slave是最新的slave那么自然是最好的候选的slave就会很快修复好），然后再去修复其它的slave。
注意：文章中对一些配置做了备注说明，在实际部署中需要将这些备注删掉
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时间： 2024-10-10 05:38:39