keepalived

 防火墙 selinux 先都确保是关闭的

# tar xf keepalived-2.0.17.tar.gz

# cd keepalived-2.0.17

# ./configure --prefix=/usr/local/keepalived

# make && make install

# mkdir /etc/keepalived

# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

主配置文件

! Configuration File for keepalived
global_defs {
router_id LVS_DEVEL
}
vrrp_script check_run {
script "/mysql_check.sh"
interval 2
fail 3
}
vrrp_sync_group VG1 {
group {
VI_1
}
}
vrrp_instance VI_1 {
state BACKUP
nopreempt                            # 设置为不抢占
interface ens33                     # ens33以实际为准
virtual_router_id 51
priority 100                         # 优先级高者为主
unicast_src_ip 192.168.1.14       # 配置单播的源地址
unicast_peer {
192.168.1.15                     # 配置单播的目标地址
｝
advert_int 1
authentication {
auth_type PASS
auth_pass 1418
}
track_script {
check_run
}
virtual_ipaddress {
192.168.1.16                            # VIP
}
}

从配置文件

! Configuration File for keepalived
global_defs {
    router_id LVS_DEVEL
}
vrrp_script check_run {
    script "/mysql_check.sh"
    interval 2
    fail 3
}
vrrp_sync_group VG1 {
    group {
        VI_1
    }
}
vrrp_instance VI_1 {
state BACKUP
nopreempt                            # 设置为不抢占
    interface ens33                     # ens33以实际为准
    virtual_router_id 51
priority 90                          # 优先级低者为从
unicast_src_ip 192.168.1.15       # 配置单播的源地址
unicast_peer {
    192.168.1.14                     #配置单播的目标地址
｝
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1418
    }
    track_script {
        check_run
    }
    virtual_ipaddress {
        192.168.1.16                            # VIP
    }
}

mysql检查脚本 

#!/bin/bash
count=$(ps -C mysqld --no-heading |wc -l)
if [ "${count}" = "0" ]; then
        #尝试启动一次mysqld，停止3秒后再次检测
        systemctl restart mysqld
        #/etc/init.d/mysqld restart
        sleep 3
        count=$(ps -C mysqld --no-heading |wc -l)
        if [ "${count}" = "0" ]; then
                #如果启动没成功，就停止keepalived触发主备切换
                systemctl stop keepalived
        fi
fi

nginx检查脚本

#!/bin/bash
count=$(ps -C nginx --no-heading |wc -l)
if [ "${count}" = "0" ]; then
        systemctl restart nginx
        #/etc/init.d/nginx restart
        sleep 3
        count=$(ps -C nginx --no-heading |wc -l)
        if [ "${count}" = "0" ]; then
                systemctl stop keepalived
        fi
fi