前言：
上回讲到，《lvs-dr模型负载均衡高可用Discuz》，但是由于lvs过于重量级，小公司使用有点不合时宜，本回咱们使用nginx实现此功能。望各位博友笑纳。
此次试验使用nginx代替lvs作为前端调度器，使用keepalived对nginx做双主模型高可用，向后做反向代理。RS服务器使用httpd+php来处理php页面请求，httpd和php以模块形式结合。暂时不考虑会话保持和动静资源分离的问题。我们下一篇博客会做补充。一次写太多会影响品质！！！
规划：
前端使用两台nginx服务器作为前端调度器，使用keepalived对nginx做双主模型高可用，两台RS服务器，后端一台共享存储提供mariadb和NFS服务，因为不再使用LVS调度，而是通过nginx反代来实现，所以两台RS服务器不需要在本地回环接口的别名上配置VIP
各个主机的IP地址
Host VS1
eno16777736 10.0.0.201/8 (DIP)
gateway: 10.0.0.254
Host VS2
eno16777736 10.0.0.203/8(DIP)
gateway: 10.0.0.254
Host RS1
eno16777736 10.0.0.101/8 (RIP1)
gateway: 10.0.0.254
Host RS2
eno16777736 10.0.0.102/8 (RIP2)
gateway: 10.0.0.254
Host DB
eno16777736 10.0.0.202/8
gateway: 10.0.0.254
时间同步：
# ntpdate cn.pool.ntp.org # hwclock --sysohc
安装软件：
HostDB
安装二进制mariadb-5.5.46
详细配置请入传送门：http://wscto.blog.51cto.com/11249394/1783131
安装NFS
# yum install -y nfs-utils
HostRS1
安装nginx，注意nginx属于epel源
# yum install-y nginx php-fpm php-mbstring php-mysql nfs-utils mariadb
HostRS2
安装nginx，注意nginx属于epel源
# yum install-y nginx php-fpm php-mbstring php-mysql nfs-utils mariadb
Host VS1
安装keepalived是为了实现高可用，nginx实现反代 nfs-utils
# yum install -y keepalived nfs-utils # wget http://nginx.org/packages/centos/6/x86_64/RPMS/nginx-1.8.1-1.el6.ngx.x86_64.rpm # rpm -ivh nginx-1.8.1-1.el6.ngx.x86_64.rpm
注意：CentOS 6中nginx版本，比较低，所以可以这样下载，在7中无需考虑
Host VS2
安装keepalived是为了实现高可用，nginx实现反代 nfs-utils
# yum install -y keepalived nfs-utils # wget http://nginx.org/packages/centos/6/x86_64/RPMS/nginx-1.8.1-1.el6.ngx.x86_64.rpm # rpm -ivh nginx-1.8.1-1.el6.ngx.x86_64.rpm
HostDB
完成安全初始化后，创建discuz数据库和discuz用户，并授权其可以远程操作数据库
# mysql_secure_installation # mysql -u root -p Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 3 Server version: 5.5.46-MariaDB-log MariaDB Server Copyright (c) 2000, 2015, Oracle, MariaDB Corporation Ab and others. Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement. MariaDB [(none)]> create database discuz; Query OK, 1 row affected (0.00 sec) MariaDB [(none)]> create user ‘discuz‘@‘localhost‘ identified by ‘magedu‘; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> grant all privileges on discuz.* to ‘discuz‘@‘%‘ identified by ‘magedu‘; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> flush privileges; Query OK, 0 rows affected (0.00 sec)
配置NFS
# mkdir /nfshare/ # ls -dl /nfshare/ drwxr-xr-x 2 root root 6 May 9 17:01 /nfshare/ # echo "/nfshare/ 10.0.0.101(rw,no_root_squash,async) 10.0.0.102(rw,no_root_squash,async)" > /etc/exports # systemctl start rpcbind <--如果是CentOS-6要使用/etc/init.d/rpcbind start Starting rpcbind: [ OK ] [[email protected] ~]# /etc/init.d/nfs start Starting NFS services: [ OK ] Starting NFS quotas: [ OK ] Starting NFS mountd: [ OK ] Starting NFS daemon: [ OK ] Starting RPC idmapd: [ OK ] # systemctl enable rpcbind <--如果是6 chkconfig rpcbind on # systemctl enable rpcbind <--如果是6 chkconfig nfs on [[email protected] ~]# chkconfig rpcbind --list rpcbind 0:off 1:off 2:on 3:on 4:on 5:on 6:off [[email protected] ~]# chkconfig nfs --list nfs 0:off 1:off 2:on 3:on 4:on 5:on 6:off [[email protected] ~]# showmount -e 127.0.0.1 Export list for 127.0.0.1: /nfshare 172.18.71.102,172.18.71.101 此步骤如果出现问题，请查看《lvs-dr负载均衡Discuz》
解压discuz的程序包至/nfsshare/目录
# mkdir /nfshare/discuz # unzip /Discuz_X3.2_SC_UTF8.zip -d /nfshare/discuz/ # ls /nfshare/discuz/ readme upload utility
Host RS1
测试链接HostDB上的mariadb
# mysql -h 10.0.0.202 -u discuz -p
挂载HostDB上的NFS共享存储目录，属主属组改为apache
# showmount -e 10.0.0.202 Export list for 10.0.0.202: /nfshare 10.0.0.102,10.0.0.101 [[email protected] ~]# mkdir /htdocs [[email protected] ~]# ls -ld /htdocs/ drwxr-xr-x 2 root root 6 May 9 17:05 /htdocs/ [[email protected] ~]# mount -t nfs 10.0.0.202:/nfshare /htdocs [[email protected] ~]# ls /htdocs/ discuz [[email protected] ~]# chown -R apache:apache /htdocs/discuz/
配置httpd，测试没有语法错误，启动httpd
# vim /etc/httpd/conf.d/vhosts.conf ... <VirtualHost *:80> ServerName admin.ws.com DocumentRoot "/htdocs/discuz/upload/" <Directory "/htdocs/discuz/upload/"> Options Indexes FollowSymLinks AllowOverride None Require all granted </Directory> </VirtualHost> # systemctl start httpd.service # ss -tnl | grep 80 LISTEN 0 128 :::80 :::*
客户端访问：http://10.0.0.102/install/
注意一定要在这里安装完成，否则搭建完反代再安装就晚了。可能会不识别静态内容
Host RS2
与Host RS1的配置相同，此处不再复制
Host VS1
挂在HostDB上的NFS共享存储到Host VS1上
# showmount -e 10.0.0.202 Export list for 10.0.0.202: /nfshare 10.0.0.0/8 # mkdir /htdocs # mount -t nfs 10.0.0.202:/nfshare /htdocs
使用upstream模块为后端RS主机做反代，并为其配置SorryServer，在后端RS主机宕机的时候，能够给用户一些友好的提示
# vim /etc/nginx/conf.d/default.conf
upstream backend {
server 10.0.0.101 weight=1 max_fails=3 fail_timeout=3;
server 10.0.0.102 weight=1 max_fails=3 fail_timeout=3;
server 10.0.0.111:8080 backup; <--当所有RS不可用时，backup可以定义一台备用主机
server 10.0.0.112:8080 backup;
}
server {
listen 80;
server_name localhost;
# 当nginx将php代码送至后端RS处理时请求头中的Host值会是backend.
# php代码在RS上处理时,其内部代码会去请求图片/层叠样式表等静态资源以填充页面.
# 而php代码去请求静态资源时使用的是如http://backend/xxxx.gif这样的url,自然是取不到的.
# 所以我们要在nginx向后代理遇到Host为backend时,将其转换为127.0.0.1.
set $my_host $http_host;
if ($http_host = "backend") {
set $my_host "127.0.0.1";
}
location / {
proxy_pass http://backend;
proxy_set_header Host $my_host;
}
}
server {
listen 8080;
server_name localhost;
charset utf-8;
root /usr/local/nginx/html;
index index.html index.htm;
# sorry_server仅提供主页面, 访问其它资源也转至主页面.
location ~ .* {
error_page 404 /;
}
}
生成sorry_server的页面，测试语法无误后启动nginx
# echo "服务维护中,请稍后访问." > /usr/share/nginx/html/index.html # nginx -t nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful [[email protected] ~]# nginx [[email protected] nginx]# ss -tnl | grep 80 LISTEN 0 128 *:8080 *:* LISTEN 0 128 *:80 *:*
修改keepalived配置文件，此处无需像lvs一样定义virtual_server和real_server
调度算法这些东西了，这些工作全由nginx完成
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected] # 邮件给本机root用户
}
notification_email_from [email protected]
smtp_server 127.0.0.1 # 使用本机作为smtp服务器
smtp_connect_timeout 30
router_id 8a028eb8 # 标识主机,可以使用主机名.
vrrp_mcast_group4 224.0.71.18 # 多播地址,用于发送心跳信号.尽量让集群内的主机处于同一个独立的多播地址.
}
# nginx进程监控脚本.如果进程不在,降低自身权重,使从节点主机优先级高于自身,将VRRP漂移至从节点主机.
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 2
weight -8
}
vrrp_instance VI_1 {
state MASTER # vrrp实例VI_1中HostA作为主
interface eth0
virtual_router_id 71 # 0-255范围内的数字,用于区分vrrp实例,所以两个实例不能一致.
priority 100 # MASTER的优先级要高一些
advert_int 1
authentication {
auth_type PASS
auth_pass uWjblY61 # 简单字符认证, 8位任意字符串.
}
virtual_ipaddress {
10.0.0.0.111/8 brd 10.0.0.111 dev eno16777736 label eno16777736:0 # VIP1
}
# 在此处调用nginx进程监控脚本
track_script {
chk_nginx
}
# 关闭争用. 争用是指当高优先级节点上线会立即争夺成为MASTER
# 而不管其它节点是否正在给用户提供服务.
#nopreempt
# 开启争用时,会延迟一段时间才开始.
#preempt_delay 300
}
vrrp_instance VI_2 {
state BACKUP # vrrp实例VI_2中HostA作为备
interface eth0
virtual_router_id 171
priority 95 # BACKUP的优先级要低一些
advert_int 1
authentication {
auth_type PASS
auth_pass uWjblY62
}
virtual_ipaddress {
10.0.0.112/8 brd 10.0.0.112 dev eno16777736 label eno16777736:1 # VIP2
}
# 在此处调用nginx进程监控脚本
track_script {
chk_nginx
}
}
启动keepalived服务，并检查ip地址和日志,可以看到HostVS1 VI_2实例的BACKUP,优先级较低，但是由于作为VI_2实例MASTER的HostVS2主机还没有启动keepalived服务，所以HostVS1获取到了VI_2实例的VIP 10.0.0.112
Host VS2
挂载HostDB上的NFS共享存储目录
# showmount -e 10.0.0.202 Export list for 10.0.0.202: /nfshare 10.0.0.0/8 # mkdir /htdocs # mount -t nfs 10.0.0.202:/nfshare /htdocs
使用upstream模块为后端RS主机做反代，并为其配置SorryServer，在后端RS主机宕机的时候，能够给用户一些友好的提示
# vim /etc/nginx/conf.d/default.conf
upstream backend {
server 10.0.0.101 weight=1 max_fails=3 fail_timeout=3;
server 10.0.0.102 weight=1 max_fails=3 fail_timeout=3;
server 10.0.0.111:8080 backup;
server 10.0.0.112:8080 backup;
}
server {
listen 80;
server_name localhost;
# 当nginx将php代码送至后端RS处理时请求头中的Host值会是backend.
# php代码在RS上处理时,其内部代码会去请求图片/层叠样式表等静态资源以填充页面.
# 而php代码去请求静态资源时使用的是如http://backend/xxxx.gif这样的url,自然是取不到的.
# 所以我们要在nginx向后代理遇到Host为backend时,将其转换为127.0.0.1.
set $my_host $http_host;
if ($http_host = "backend") {
set $my_host "127.0.0.1";
}
location / {
proxy_pass http://backend;
proxy_set_header Host $my_host;
}
}
server {
listen 8080;
server_name localhost;
charset utf-8;
root /usr/local/nginx/html;
index index.html index.htm;
# sorry_server仅提供主页面, 访问其它资源也转至主页面.
location ~ .* {
error_page 404 /;
}
}
生成sorry_server的页面，测试语法无误后启动nginx
# echo "服务维护中,请稍后访问." > /usr/share/nginx/html/index.html # nginx -t nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful [[email protected] ~]# nginx [[email protected] nginx]# ss -tnl | grep 80 LISTEN 0 128 *:8080 *:* LISTEN 0 128 *:80
修改Host VS2的keepalived配置文件，配置文件无需大改，只需要修改二者的主从关系和优先级即可
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected] # 邮件给本机root用户
}
notification_email_from [email protected]
smtp_server 127.0.0.1 # 使用本机作为smtp服务器
smtp_connect_timeout 30
router_id 8a028eb8 # 标识主机,可以使用主机名.
vrrp_mcast_group4 224.0.71.18 # 多播地址,用于发送心跳信号.尽量让集群内的主机处于同一个独立的多播地址.
}
# nginx进程监控脚本.如果进程不在,降低自身权重,使从节点主机优先级高于自身,将VRRP漂移至从节点主机.
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 2
weight -8
}
vrrp_instance VI_1 {
state BACKUP # vrrp实例VI_1中HostA作为主
interface eno16777736
virtual_router_id 71 # 0-255范围内的数字,用于区分vrrp实例,所以两个实例不能一致.
priority 98 # MASTER的优先级要低一些
advert_int 1
authentication {
auth_type PASS
auth_pass uWjblY61 # 简单字符认证, 8位任意字符串.
}
virtual_ipaddress {
10.0.0.0.111/8 brd 10.0.0.111 dev eno16777736 label eno16777736:0 # VIP1
}
# 在此处调用nginx进程监控脚本
track_script {
chk_nginx
}
# 关闭争用. 争用是指当高优先级节点上线会立即争夺成为MASTER
# 而不管其它节点是否正在给用户提供服务.
#nopreempt
# 开启争用时,会延迟一段时间才开始.
#preempt_delay 300
}
vrrp_instance VI_2 {
state BACKUP # vrrp实例VI_2中HostA作为备
interface eno16777736
virtual_router_id 171
priority 100 # BACKUP的优先级要高一些
advert_int 1
authentication {
auth_type PASS
auth_pass uWjblY62
}
virtual_ipaddress {
10.0.0.112/8 brd 10.0.0.112 dev eno16777736 label eno16777736:1 # VIP2
}
# 在此处调用nginx进程监控脚本
track_script {
chk_nginx
}
}
启动keepalived服务，并检查IP地址和日志，可以看到HostVS2作为VI_2实例的MASTER,优先级较高，在争用模式下，HostVS2立刻获取到了VI_2的VIP 10.0.0.112
测试：分别访问http://10.0.0.111/和10.0.0.112/
轮流关闭Host VS1和Host VS2的keepalived服务和nginx服务，都不会影响用户访问
由于nginx对后端RS主机的健康状态检测模块health_check已经被商业化，我们只能考虑使用由淘宝技术团队开发的tengine，所以我们要想实现，某一台RS宕机之后，仍然能继续工作，以及RS全部宕机还能够提供Sorry-server页面就需要使用tengine，我们下一篇博客细细讲解
时间： 2024-08-25 15:01:58