nginx+keepalived实现主从高可用

设备：

主：192.168.200.122

从：192.168.200.124

安装：两台都分别安装nginx以及keepalived

两台机步骤一致一主一从

安装nginx的依赖包

[root@localhost ~]#yum install gcc gcc-c++ make pcre-devel zlib-devel -y

[root@localhost ~]#useradd -M -s /sbin/nologin nginx

[root@localhost ~]#tail -l /etc/passwd;tail -l /etc/group

[root@localhost ~]#rz                                 #导入nginx源码包                             

[root@localhost ~]# ls
anaconda-ks.cfg    nginx-1.15.9.tar.gz     original-ks.cfg     模板    图片    下载     桌面
initial-setup-ks.cfg             公共                   视频      文档       音乐

[root@localhost ~]# tar xf nginx-1.15.9.tar.gz -C /usr/src

[root@localhost ~]# cd /usr/src/nginx-1.15.9

[root@localhost ~]# ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-http_stub_status_module && make && make install

[root@localhost ~]# ls /usr/local/sbin

做软连接方便查找nginx位置

[root@localhost ~]# ln -s /usr/local/bin/nginx /usr/local/sbin

[root@localhost ~]# ll /usr/local/sbin

lrwxrwxrwx. 1 root root 27 10月 21 10:50 /usr/local/sbin/nginx -> /usr/local/nginx/sbin/nginx

[root@localhost ~]# cd /usr/local/nginx/conf

[root@localhost conf]# vim nginx.conf

user  nginx nginx;
worker_processes  2;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
error_log  logs/error.log  info;

pid        logs/nginx.pid;


events {
    use epoll;
    worker_connections  10240;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    server {
        listen       80;
        server_name  localhost;

       charset utf-8;

        access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

    }


}

[root@localhost conf]#cd ../

[root@localhost nginx]#cd html

<p><em>Thank you for using nginx 192.168.200.122</em></p>                #从写192.168.200.124

[root@localhost conf]#nginx -t

[root@localhost conf]#nginx

[root@localhost conf]#killall -HUP nginx

安装keepalived

[root@localhost ~]#yum install keepalived -y

编写nginx脚本用以承载keepalived的依赖

[root@localhost ~]# vim nginx.sh

#!/bin/bash

counter=$(ps -C nginx --no-heading | wc -l)
if [ '${counter}' = '0' ];then
/usr/local/nginx/sbin/nginx
sleep 2
counter=$(ps -C nginx --no-heading | wc -l)
if [ '${counter}' = '0' ];then
systemctl stop keepalived
fi
fi

[root@localhost ~]#cd /etc/keepalived

[root@localhost ~]#cp keepalived.conf keepalived.conf.bak

[root@localhost ~]#vim keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
   route_id 192.168.200.122                 #主写122、从写124
}
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script chk_http_port {
script '/root/nginx.sh'              #启用nginx.sh脚本
insterval 2
weight -5
fall 2
rise 1
}

vrrp_instance VI_1 {
    state MASTER                    #主写MASTER、从写SLAVE
    interface ens33
    virtual_router_id 51
    priority 100                    #主写100、从写99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

    track_script {
   check_nginx
}

    virtual_ipaddress {
        192.168.200.254
    }
}

[root@localhost ~]#service keepalived start

关闭防火墙

[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# iptables -F
[root@localhost ~]# setenforce 0

[root@localhost ~]#ip a

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:f8:6e:73 brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.122/24 brd 192.168.200.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.200.254/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fef8:6e73/64 scope link 
       valid_lft forever preferred_lft forever

测试1：

条件一：当两台机的nginx、keepalived都开启时

主：192.168.200.122

[root@locahost ~]#ip a

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:3e:05:0e brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.122/24 brd 192.168.200.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.200.254/32 scope global ens33
       valid_lft forever preferred_lft forever

从：192.168.200.124

[root@locathost ~]#ip a

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:f8:6e:73 brd ff:ff:ff:ff:ff:ff
inet 192.168.200.122/24 brd 192.168.200.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fef8:6e73/64 scope link
valid_lft forever preferred_lft forever

测试2：

条件1：当关闭主的keepalived以及nginx服务时，IP192.168.200.254会不会漂移到从机上

先关闭keepalived再关闭nginx服务

[root@localhost ~]# service keepalived stop

[root@localhost ~]# nginx -s quit

主：192.168.200.122

[root@locahost ~]#ip a

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:3e:05:0e brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.122/24 brd 192.168.200.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever

从：192.168.200.124

[root@locathost ~]#ip a

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:3e:05:0e brd ff:ff:ff:ff:ff:ff
inet 192.168.200.124/24 brd 192.168.200.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet 192.168.200.254/32 scope global ens33
valid_lft forever preferred_lft forever