【中间件篇】keepalived安装和使用

1. 安装

yum install -y keepalived

2. 配置

/etc/keepalived/keepalived.conf

3. 配置示例

# ha1执行
! Configuration File for keepalived

global_defs {
   router_id LVS_DEVEL1
}

vrrp_instance k8s {
    state MASTER
    interface ens33
    nopreempt
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        11.0.1.39
    }
}

# ha2执行
cat >/etc/keepalived/keepalived.conf<<"EOF"
! Configuration File for keepalived

global_defs {
   router_id LVS_DEVEL2
}

vrrp_instance k8s {
    state BACKUP
    interface ens33
    nopreempt
    virtual_router_id 51
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        11.0.1.39
    }
}
EOF

这种情况只能实现本身keepalived的高可用检查，不能对haproxy进行高可用检查。

4. 启动

# 启动
systemctl start keepalived
# 查看状态
systemctl status keepalived
# 重启
systemctl restart keepalived
# 开机启动
systemctl enable keepalived

5. 对haproxy的高可用

haproxy参考下列文章：

【中间件篇】haproxy的安装和使用

# ha1执行
cat >/etc/keepalived/keepalived.conf<<"EOF"
! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL1
script_user root
   enable_script_security
}
vrrp_script chk_apiserver {
   script "/etc/keepalived/check_apiserver.sh"
   interval 5
   weight -5
   fall 2 
rise 1
}
vrrp_instance VI_1 {
   state MASTER
   interface ens33
   nopreempt
   virtual_router_id 51
   priority 100
   advert_int 2
   authentication {
       auth_type PASS
       auth_pass K8SHA_KA_AUTH
   }
   virtual_ipaddress {
       11.0.1.39
   }
   track_script {
      chk_apiserver
   }
}
EOF

# ha2执行
cat >/etc/keepalived/keepalived.conf<<"EOF"
! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL2
script_user root
   enable_script_security
}
vrrp_script chk_apiserver {
   script "/etc/keepalived/check_apiserver.sh"
   interval 5
   weight -5
   fall 2 
rise 1
}
vrrp_instance VI_1 {
   state BACKUP
   interface ens33
   nopreempt
   virtual_router_id 51
   priority 50
   advert_int 2
   authentication {
       auth_type PASS
       auth_pass K8SHA_KA_AUTH
   }
   virtual_ipaddress {
       11.0.1.39
   }
   track_script {
      chk_apiserver
   }
}
EOF

说明：11.0.1.39是虚拟ip。

# ha1和ha2都执行
# 健康检查脚本
cat > /etc/keepalived/check_apiserver.sh <<"EOF"
#!/bin/bash
err=0
for k in $(seq 1 3)
do
   check_code=$(pgrep haproxy)
   if [[ $check_code == "" ]]; then
       err=$(expr $err + 1)
       sleep 1
       continue
   else
       err=0
       break
   fi
done

if [[ $err != "0" ]]; then
   echo "systemctl stop keepalived"
   /usr/bin/systemctl stop keepalived
   exit 1
else
   exit 0
fi
EOF

# 添加权限
chmod +x /etc/keepalived/check_apiserver.sh

说明：这种配置无论haproxy还是keepalived本身的异常都能实现ip的飘逸，并且开启了抢占模式，MASTER正常后都有MASTER节点提供服务。