部署 Keepalived 及配置 VIP

1 准备工作¶

1.1 服务器准备¶

此处在 MySQL 集群节点上进行 Keepalived 的安装，一起实现负载均衡和 MySQL 的高可用，节点规划如下：

Keepalived-1 节点，IP 为 10.1.11.187
Keepalived-2 节点，IP 为 10.1.11.189

其他信息：

VIP：10.1.11.137

1.2 软件准备¶

可以在 Keepalived 官网下载对应的安装包，此处下载的是 keepalived-2.2.7.tar.gz。

wget --no-check-certificate https://www.keepalived.org/software/keepalived-2.2.7.tar.gz

2 安装 Keepalived¶

在两个节点上分别执行以下命令安装 Keepalived：

# 安装依赖包
yum install -y gcc-c++ pcre-devel openssl-devel popt-devel gcc automake autoconf libtool make ca-certificates

tar zxvf keepalived-2.2.7.tar.gz -C /opt

cd /opt/keepalived-2.2.7

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

make && make install

3 配置系统服务¶

在两个节点上分别执行以下命令：

cp /usr/local/keepalived/etc/sysconfig/keepalived  /etc/sysconfig/keepalived
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived
cp /opt/keepalived-2.2.7/keepalived/etc/init.d/keepalived /etc/init.d/keepalived
mkdir -p /etc/keepalived

加为系统服务且开机自启动：

chkconfig --add keepalived
chkconfig keepalived on

4 编写 Keepalived 切换脚本¶

在两个节点上执行以下命令创建 Keepalived 切换脚本：

cat <<EOF >> /usr/local/keepalived/down.sh
#!/bin/bash
pkill keepalived
EOF

# 赋予切换脚本执行权限
chmod +x /usr/local/keepalived/down.sh

5 配置 Keepalived¶

5.1 配置 Keepalived-1 节点¶

将 Keepalived-1 上的 Keepalived 配置文件 /etc/keepalived/keepalived.conf 修改为以下内容：

! Configuration File for keepalived

global_defs {
   router_id DE_HA
}

vrrp_instance VI_1 {
    state MASTER
    interface ens192
    virtual_router_id 51
    priority 100
    advert_int 1
    #本机 ip
    unicast_src_ip 10.1.11.187
    unicast_peer {
        #对端 ip
        10.1.11.189
}
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.1.11.137
    }
}

virtual_server 10.1.11.137 3306 {
    delay_loop 2
    persistence_timeout 50
    protocol TCP

    real_server 10.1.11.187 3306 {
        weight 3
        notify_down /usr/local/keepalived/down.sh
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

virtual_server 10.1.11.137 80 {
    delay_loop 2
    persistence_timeout 50
    protocol TCP

    real_server 10.1.11.187 80 {
        weight 3
        notify_down /usr/local/keepalived/down.sh
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

注意：

配置文件中的 “interface ens192”，需要视具体环境设置对应的网卡，如 “eth0” 等；
注意配置文件中的 "state MASTER"、"priority 100"。

5.2 配置 Keepalived-2 节点¶

将 Keepalived-2 节点上的 Keepalived 配置文件 /etc/keepalived/keepalived.conf 修改为以下内容：

! Configuration File for keepalived

global_defs {
   router_id DE_HA
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens192
    virtual_router_id 51
    priority 50
    advert_int 1
    #本机ip
    unicast_src_ip 10.1.11.189
    unicast_peer {
        #对端ip
        10.1.11.187
    }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.1.11.137
    }
}

virtual_server 10.1.11.137 3306 {
    delay_loop 2
    persistence_timeout 50
    protocol TCP

    real_server 10.1.11.189 3306 {
        weight 3
        notify_down /usr/local/keepalived/down.sh
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

virtual_server 10.1.11.137 80 {
    delay_loop 2
    persistence_timeout 50
    protocol TCP

    real_server 10.1.11.189 80 {
        weight 3
        notify_down /usr/local/keepalived/down.sh
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

注意：

配置文件中的 “interface eth0”，需要视具体环境设置对应的网卡，如 “ens192” 等；
注意配置文件中的 "state BACKUP"、"priority 50"。

6 启动 Keepalived 服务¶

在两个节点上分别启动 Keepalived 服务：

service keepalived start

keepalived-启动

7 验证高可用配置¶

Keepalived 配置的 MASTER 节点为 Keepalived-1 节点，可以通过在两个节点上执行命令，查看配置的 VIP 在哪台机器上。

ip addr

在 Keepalived-1 节点上可以看到对应的网卡上存在两个 IP，分别是自身 IP 10.1.11.187 和 VIP 10.1.11.137。

Keepalived-1 节点-查看ip

而 Keepalived-2 节点上只会看到 IP 10.1.11.189。

Keepalived-2 节点-查看ip

当在 Keepalived-1 节点上关闭 Nginx 服务后，再次执行上述命令，可以看到 Keepalived-2 节点上存在两个 IP，VIP 已经漂移到了 Keepalived-2 节点上。

keepalived-2 节点-查看ip

部署 Keepalived 及 配置 VIP