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，它由日本DeNA公司youshimaton（现就职于Facebook公司）开发，
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。
该软件由两部分组成：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。
目前MHA主要支持一主多从的架构，要搭建MHA,要求一个复制集群中必须最少有三台数据库服务器，一主二从，即一台充当master，一台充当备用master，
另外一台充当从库，因为至少需要三台服务器，出于机器成本的考虑，淘宝也在该基础上进行了改造，目前淘宝TMHA已经支持一主一从。
官方介绍：https://code.google.com/p/mysql-master-ha/
下图展示了如何通过MHA Manager管理多组主从复制。可以将MHA工作原理总结为如下
本次环境规划如下 (centos6.7)
1、配置三台服务器ssh互信 ssh-keygen -t rsa 一路回车即可 Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /root/.ssh/id_rsa. Your public key has been saved in /root/.ssh/id_rsa.pub. The key fingerprint is: c7:2e:ca:e2:c2:3b:30:63:97:b4:62:81:dd:27:e3:f9 [email protected] The key‘s randomart image is: +--[ RSA 2048]----+ | | | | |.. . | |....+ . . | | o.o= S o | |++ +o o | |o=o . . . | | + ..E. . | | .=..o | +-----------------+ [[email protected] mysql]#ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected] [[email protected] mysql]#ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected] [[email protected] mysql]# ssh-copy-id -i /root/.ssh/id_rsa.pub 172.16.80.127 The authenticity of host ‘172.16.80.127 (172.16.80.127)‘ can‘t be established. RSA key fingerprint is 05:89:5e:3d:2a:c1:ae:90:27:d9:a5:48:4a:ab:b9:79. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added ‘172.16.80.127‘ (RSA) to the list of known hosts. [email protected]‘s password: Now try logging into the machine, with "ssh ‘172.16.80.127‘", and check in: .ssh/authorized_keys to make sure we haven‘t added extra keys that you weren‘t expecting. 测试 [[email protected] mysql]# ssh 172.16.80.117 ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:0C:29:45:FE:30 inet addr:172.16.80.117 Bcast:172.16.80.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fe45:fe30/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1220176 errors:0 dropped:0 overruns:0 frame:0 TX packets:980887 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1198343068 (1.1 GiB) TX bytes:1318688106 (1.2 GiB) [[email protected] mysql]# ssh 172.16.80.127 ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:0C:29:FF:58:D9 inet addr:172.16.80.127 Bcast:172.16.80.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feff:58d9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:162129 errors:0 dropped:0 overruns:0 frame:0 TX packets:27546 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:225287420 (214.8 MiB) TX bytes:1921228 (1.8 MiB) 2、三节点配置epel的yum源，安装相关依赖包 rpm -Uvh rpm --import/etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6 yum -y install perl-DBD-MySQL ncftp 在3个mysql节点做授权配置 mysql> grant replication slave on *.* to ‘martin‘@‘172.16.80.%‘ identified by ‘123456‘; Query OK, 0 rows affected (0.05 sec) mysql> grant all on *.* to ‘root‘@‘172.16.80.%‘ identified by ‘123456‘; Query OK, 0 rows affected (0.00 sec)
查看主节点上的日志状态mysql> show master status; mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000001 | 107 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.01 sec)
3、在两个从节点上面执行如下操作 change master to master_host=‘172.16.80.117‘,master_user=‘martin‘,master_password=‘123456‘,master_log_file=‘mysql-bin.000001‘,master_log_pos=107; mysql> start slave; Query OK, 0 rows affected (0.06 sec) mysql> show slave status \G; 可以看到主从同步状态正常
4、安装MHA软件MHA提供了源码和rpm包两种安装方式，如果是rpm包安装，方式如下： 1）在三个节点依次安装MHA的node [[email protected] tools]# rpm -ivh mha4mysql-node-0.56-0.el6.noarch.rpm Preparing...########################################### [100%] 1:mha4mysql-node ########################################### [100%] 2）最后在Slave/MHA Manager节点安装mha4mysql-manage： yum install perl-Parallel-ForkManager perl-Time-HiRes \ perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch \ perl-Parallel-ForkManagerperl-Config-IniFilesperl-Time-HiRes [[email protected] tools]# rpm -ivh mha4mysql-manager-0.56-0.el6.noarch.rpm Preparing...########################################### [100%] 1:mha4mysql-manager ########################################### [100%] [[email protected] tools]# mkdir -p /etc/mha/scripts
1、通过masterha_check_ssh验证ssh信任登录是否成功，
[[email protected] scripts]# masterha_check_ssh --conf=/etc/mha/app1.cnf
Thu Aug 11 19:29:03 2016 - [info] Reading default configuration from /etc/masterha_default.cnf..
Thu Aug 11 19:29:03 2016 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Thu Aug 11 19:29:03 2016 - [info] Reading server configuration from /etc/mha/app1.cnf..
Thu Aug 11 19:29:03 2016 - [info] Starting SSH connection tests..
Thu Aug 11 19:29:04 2016 - [debug]
Thu Aug 11 19:29:03 2016 - [debug] Connecting via SSH from [email protected](172.16.80.117:22) to [email protected](172.16.80.127:22)..
Thu Aug 11 19:29:03 2016 - [debug] ok.
Thu Aug 11 19:29:03 2016 - [debug] Connecting via SSH from [email protected](172.16.80.117:22) to [email protected](172.16.80.128:22)..
Thu Aug 11 19:29:04 2016 - [debug] ok.
Thu Aug 11 19:29:04 2016 - [debug]
Thu Aug 11 19:29:03 2016 - [debug] Connecting via SSH from [email protected](172.16.80.127:22) to [email protected](172.16.80.117:22)..
Thu Aug 11 19:29:04 2016 - [debug] ok.
Thu Aug 11 19:29:04 2016 - [debug] Connecting via SSH from [email protected](172.16.80.127:22) to [email protected](172.16.80.128:22)..
Thu Aug 11 19:29:04 2016 - [debug] ok.
Thu Aug 11 19:29:04 2016 - [debug]
Thu Aug 11 19:29:04 2016 - [debug] Connecting via SSH from [email protected](172.16.80.128:22) to [email protected](172.16.80.117:22)..
Thu Aug 11 19:29:04 2016 - [debug] ok.
Thu Aug 11 19:29:04 2016 - [debug] Connecting via SSH from [email protected](172.16.80.128:22) to [email protected](172.16.80.127:22)..
Thu Aug 11 19:29:04 2016 - [debug] ok.
Thu Aug 11 19:29:04 2016 - [info] All SSH connection tests passed successfully.
2、masterha_check_repl验证mysql复制是否成功
masterha_check_repl --conf=/etc/mha/app1.cnf
[[email protected] scripts]# masterha_check_repl --conf=/etc/mha/app1.cnf
Thu Aug 11 19:31:53 2016 - [info] Reading default configuration from /etc/masterha_default.cnf..
Thu Aug 11 19:31:53 2016 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Thu Aug 11 19:31:53 2016 - [info] Reading server configuration from /etc/mha/app1.cnf..
Thu Aug 11 19:31:53 2016 - [info] MHA::MasterMonitor version 0.56.
Thu Aug 11 19:31:54 2016 - [info] GTID failover mode = 0
Thu Aug 11 19:31:54 2016 - [info] Dead Servers:
Thu Aug 11 19:31:54 2016 - [info] Alive Servers:
Thu Aug 11 19:31:54 2016 - [info] 172.16.80.117(172.16.80.117:3306)
Thu Aug 11 19:31:54 2016 - [info] 172.16.80.127(172.16.80.127:3306)
Thu Aug 11 19:31:54 2016 - [info] 172.16.80.128(172.16.80.128:3306)
Thu Aug 11 19:31:54 2016 - [info] Alive Slaves:
Thu Aug 11 19:31:54 2016 - [info] 172.16.80.127(172.16.80.127:3306) Version=5.5.49-log (oldest major version between slaves) log-bin:enabled
Thu Aug 11 19:31:54 2016 - [info] Replicating from 172.16.80.117(172.16.80.117:3306)
Thu Aug 11 19:31:54 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Thu Aug 11 19:31:54 2016 - [info] 172.16.80.128(172.16.80.128:3306) Version=5.5.49-log (oldest major version between slaves) log-bin:enabled
Thu Aug 11 19:31:54 2016 - [info] Replicating from 172.16.80.117(172.16.80.117:3306)
Thu Aug 11 19:31:54 2016 - [info] Not candidate for the new Master (no_master is set)
Thu Aug 11 19:31:54 2016 - [info] Current Alive Master: 172.16.80.117(172.16.80.117:3306)
Thu Aug 11 19:31:54 2016 - [info] Checking slave configurations..
Thu Aug 11 19:31:54 2016 - [warning] relay_log_purge=0 is not set on slave 172.16.80.127(172.16.80.127:3306).
Thu Aug 11 19:31:54 2016 - [warning] relay_log_purge=0 is not set on slave 172.16.80.128(172.16.80.128:3306).
Thu Aug 11 19:31:54 2016 - [info] Checking replication filtering settings..
Thu Aug 11 19:31:54 2016 - [info] binlog_do_db= , binlog_ignore_db=
Thu Aug 11 19:31:54 2016 - [info] Replication filtering check ok.
Thu Aug 11 19:31:54 2016 - [info] GTID (with auto-pos) is not supported
Thu Aug 11 19:31:54 2016 - [info] Starting SSH connection tests..
Thu Aug 11 19:31:56 2016 - [info] All SSH connection tests passed successfully.
Thu Aug 11 19:31:56 2016 - [info] Checking MHA Node version..
Thu Aug 11 19:31:56 2016 - [info] Version check ok.
Thu Aug 11 19:31:56 2016 - [info] Checking SSH publickey authentication settings on the current master..
Thu Aug 11 19:31:57 2016 - [info] HealthCheck: SSH to 172.16.80.117 is reachable.
Thu Aug 11 19:31:57 2016 - [info] Master MHA Node version is 0.56.
Thu Aug 11 19:31:57 2016 - [info] Checking recovery script configurations on 172.16.80.117(172.16.80.117:3306)..
Thu Aug 11 19:31:57 2016 - [info] Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/application/mysql/data --output_file=/var/tmp/save_binary_logs_test --manager_version=0.56 --start_file=mysql-bin.000001
Thu Aug 11 19:31:57 2016 - [info] Connecting to [email protected](172.16.80.117:22)..
Creating /var/tmp if not exists.. ok.
Checking output directory is accessible or not..
ok.
Binlog found at /application/mysql/data, up to mysql-bin.000001
Thu Aug 11 19:31:57 2016 - [info] Binlog setting check done.
Thu Aug 11 19:31:57 2016 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Thu Aug 11 19:31:57 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user=‘root‘ --slave_host=172.16.80.127 --slave_ip=172.16.80.127 --slave_port=3306 --workdir=/var/tmp --target_version=5.5.49-log --manager_version=0.56 --relay_log_info=/application/mysql/data/relay-log.info --relay_dir=/application/mysql/data/ --slave_pass=xxx
Thu Aug 11 19:31:57 2016 - [info] Connecting to [email protected](172.16.80.127:22)..
Checking slave recovery environment settings..
Opening /application/mysql/data/relay-log.info ... ok.
Relay log found at /application/mysql/data, up to mysql-relay-bin.000002
Temporary relay log file is /application/mysql/data/mysql-relay-bin.000002
Testing mysql connection and privileges.. done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Thu Aug 11 19:31:58 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user=‘root‘ --slave_host=172.16.80.128 --slave_ip=172.16.80.128 --slave_port=3306 --workdir=/var/tmp --target_version=5.5.49-log --manager_version=0.56 --relay_log_info=/application/mysql/data/relay-log.info --relay_dir=/application/mysql/data/ --slave_pass=xxx
Thu Aug 11 19:31:58 2016 - [info] Connecting to [email protected](172.16.80.128:22)..
Checking slave recovery environment settings..
Opening /application/mysql/data/relay-log.info ... ok.
Relay log found at /application/mysql/data, up to mysql-relay-bin.000002
Temporary relay log file is /application/mysql/data/mysql-relay-bin.000002
Testing mysql connection and privileges.. done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Thu Aug 11 19:31:58 2016 - [info] Slaves settings check done.
Thu Aug 11 19:31:58 2016 - [info]
172.16.80.117(172.16.80.117:3306) (current master)
+--172.16.80.127(172.16.80.127:3306)
+--172.16.80.128(172.16.80.128:3306)
Thu Aug 11 19:31:58 2016 - [info] Checking replication health on 172.16.80.127..
Thu Aug 11 19:31:58 2016 - [info] ok.
Thu Aug 11 19:31:58 2016 - [info] Checking replication health on 172.16.80.128..
Thu Aug 11 19:31:58 2016 - [info] ok.
Thu Aug 11 19:31:58 2016 - [info] Checking master_ip_failover_script status:
Thu Aug 11 19:31:58 2016 - [info] /etc/mha/scripts/master_ip_failover --command=status --ssh_user=root --orig_master_host=172.16.80.117 --orig_master_ip=172.16.80.117 --orig_master_port=3306
IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 172.16.80.200/24===
Checking the Status of the script.. OK
Thu Aug 11 19:31:58 2016 - [info] OK.
Thu Aug 11 19:31:58 2016 - [warning] shutdown_script is not defined.
Thu Aug 11 19:31:58 2016 - [info] Got exit code 0 (Not master dead).
MySQL Replication Health is OK.
准备failover脚本用于vip切换
[[email protected] ~]# cat /etc/mha/scripts/master_ip_failover
#!/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
);
my $vip = ‘172.16.80.200/24‘;
my $key = ‘1‘;
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,
);
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";
}
启动MHA
先执行如下命令：
/sbin/ifconfig eth0:1 172.16.80.200（只需第一次添加）
将vip绑定到目前的master上。
然后通过masterha_manager启动MHA监控：
[[email protected] scripts]# mkdir /var/log//masterha/app1 -p
[[email protected] scripts]# touch /var/log/masterha/app1/manager.log
[[email protected] scripts]# nohup masterha_manager --conf=/etc/mha/app1.cnf --remove_dead_master_conf--ignore_last_failover< /dev/null > \
/var/log/masterha/app1/manager.log 2>&1 &
然后通过masterha_check_status查看MHA状态
[[email protected] scripts]# masterha_check_status --conf=/etc/mha/app1.cnf
app1 (pid:58184) is running(0:PING_OK), master:172.16.80.117
模拟主库 172.16.80.117 数据库挂掉
[[email protected] .ssh]# /etc/init.d/mysqld stop
Shutting down MySQL................ [ OK ]
可以看到这个从库自动连接到了新的主库 172.16.80.127上面
切换完成后，关注如下变化： 1、 vip自动从原来的master切换到新的master，同时，manager节点的监控进程自动退出。 2、 在日志目录（/var/log/masterha/app1）产生一个app1.failover.complete文件 3、 /etc/mha/app1.cnf配置文件中原来老的master配置被删除。
再截图之前ssh及mysql主从检查的过程
时间： 2024-10-04 11:24:06