keepalived補充

一脂矫、keepalived基于服務器nginx掛了，不會自動切換

1.1 書寫腳本（時刻檢查nginx的狀態(tài)霉晕，如果nginx關閉庭再，keepalived也關閉）

[root@lb01 /server/scripts]# cat check-ngx.sh 
#!/bin/bash

count=`ps -ef|grep nginx|grep -v grep|wc -l`

if [ $count -eq 0 ];then 
  systemctl stop keepalived
fi

注：腳本名字不要包含監(jiān)控對象的名字

1.2 通過keepalived運行檢查nginx服務的腳本

1>給腳本check-ngx.sh 一個執(zhí)行權(quán)限

[root@lb01 ~]#  chmod +x /server/scripts/check-ngx.sh
[root@lb01 ~]# ll /server/scripts/check-ngx.sh 
-rwxr-xr-x 1 root root 116 Jun 17 09:15 /server/scripts/check-ngx.sh
[root@lb01 ~]#

1.3 配置keepalived

[root@lb01 ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
……
vrrp_script check_ngx {
   script  /server/scripts/check-ngx.sh
   interval  2
   weight  1
}

vrrp_instance VI_1 {
    ……
    track_script{
        check_ngx
    }
}
[root@lb01 ~]#

image

1.4 重啟keepalived

systemctl restart keepalived.service

1.5測試

\\lb01上
[root@lb01 ~]# ip a|grep 0.3
    inet 10.0.0.3/24 scope global secondary eth0:1
[root@lb01 ~]# systemctl stop nginx
[root@lb01 ~]# ip a|grep 0.3
[root@lb01 ~]#                                            \\\虛擬ip飄逸走了

\\lb02上
[root@lb02 ~]# ip a|grep 0.3
    inet 10.0.0.3/24 scope global secondary eth0:1

\\\回到lb01上
[root@lb01 ~]# systemctl start nginx
[root@lb01 ~]# ip a|grep 0.3
[root@lb01 ~]# systemctl start keepalived.service 
[root@lb01 ~]# ip a|grep 0.3   \\虛擬IP自動飄逸回來
    inet 10.0.0.3/24 scope global secondary eth0:1

二捞奕、keepalived雙主模式

目的：減輕負載均衡的壓力

image

2.1 keepalived雙主模式配置

image

分別重啟keepalived服務

\\\lb01
[root@lb01 /etc/keepalived]# systemctl restart keepalived.service [root@lb01 /etc/keepalived]# ip a |egrep "0.3|0.4"
    inet 10.0.0.3/24 scope global secondary eth0:1

\\\\lb02
[root@lb02 /etc/keepalived]# systemctl restart keepalived.service [root@lb02 /etc/keepalived]# ip a |egrep "0.3|0.4"

keepalived雙主模式配置

\\\\lb01的keepalived雙主配置文件
! Configuration File for keepalived

global_defs {
    router_id lb01
}
vrrp_script jiancha {
script "/server/scripts/jiancha.sh"
interval 2
weight 1
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1  
    }
    track_script {
    jiancha
    }
}
vrrp_instance VI_2 {
    state BACKUP
    interface eth0
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.4/24 dev eth0 label eth0:2
    }
}

\\\\\\\lb02的keepalived雙主配置文件
! Configuration File for keepalived

global_defs {
    router_id lb02
}

vrrp_instance VI_1 {   
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1  
    }
}
vrrp_instance VI_2 {
    state MASTER
    interface eth0
    virtual_router_id 52
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.4/24 dev eth0 label eth0:2
    }
}

讓lb01和lb02的nginx配置文件相同

vim /etc/nginx/nginx.conf  :

     upstream  web_pools {
     server 10.0.0.7:80 weight=1 max_fails=3 fail_timeout=10s;
     server 10.0.0.8:80 weight=1 max_fails=3 fail_timeout=10s;
     }
#    include /etc/nginx/conf.d/*.conf;
     server {
     listen 80;
     server_name www.oldboy.com;
     location / {
         proxy_pass http://web_pools;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $remote_addr; 
        }
     }
     server {
     listen 80;
     server_name blog.oldboy.com;
     location / {
         proxy_pass http://web_pools;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $remote_addr;
        }
     }

2.1 在命令行curl測試是否正常

\\\lb01
[root@lb01 ~]# curl 10.0.0.3
web02 www.oldboy.com
[root@lb01 ~]# curl 10.0.0.3
web01 www.oldboy.com
[root@lb01 ~]# curl 10.0.0.4
web02 www.oldboy.com
[root@lb01 ~]# curl 10.0.0.4
web01 www.oldboy.com
[root@lb01 ~]# 

\\\lb02
[root@lb02 ~]# curl 10.0.0.3
web02 www.oldboy.com
[root@lb02 ~]# curl 10.0.0.3
web01 www.oldboy.com
[root@lb02 ~]# curl 10.0.0.4
web02 www.oldboy.com
[root@lb02 ~]# curl 10.0.0.4
web01 www.oldboy.com
[root@lb02 ~]#

2.1 在瀏覽器進行測試

1>先在Windows本地hosts文件中配置解析

10.0.0.3 www.oldboy.com
10.0.0.4 blog.oldboy.com

2>瀏覽器測試

image

2.1 測試高可用是否正常

假如將其中1臺lb01關機，然后測試www.oldboy.com和blog.oldboy.com在瀏覽器是否還能正常顯示

三拄轻、每個域名綁定對應ip

3.1 修改nginx配置

image

3.2 重啟服務

重啟服務報Cannot assign requested address的錯誤
nginx無法把本地不存在的ip地址進行綁定

[root@lb01 ~]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: [emerg] bind() to 10.0.0.7:80 failed (99: Cannot assign requested address)   \\不能分配的請求ip地址
nginx: configuration file /etc/nginx/nginx.conf test failed

解決：修改內(nèi)核參數(shù)
在/etc/sysctl.conf文件中颅围，追加net.ipv4.ip_nonlocal_bind = 1
內(nèi)核生效：sysctl -p

[root@lb01 ~]# cat  /etc/sysctl.conf 
……
net.ipv4.ip_nonlocal_bind = 1
[root@lb01 ~]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1
[root@lb01 ~]#

注：執(zhí)行net.ipv4.ip_nonlocal_bind = 1，背后修改了哪里恨搓？

[root@lb01 ~]# #net.ipv4.ip_nonlocal_bind
[root@lb01 ~]# # /proc/sys/ 
[root@lb01 ~]# #net.ipv4.ip_nonlocal_bind
[root@lb01 ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind  \\修改的是這里
1

四院促、keepalived高可用故障案例

腦裂/裂腦

原因：
??1>SELinux/防火墻可以開啟
??2>高可用服務器對之間心跳線鏈路故障，導致無法正常通信
??3>高可用服務器對上心跳網(wǎng)卡地址等信息配置不正確斧抱，導致發(fā)送心跳失敗常拓。

解決：
??1>兩條心跳線路
??2>只要備任務主掛了，我讓你直接掛了
??3>書寫一個腳本辉浦，發(fā)送腦裂發(fā)送郵件