高可用集群搭建，避免单点故障

1. 安装

# 更新软件源中的所有软件列表
sudo apt update
#安装Keepalived
sudo apt install keepalived -y

2. 配置

2.1 Master主机配置

# 复制原本的keepalived.conf
cp /usr/share/doc/keepalived/samples/keepalived.conf.sample /etc/keepalived/keepalived.conf

#修改配置文件为：

global_defs {
   # 当前网络中唯一
   router_id lb01
}

vrrp_instance VI_1 {
    # 指定角色  当前MASTER
    state MASTER
    # 绑定网卡  需要改动到当前服务器的虚拟网卡
    interface enp0s3
    # 虚拟路由编号 主从一致
    virtual_router_id 51
    nopreempt
    # 优先级 数值越大优先级越高
    priority 100
    # 检查间隔 1秒
    advert_int 1
    virtual_ipaddress {
        # 虚拟ip (VIP)
        192.168.1.116 dev enp0s3 lable enp0s3:3
    }
}

2.2 BackUP主机配置

# 复制原本的keepalived.conf
cp /usr/share/doc/keepalived/samples/keepalived.conf.sample /etc/keepalived/keepalived.conf


#修改配置文件为：
global_defs {
   # 当前网络中唯一
   router_id lb02
}

vrrp_instance VI_1 {
    # 指定角色  当前BACKUP
    state BACKUP
    # 绑定网卡  需要改动到当前服务器的虚拟网卡
    interface enp0s3
    # 虚拟路由编号 主从一致
    virtual_router_id 51
    nopreempt
    # 优先级 从比主少50
    priority 50
    # 检查间隔 1秒
    advert_int 1
    virtual_ipaddress {
        # 虚拟ip (VIP)
        192.168.1.116 dev enp0s3 lable enp0s3:3
    }
}

3. 主从服务启动

systemctl start keepalived
# 关闭防火墙
sudo ufw disable

4. 测试

4.1 内网ping 虚拟ip

4.2 查看Master ip 配置 并关闭Master 服务器再试

root@ubuntu20-04:/etc/keepalived# ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:3a:6b:07 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.111/24 brd 192.168.1.255 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet 192.168.1.116/32 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe3a:6b07/64 scope link 
       valid_lft forever preferred_lft forever
# 发现虚拟ip 在当前Master服务器上  然后关机  
root@ubuntu20-04:/etc/keepalived# sudo shutdown now
root@ubuntu20-04:/etc/keepalived# Connection closing...Socket close.

Connection closed by foreign host.

Disconnected from remote host(192.168.1.111) at 20:24:44.

Type `help' to learn how to use Xshell prompt.

4.3 尝试 ping 192.168.1.116 虚拟ip

4.4 查看BackUP服务器 ip 配置

root@ubuntu20-04BACKUP:/etc/keepalived# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:fc:a6:28 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.112/24 brd 192.168.1.255 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet 192.168.1.116/32 scope global enp0s3
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fefc:a628/64 scope link 
       valid_lft forever preferred_lft forever

虚拟 ip 成功漂移到BackUP服务器