keepalived集群配置+Nginx应用

前言

nginx可以在应用层面做到负载均衡，但如果nginx主机挂掉，则整个服务就会down了，因此有必要通过服务器层面的负载保障服务正常运行，这里我们应用keepalived 来实现这个功能。

拓扑结构图：

1、keepalived安装

#yum -y install keepalived

配置文件目录 /etc/keepalived/keepalived.conf

2、配置文件
192.168.3.105
[root@centos7-2 keepalived]#vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.3.249
    }
}

192.168.3.202配置文件
[root@cent7 ~]# vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.3.249
    }
}

3、分别启动keepalived服务

#service keepalived start

ping一下 192.168.3.249 是否正常

访问192.168.3.249，现在是在MASTER 192.168.3.202 的nginx页面

我们来测试下MASTER(192.168.3.202)挂掉的情况下,是否会切换到BACKUP(192.168.3.105)的nginx上去

192.168.3.202上停止keepalived服务
#service keepalived stop

192.168.3.105查看keepalived状态,已切换到MASTER状态

#[root@centos7-2 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 Mon 2019-12-09 10:09:04 CST; 5min ago
  Process: 53480 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 53481 (keepalived)
    Tasks: 3
   CGroup: /system.slice/keepalived.service
           ├─53481 /usr/sbin/keepalived -D
           ├─53482 /usr/sbin/keepalived -D
           └─53483 /usr/sbin/keepalived -D

Dec 09 10:09:13 centos7-2 Keepalived_vrrp[53483]: VRRP_Instance(VI_1) removing protocol VIPs.
Dec 09 10:14:21 centos7-2 Keepalived_vrrp[53483]: VRRP_Instance(VI_1) Transition to MASTER STATE
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: VRRP_Instance(VI_1) Entering MASTER STATE
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: VRRP_Instance(VI_1) setting protocol VIPs.
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on ens33 for 192.168.3.249
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:14:22 centos7-2 Keepalived_vrrp[53483]: Sending gratuitous ARP on ens33 for 192.168.3.249

访问页面如下，OK ！ 说明已经切换成功！！

MASTER(192.168.3.202) 再次启动keepalived服务,又返回MASTER状态

[root@cent7 ~]# service keepalived restart
Redirecting to /bin/systemctl restart keepalived.service 
[root@cent7 ~]# 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 Mon 2019-12-09 10:18:35 CST; 5s ago
  Process: 53078 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 53080 (keepalived)
    Tasks: 3
   CGroup: /system.slice/keepalived.service
           ├─53080 /usr/sbin/keepalived -D
           ├─53081 /usr/sbin/keepalived -D
           └─53082 /usr/sbin/keepalived -D

Dec 09 10:18:35 cent7 Keepalived_vrrp[53082]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Dec 09 10:18:36 cent7 Keepalived_vrrp[53082]: VRRP_Instance(VI_1) Transition to MASTER STATE
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: VRRP_Instance(VI_1) Entering MASTER STATE
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: VRRP_Instance(VI_1) setting protocol VIPs.
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on ens33 for 192.168.3.249
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: Sending gratuitous ARP on ens33 for 192.168.3.249
Dec 09 10:18:37 cent7 Keepalived_vrrp[53082]: Sending gratuitous ARP on ens33 for 192.168.3.249

再次访问页面如下:

配置keepalived日志

1、修改配置文件
vi /etc/sysconfig/keepalived

配置信息

KEEPALIVED_OPTIONS=”-D -d -S 0”

2、修改日志配置文件

#vi /etc/rsyslog.conf

末尾增加

local0.*  /var/log/keepalived.log

3、重启rsyslog服务
#service rsyslog restart
重启keepalived
#service keepalived restart

4、查看日志信息
#tail -20 /var/log/keepalived.log

2019.12.10 SHENZHEN.NanShan CY Building…