keepAlived 集群安装通过动态IP 实现服务高可用

目标：

实现nginx 集群高可用，通过访问虚拟IP 地址完成nginx服务的请求，在 主nginx 服务器不能正常提供服务时，备份nginx服务器能自动完成服务接管。并邮件提醒管理员（此功能后续实现）

 

 

 

 

前提：

两台服务器IP 分别 为 192.168.1.137, 192.168.1.138，分别在每个服务器上部署nginx 服务，并完成集群配置。

 

 

准备：

安装 open SSL

sudo yum install openssl-devel 

 

安装过程中要交互一下 y

 

 

 

 

安装libnl/libnl-3依赖

sudo yum -y install libnl libnl-devel

 

 

 

 

 

 

安装keepalived

下载keepalived

https://www.keepalived.org/

 

 

 将下载的gz包上传到Linux 服务器

 

 

 解压到/opt/module/

 

 

 cd 到解压后的目录 执行 ./congigure

 

 

执行后是这样的就对了。。

 

 

 

sudo  make

不提示错误---ok

sudo make install

不提示错误---ok

安装成功后会生成以下两个目录；分别存放的是 执行文件和配置文件

/usr/local/sbin/keepalived

/usr/local/etc/keepalived

配置keepalived

创建目录

/etc/keepalived/ 在目录内创建 keepalived.conf

创建配置文件

配置文件内容如下：

192.168.1.138为备份BACKUP

global_defs{
    router_id lb138
}
vrrp_instance nacos{
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 50
    advert_int 1
    authentication{
        auth_type:PASS
        auth_pass:1234
    }
    virtual_ipaddress{
        192.168.1.254
    }

}

virtual_server 192.168.1.254 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.1.138 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            retry 3
            connect_port 80
            delay_before_retry 3
        }
    }
}
 

192.168.1.137 为master主机

global_defs {
    router_id lb137
}
vrrp_instance nacos {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type:PASS
        auth_pass:1234
    }
    virtual_ipaddress {
        192.168.1.254
    }

}
 virtual_server 192.168.1.254 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.1.137 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            retry 3
            connect_port 80
            delay_before_retry 3
        }
    }
}
 

对上面的配置文件需要注意：

1、router_id: #此处注意router_id为负载均衡标识  keepalived 服务器的标识，在局域网内应该是唯一的。 

2、vrrp_instance ：vrrp 的实例编码 相同的vrrp ,vrrp_instance 相同

3、state: #设置 lvs 的状态，MASTER 和 BACKUP 两种，必须大写

4、virtual_router_id:这个标识是一个数字，同一个 vrrp 实例使用相同标识

 

5、priority:优先级 值越大，优先级越高,标识为MASTER的 vrrp  要比 BACKUP 的vrrp 要大

6、virtual_ipaddress:这个IP 地址要与客户端（调用者）在同一个网络中（同一网段，或者是在防火墙或路由器配置了不同网络之间互联策略） 这里使用了同一个网段的地址

启动服务  service keepalived start

[root@machine138 keepalived]# service  keepalived start
Redirecting to /bin/systemctl start keepalived.service
[root@machine138 keepalived]# service  keepalived status
Redirecting to /bin/systemctl status keepalived.service
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
   Active: active (running) since 一 2023-02-20 13:40:51 CST; 18s ago
     Docs: man:keepalived(8)
           man:keepalived.conf(5)
           man:genhash(1)
           https://keepalived.org
  Process: 7846 ExecStart=/usr/local/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 7847 (keepalived)
    Tasks: 3
   CGroup: /system.slice/keepalived.service
           ├─7847 /usr/local/sbin/keepalived -D
           ├─7848 /usr/local/sbin/keepalived -D
           └─7849 /usr/local/sbin/keepalived -D

 

把服务注册为系统 服务，开机自启动 systemctl enable keepalived

[root@machine138 keepalived]# systemctl enable keepalived
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service.
[root@machine138 keepalived]# systemctl enable keepalived

 

 

 

 

 

 

 

 

 

 

 

把 1.137reboot

此时观察 138的IP地址及 客户端ping的情况

 

 

 虚拟IP 192.168.1.254 已经漂移到了 138服务器上

 

 

 

测试nginx

 

 

附：服务常用命令

 以下以keepalived服务为例：

systemctl start keepalived            开启服务
systemctl stop keepalived            关闭服务
systemctl status keepalived 　　　　显示状态
systemctl restart keepalived    　　　　重启服务
systemctl enable keeplived   　　　　开机启动服务
systemctl disable keeplived    　　　　禁止开机启动
systemctl list-units            　　查看系统中所有正在运行的服务
systemctl list-unit-files    　　　　查看系统中所有服务的开机启动状态
systemctl list-dependencies keepalived        　　查看系统中服务的依赖关系
systemctl mask keepalived                        冻结服务
systemctl unmask keepalived                     解冻服务
systemctl set-default multi-user.target     开机时不启动图形界面
systemctl set-default graphical.target      开机时启动图形界面
　　修改服务配置文件后需要
　　systemctl daemon-reload
 
　　设置服务开机自启动
　　systemctl enable keepalived
 
　　查询是否自启动服务
　　systemctl is-enabled keepalived
　　或
　　systemctl list-units |grep keepalived

 
　　取消服务器开机自启动
　　systemctl disable keepalived# 显示某个 Unit 是否正在运行
$ systemctl is-active keepalived# 显示某个 Unit 是否处于启动失败状态
$ systemctl is-failed keepalived# 显示某个 Unit 服务是否建立了启动链接
$ systemctl is-enabled keepalived