Keepalived实现Nginx负载均衡机高可用

Keepalived实现Nginx负载均衡机高可用

环境说明：

系统信息	主机名	IP
RHEL 8	master	192.168.100.1
RHEL 8	slave	192.168.100.2
RHEL 8	client	192.168.100.3

本次高可用虚拟IP（VIP）地址暂定为 192.168.100.200

Keepalived安装

配置主keepalived

#master
//关闭防火墙
[root@master ~]# systemctl disable --now firewalld
[root@master ~]# sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
[root@master ~]# setenforce 0

//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                               //配置目录
/etc/keepalived/keepalived.conf               //此为主配置文件
/etc/sysconfig/keepalived
/usr/bin/genhash
/usr/lib/.build-id
/usr/lib/.build-id/6c
/usr/lib/systemd/system/keepalived.service    //此为服务控制文件
/usr/libexec/keepalived
/usr/sbin/keepalived
······

用同样的方法在备服务器上安装keepalived

#slave
//关闭防火墙
[root@slave ~]# systemctl disable --now firewalld
[root@slave ~]# sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
[root@slave ~]# setenforce 0

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

在主备机上分别安装Nginx

在master上安装nginx

#master
[root@master ~]# yum -y install nginx
[root@master ~]# cd /usr/share/nginx/html/
[root@master html]# echo 'master' > index.html
[root@master html]# systemctl enable --now nginx
[root@master html]# ss -antl
State     Recv-Q     Send-Q         Local Address:Port         Peer Address:Port    
LISTEN    0          128                  0.0.0.0:80                0.0.0.0:*       
LISTEN    0          128                  0.0.0.0:22                0.0.0.0:*       
LISTEN    0          128                     [::]:80                   [::]:*       
LISTEN    0          128                     [::]:22                   [::]:* 

在slave上安装nginx

#slave
[root@slave ~]# yum -y install nginx
[root@slave ~]# cd /usr/share/nginx/html/
[root@slave html]# echo 'slave' > index.html
[root@slave html]# systemctl enable --now nginx
[root@slave html]# ss -antl
State     Recv-Q     Send-Q         Local Address:Port         Peer Address:Port    
LISTEN    0          128                  0.0.0.0:80                0.0.0.0:*       
LISTEN    0          128                  0.0.0.0:22                0.0.0.0:*       
LISTEN    0          128                     [::]:80                   [::]:*       
LISTEN    0          128                     [::]:22                   [::]:*  

在浏览器上访问试试，确保master上的nginx服务能够正常访问

Keepalived配置

配置主Keepalived

#master
//查看自己网卡名称，我这里是ens160
[root@master ~]# ip a
······
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.1/24 brd 192.168.100.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fef9:ec35/64 scope link 
       valid_lft forever preferred_lft forever

[root@master ~]# cd /etc/keepalived/
[root@master keepalived]# ls
keepalived.conf
[root@master keepalived]# mv keepalived.conf{,.bak}
[root@master keepalived]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface ens160                   //这里是修改成本机的网卡名称
    virtual_router_id 51
    priority 100 
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass baozi
    }
    virtual_ipaddress {
        192.168.100.200
    }
}

virtual_server 192.168.100.200 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.1 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.2 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@master ~]# systemctl enable --now keepalived

配置备Keepalived

#slave
//查看自己网卡名称，我这里是ens160
[root@slave ~]# ip a
······
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:56:9e:92 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.2/24 brd 192.168.100.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe56:9e92/64 scope link 
       valid_lft forever preferred_lft forever

[root@slave ~]# cd /etc/keepalived/
[root@slave keepalived]# ls
keepalived.conf
[root@slave keepalived]# mv keepalived.conf{,.bak}
[root@slave keepalived]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens160
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass baozi
    }
    virtual_ipaddress {
        192.168.100.200
    }
}

virtual_server 192.168.100.200 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.1 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.2 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@slave ~]# systemctl enable --now keepalived

查看VIP在哪里

在MASTER上查看

#master
[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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.1/24 brd 192.168.100.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet 192.168.100.200/32 scope global ens160        //可以看到此处有VIP
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fef9:ec35/64 scope link 
       valid_lft forever preferred_lft forever

在SLAVE上查看

#slave
[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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:56:9e:92 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.2/24 brd 192.168.100.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe56:9e92/64 scope link 
       valid_lft forever preferred_lft forever

修改内核参数，开启监听VIP功能

此步可做可不做，该功能可用于仅监听VIP的时候

在master上修改内核参数

#master
[root@master ~]# echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf
[root@master ~]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1
[root@master ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind
1

在slave上修改内核参数

#slave
[root@slave ~]# echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf
[root@slave ~]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1
[root@slave ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind
1

让Keepalived监控Nginx负载均衡机

keepalived通过脚本来监控nginx负载均衡机的状态

在master上编写脚本

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

[root@master ~]# vim /scripts/notify.sh
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" qinghao_yu@163.com
}
case "$1" in
  master)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -lt 1 ];then
            systemctl start nginx
        fi
        sendmail
  ;;
  backup)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -gt 0 ];then
            systemctl stop nginx
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac

[root@master ~]# chmod +x /scripts/check_n.sh
[root@master ~]# chmod +x /scripts/notify.sh
[root@master ~]# ll /scripts/
total 8
-rwxr-xr-x. 1 root root 142 May 20 17:34 check_n.sh
-rwxr-xr-x. 1 root root 663 May 20 17:35 notify.sh

在slave上编写脚本

#slave
[root@slave ~]# mkdir /scripts
[root@slave ~]# vim /scripts/check_n.sh
#!/bin/bash
nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
if [ $nginx_status -lt 1 ];then
    systemctl stop keepalived
fi

[root@slave ~]# vim /scripts/notify.sh
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" qinghao_yu@163.com
}
case "$1" in
  master)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -lt 1 ];then
            systemctl start nginx
        fi
        sendmail
  ;;
  backup)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -gt 0 ];then
            systemctl stop nginx
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac

[root@master ~]# chmod +x /scripts/check_n.sh
[root@master ~]# chmod +x /scripts/notify.sh
[root@slave ~]# ll /scripts/
total 8
-rwxr-xr-x. 1 root root 142 May 20 17:39 check_n.sh
-rwxr-xr-x. 1 root root 663 May 20 17:38 notify.sh

此处的脚本名称应避免与服务名相同，推荐用服务名的首字母代替，如check_n，不要给脚本起名check_nginx

配置Keepalived加入监控脚本的配置

配置主Keepalived

[root@master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_script nginx_check {
    script "/scripts/check_n.sh"
    interval 10
    weight -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens160
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass baozi
    }
    virtual_ipaddress {
        192.168.100.200
    }
    track_script {
        nginx_check
    }
    notify_master "/scripts/notify.sh master 192.168.100.200"
    notify_backup "/scripts/notify.sh backup 192.168.100.200"
}

virtual_server 192.168.100.200 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.1 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.2 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@master ~]# systemctl restart keepalived

配置备Keepalived

backup无需检测nginx是否正常，当升级为MASTER时启动nginx，当降级为BACKUP时关闭

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

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens160
    virtual_router_id 51
    priority 90
    nopreempt
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass baozi
    }
    virtual_ipaddress {
        192.168.100.200
    }
    notify_master "/scripts/notify.sh master 192.168.100.200"
    notify_backup "/scripts/notify.sh backup 192.168.100.200"
}

virtual_server 192.168.100.200 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.1 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.100.2 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@slave ~]# systemctl restart keepalived

测试验证

模拟master挂掉，slave继承

#master
//开启keepalived和nginx
[root@master ~]# systemctl start keepalived
[root@master ~]# systemctl start nginx
[root@master ~]# ss -antl
State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port    
LISTEN    0         128                0.0.0.0:80               0.0.0.0:*       
LISTEN    0         128                0.0.0.0:22               0.0.0.0:*       
LISTEN    0         128                   [::]:80                  [::]:*       
LISTEN    0         128                   [::]:22                  [::]:*   

#slave
//开启keepalived
[root@slave ~]# systemctl start keepalived
[root@slave ~]# ss -antl
State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port    
LISTEN    0         128                0.0.0.0:22               0.0.0.0:*       
LISTEN    0         128                   [::]:22                  [::]:*  

#client
//此时客户端正常访问VIP到master
[root@client ~]# curl 192.168.100.200
master

#master
//模拟master挂掉
[root@master ~]# systemctl stop nginx
[root@master ~]# ss -antl
State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port    
LISTEN    0         128                0.0.0.0:22               0.0.0.0:*       
LISTEN    0         128                   [::]:22                  [::]:* 

#client
//此时再访问VIP会访问到slave
[root@client ~]# curl 192.168.100.200
slave

#slave
//此时的slave会因为master挂掉，自动上位，启动nginx
[root@slave ~]# ss -antl
State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port    
LISTEN    0         128                0.0.0.0:80               0.0.0.0:*       
LISTEN    0         128                0.0.0.0:22               0.0.0.0:*       
LISTEN    0         128                   [::]:80                  [::]:*       
LISTEN    0         128                   [::]:22                  [::]:*  

模拟master抢救回来后重新上位

#master
//先重启启动master的nginx，再启动keepalived
[root@master ~]# systemctl start nginx
[root@master ~]# systemctl start keepalived
[root@master ~]# ss -antl
State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port    
LISTEN    0         128                0.0.0.0:80               0.0.0.0:*       
LISTEN    0         128                0.0.0.0:22               0.0.0.0:*       
LISTEN    0         128                   [::]:80                  [::]:*       
LISTEN    0         128                   [::]:22                  [::]:*  

#client
//等待一会，再访问VIP会重新访问到master
[root@client ~]# curl 192.168.100.200
master

#slave
//此时slave会让位把nginx停止
[root@slave ~]# ss -antl
State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port    
LISTEN    0         128                0.0.0.0:22               0.0.0.0:*       
LISTEN    0         128                   [::]:22                  [::]:*