[系统运维]keepalived高可用

keepalived部署httpd

主服务器配置
关闭防火墙下载keepalived

//关闭防火墙和selinux
[root@master ~]# systemctl disable --now firewalld.service 
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@master ~]# setenforce 0
[root@master ~]# vim /etc/selinux/config 
SELINUX=disabled

//安装keepalived
[root@master ~]# yum -y install keepalived

//查看安装生成的文件
[root@master ~]# rpm -ql keepalived
/etc/keepalived
/etc/keepalived/keepalived.conf    //配置文件
/etc/sysconfig/keepalived
/usr/bin/genhash
/usr/lib/systemd/system/keepalived.service   //服务控制文件
/usr/libexec/keepalived
/usr/sbin/keepalived
......

备服务器配置
关闭防火墙和selinux、下载keepalived

//关闭防火墙和selinux
[root@slave ~]# systemctl disable --now firewalld.service 
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@slaver ~]# setenforce 0
[root@slave ~]# vim /etc/selinux/config 
SELINUX=disabled

//安装keepalived
[root@slaver ~]# yum -y install keepalived

在主备机上分别安装httpd
主服务器

[root@master ~]# yum -y install httpd
[root@master ~]# cd /var/www/html/
[root@master html]# ls
[root@master html]# echo "master" > index.html
[root@master html]# cat index.html 
master


//启动httpd服务
[root@master html]# systemctl start httpd.service 
[root@master html]# ss -antl
State       Recv-Q Send-Q Local Address:Port               Peer Address:Port              
LISTEN      0      128     *:22                  *:*                  
LISTEN      0      100    127.0.0.1:25                  *:*                  
LISTEN      0      128    :::80                 :::*                  
LISTEN      0      128    :::22                 :::*                  
LISTEN      0      100       ::1:25                 :::*             

备服务器

[root@slave ~]# yum -y install httpd
[root@slave ~]# cd /var/www/html/
[root@slave html]# ls
[root@slave html]# echo "slave" > index.html
[root@slave html]# cat index.html 
slave

//启动httpd服务
[root@slave html]# systemctl start httpd.service
[root@slave html]# ss -antl
State  Recv-Q Send-Q  Local Address:Port   Peer Address:Port Process 
LISTEN 0      128           0.0.0.0:22          0.0.0.0:*            
LISTEN 0      128                 *:80                *:*            
LISTEN 0      128              [::]:22             [::]:*            

keepalived配置
主服务器配置

[root@master ~]# cd /etc/keepalived/
[root@master keepalived]# ls
keepalived.conf
[root@master keepalived]# cp keepalived.conf{,-bak}   //本分原配置文件
[root@master keepalived]# ls
keepalived.conf  keepalived.conf-bak
[root@master keepalived]# rm -rf keepalived.conf
[root@master keepalived]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33    //网卡名要和IP a 网卡名一样
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wjm123   //密码
    }
    virtual_ipaddress {
        192.168.164.250
    }
}

virtual_server 192.168.164.250 80 {    //VIP  加端口号
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP
    
    real_server 192.168.164.128 80 {     //主服务器IP
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.164.137 80 {   //备服务器IP
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

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

//把配置文件传到备服务器上，应为主备都需要配置
[root@master keepalived]# scp keepalived.conf root@192.168.164.137:/etc/keepalived
The authenticity of host '192.168.164.137 (192.168.164.137)' can't be established.
ECDSA key fingerprint is SHA256:LHRhfz+dzwLMs+25QRqhHneTBq5ScV3htejYRiSJ7Pk.
ECDSA key fingerprint is MD5:cc:ac:35:a9:d1:e5:74:d9:8b:11:62:1c:31:9e:01:5d.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.164.137' (ECDSA) to the list of known hosts.
root@192.168.164.137's password: 
keepalived.conf             100%  868   339.8KB/s   00:00    

配置备keepalived

//查看目录中是否有来自主服务器发来的文件
[root@slave keepalived]# ls
keepalived.conf  keepalived.conf-bak


//修改配置文件
[root@slave keepalived]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP   //修改为backup 备份
    interface ens33
    virtual_router_id 51
    priority 90    //权重改成90，这样VIP才能到128主机上
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wjm123
    }
    virtual_ipaddress {
        192.168.164.250
    }
}

virtual_server 192.168.164.250 80 {   //VIP地址 和服务端口号
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP
    
    real_server 192.168.164.128 80 {   //主服务器
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.164.137 80 {   //备服务器
        weight 1  
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

//重启并设置为开机自启
[root@slave keepalived]# systemctl start keepalived
[root@slave keepalived]# systemctl enable keepalived
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.

查看VIP在哪里
主服务查看

[root@master keepalived]# ip a
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:73:96:01 brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.128/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.164.250/32 scope global ens33      //看见此次主服务上有VIP，说明是这台主机提供的服务（面向客户端的IP地址）
       valid_lft forever preferred_lft forever
    inet6 fe80::65f2:205e:c9e8:7e94/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

备服务器查看

[root@slave ~]# ip a
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:b0:c6:8a brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.137/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::394:4b63:da73:a11/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

测试
关闭主服务器上的keepalived

[root@master ~]# systemctl stop keepalived
[root@master ~]# ip a
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:73:96:01 brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.128/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::65f2:205e:c9e8:7e94/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever


//去备服务器查看，发现vip到备服务了说明是备服务器提供的服务
[root@slave ~]# ip a
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:b0:c6:8a brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.137/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.164.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::394:4b63:da73:a11/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

关闭主服务的Keeplived，发现VIP到了备服务器，此时去访问网站是备服服务器提供的服务

让keepalived通过脚本监控httpd负载均衡机

keepalived通过脚本来监控nginx负载均衡机的状态

主服务器编辑脚本
两个脚本

[root@master ~]# mkdir /scripts
[root@master ~]# cd /scripts/
[root@master scripts]# vi check_h.sh
#!/bin/bash
httpd_status=$(ps -ef|grep -Ev "httpd|$0"|grep '\bhttpd\b'|wc -l)
if [ $httpd_status -lt 1 ];then
    systemctl stop keepalived
fi

[root@master scripts]# chmod +x check_h.sh    //添加执行的权限 X
[root@master scripts]# ll
总用量 4
-rwxr-xr-x. 1 root root 142 10月 21 21:16 check_h.sh

//创建编辑第二个脚本
[root@master scripts]# vi notify.sh
#!/bin/bash
VIP=$2
case "$1" in
  master)
        httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
        if [ $httpd_status -lt 1 ];then
            systemctl start httpd
        fi
  ;;
  backup)
        httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l)
        if [ $httpd_status -gt 0 ];then
            systemctl stop httpd
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac

[root@master scripts]# chmod +x notify.sh 
[root@master scripts]# ll
总用量 8
-rwxr-xr-x. 1 root root 142 10月 21 21:16 check_h.sh
-rwxr-xr-x. 1 root root 432 10月 21 21:26 notify.sh

//待备服务器创建完/scripts后，再把notify脚本用scp传到对面相同目录中
//待备服务器创建完/scripts后，再把notify脚本用scp传到对面相同目录中
//待备服务器创建完/scripts后，再把notify脚本用scp传到对面相同目录中
[root@master scripts]# scp notify.sh root@192.168.164.137:/scripts
root@192.168.164.137's password: 
notify.sh                   100%  432   109.0KB/s   00:00    

备服务器编辑脚本

[root@slave ~]# mkdir /scripts
[root@slave ~]# cd /scripts/

//查看是否收到对面穿过来的脚本文件
[root@slave scripts]# ll
总用量 4
-rwxr-xr-x. 1 root root 432 10月 21 21:30 notify.sh

配置keepalived加入监控脚本的配置

配置主服务器的keepalived

//开启主服务器上的Keeplived
[root@master scripts]# systemctl start keepalived
[root@master scripts]# ip a
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:73:96:01 brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.128/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.164.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::65f2:205e:c9e8:7e94/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

//编辑主服务的keepalived配置文件
[root@master scripts]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_script httpd_check {       //添加以下4行
    script "/scripts/check_h.sh"
    interval 1
    weight -20
}


vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wjm123
    }
    virtual_ipaddress {
        192.168.164.250
    }
    track_script {
           httpd_check
    }
    notify_master "/scripts/notify.sh master 192.168.164.250"    //添加以下两行
    notify_backup "/scripts/notify.sh backup 192.168.164.250"
}

virtual_server 192.168.164.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.164.128 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.164.137 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

//重启服务
[root@master scripts]# systemctl restart keepalived
           

备服务器配置keepalived

[root@slave scripts]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wjm123
    }
    virtual_ipaddress {
        192.168.164.250
    }
    notify_master "/scripts/notify.sh master 192.168.164.250"    //添加以下两行内容
    notify_backup "/scripts/notify.sh backup 192.168.164.250"
}

virtual_server 192.168.164.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.164.128 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.164.137 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

//重启服务
[root@slave ~]# systemctl restart keepalived

验证

//模拟关闭主上面的httpd，发现keepalived服务已经自动关闭了
[root@master scripts]# systemctl stop httpd
[root@master scripts]# ss  -antl
State      Recv-Q Send-Q Local Address:Port               Peer Address:Port              
LISTEN     0      128     *:22                  *:*                  
LISTEN     0      100    127.0.0.1:25                  *:*                  
LISTEN     0      128    :::22                 :::*                  
LISTEN     0      100       ::1:25                 :::*                  
[root@master scripts]# ip a     //此时去查看IP发现VIP已经不在了
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:73:96:01 brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.128/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::65f2:205e:c9e8:7e94/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@master scripts]# systemctl status keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: inactive (dead) since 四 2021-10-21 23:41:22 CST; 55s ago
  Process: 117289 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 117290 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/keepalived.service

10月 21 23:41:21 master Keepalived_vrrp[117292]: WARNING -...
10月 21 23:41:21 master Keepalived_vrrp[117292]: SECURITY ...
10月 21 23:41:21 master Keepalived_vrrp[117292]: VRRP_Inst...
10月 21 23:41:21 master Keepalived_vrrp[117292]: Using Lin...
10月 21 23:41:21 master Keepalived_vrrp[117292]: VRRP sock...
10月 21 23:41:21 master Keepalived[117290]: Stopping
10月 21 23:41:21 master systemd[1]: Stopping LVS and VRRP ...
10月 21 23:41:21 master Keepalived_healthcheckers[117291]: ...
10月 21 23:41:21 master Keepalived_healthcheckers[117291]: ...
10月 21 23:41:22 master systemd[1]: Stopped LVS and VRRP H...
Hint: Some lines were ellipsized, use -l to show in full.


//去备服务器查看IP，发现VIP在备服务上，现在访问VIP 所提供服务的是备服务器
[root@slave scripts]# ip a
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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:b0:c6:8a brd ff:ff:ff:ff:ff:ff
    inet 192.168.164.137/24 brd 192.168.164.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.164.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::394:4b63:da73:a11/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

[root@slave scripts]# ss -antl
State  Recv-Q Send-Q   Local Address:Port   Peer Address:Port 
Process                                                       
LISTEN 0      128            0.0.0.0:22          0.0.0.0:*    
                                                              
LISTEN 0      128                  *:80                *:*    
                                                              
LISTEN 0      128               [::]:22             [::]:*    

现在去访问，查看是否是备提供的服务