Keepalived+Nginx+Tomcat 实现高可用Web集群



keepalived如何升级版本_keepalived如何升级版本

2018.01.08 20:28* 字数 1382 阅读 965评论 1喜欢 9



 




keepalived如何升级版本_c/c++_02


集群规划图片


一、Nginx的安装过程

1.下载Nginx安装包，安装依赖环境包

(1)安装 C++编译环境
yum  -y install gcc   #C++
(2)安装pcre
yum  -y install pcre-devel
(3)安装zlib
yum  -y install  zlib-devel
(4)安装Nginx

定位到nginx 解压文件位置，执行编译安装命令

[root@localhost nginx-1.12.2]# pwd
/usr/local/nginx/nginx-1.12.2 [root@localhost nginx-1.12.2]# ./configure && make && make install 
[root@localhost nginx-1.12.2]# pwd
/usr/local/nginx/nginx-1.12.2 [root@localhost nginx-1.12.2]# ./configure && make && make install
(5)启动Nginx

安装完成后先寻找那安装完成的目录位置

[root@localhost nginx-1.12.2]# whereis nginx
nginx: /usr/local/nginx [root@localhost nginx-1.12.2]# 
[root@localhost nginx-1.12.2]# whereis nginx
nginx: /usr/local/nginx [root@localhost nginx-1.12.2]#

进入Nginx子目录sbin启动Nginx

[root@localhost sbin]# ls
nginx
[root@localhost sbin]# ./nginx &
[1] 5768 [root@localhost sbin]# 
[root@localhost sbin]# ls
nginx
[root@localhost sbin]# ./nginx &
[1] 5768 [root@localhost sbin]#

查看Nginx是否启动


 


keepalived如何升级版本_keepalived如何升级版本_03


Niginx启动成功截图


或通过进程查看Nginx启动情况

[root@localhost sbin]# ps -aux|grep nginx
root       5769  0.0 0.0 20484 608 ? Ss 14:03 0:00 nginx: master process ./nginx nobody 5770 0.0 0.0 23012 1620 ? S 14:03 0:00 nginx: worker process root 5796 0.0 0.0 112668 972 pts/0 R+ 14:07 0:00 grep --color=auto nginx [1]+ 完成 ./nginx [root@localhost sbin]# 
[root@localhost sbin]# ps -aux|grep nginx
root       5769  0.0 0.0 20484 608 ? Ss 14:03 0:00 nginx: master process ./nginx nobody 5770 0.0 0.0 23012 1620 ? S 14:03 0:00 nginx: worker process root 5796 0.0 0.0 112668 972 pts/0 R+ 14:07 0:00 grep --color=auto nginx [1]+ 完成 ./nginx [root@localhost sbin]#

到此Nginx安装完成并启动成功。

(6)Nginx快捷启动和开机启动配置

编辑Nginx快捷启动脚本【注意Nginx安装路径，需要根据自己的NGINX路径进行改动】

[root@localhost init.d]# vim /etc/rc.d/init.d/nginx

[root@localhost init.d]# vim /etc/rc.d/init.d/nginx


1 #!/bin/sh
  2 #
  3 # nginx - this script starts and stops the nginx daemon
  4 #
  5 # chkconfig: - 85 15
  6 # description: Nginx is an HTTP(S) server, HTTP(S) reverse \
  7 # proxy and IMAP/POP3 proxy server
  8 # processname: nginx
  9 # config: /etc/nginx/nginx.conf
 10 # config: /usr/local/nginx/conf/nginx.conf
 11 # pidfile: /usr/local/nginx/logs/nginx.pid
 12  
 13 # Source function library.
 14 . /etc/rc.d/init.d/functions
 15  
 16 # Source networking configuration.
 17 . /etc/sysconfig/network
 18  
 19 # Check that networking is up.
 20 [ "$NETWORKING" = "no" ] && exit 0
 21 nginx="/usr/local/nginx/sbin/nginx"
 22 prog=$(basename $nginx)
 23 NGINX_CONF_FILE="/usr/local/nginx/conf/nginx.conf"
 24 [ -f /etc/sysconfig/nginx ] && . /etc/sysconfig/nginx
 25 lockfile=/var/lock/subsys/nginx
 26  
 27 make_dirs() {
 28     # make required directories
 29     user=`$nginx -V 2>&1 | grep "configure arguments:" | sed 's/[^*]*--user=\([^ ]*\).*/\1/g' -`
 30     if [ -z "`grep $user /etc/passwd`" ]; then
 31     useradd -M -s /bin/nologin $user
 32     fi
 33     options=`$nginx -V 2>&1 | grep 'configure arguments:'`
 34     for opt in $options; do
 35     if [ `echo $opt | grep '.*-temp-path'` ]; then
 36     value=`echo $opt | cut -d "=" -f 2`
 37     if [ ! -d "$value" ]; then
 38     # echo "creating" $value
 39     mkdir -p $value && chown -R $user $value
 40     fi
 41     fi
 42     done
 43 }
 44  
 45 start() {
 46     [ -x $nginx ] || exit 5
 47     [ -f $NGINX_CONF_FILE ] || exit 6
 48     make_dirs
 49     echo -n $"Starting $prog: "
 50     daemon $nginx -c $NGINX_CONF_FILE
 51     retval=$?
 52     echo
 53     [ $retval -eq 0 ] && touch $lockfile
 54     return $retval
 55 }
 56  
 57 stop() {
 58     echo -n $"Stopping $prog: "
 59     killproc $prog -QUIT
 60     retval=$?
 61     echo
 62     [ $retval -eq 0 ] && rm -f $lockfile
 63     return $retval
 64 }
 65  
 66 restart() {
 67     #configtest || return $?
 68     stop
 69     sleep 1
 70     start
 71 }
 72  
 73 reload() {
 74     #configtest || return $?
 75     echo -n $"Reloading $prog: "
 76     killproc $nginx -HUP
 77     RETVAL=$?
 78     echo
 79 }
 80  
 81 force_reload() {
 82     restart
 83 }
 84  
 85 configtest() {
 86     $nginx -t -c $NGINX_CONF_FILE
 87 }
 88  
 89 rh_status() {
 90     status $prog
 91 }
 92  
 93 rh_status_q() {
 94     rh_status >/dev/null 2>&1
 95 }
 96  
 97 case "$1" in
 98 start)
 99 rh_status_q && exit 0
100 $1
101 ;;
102 stop)
103  
104 rh_status_q || exit 0
105 $1
106 ;;
107 restart|configtest)
108 $1
109 ;;
110 reload)
111 rh_status_q || exit 7
112 $1
113 ;;
114 force-reload)
115 force_reload
116 ;;
117 status)
118 rh_status
119 ;;
120 condrestart|try-restart)
121 rh_status_q || exit 0
122 ;;
123 *)
124 echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
125 exit 2
126 esac


 

为启动脚本授权 并加入开机启动

[root@localhost init.d]# chmod -R 777 /etc/rc.d/init.d/nginx 
[root@localhost init.d]# chkconfig  nginx 

[root@localhost init.d]# chmod -R 777 /etc/rc.d/init.d/nginx 
[root@localhost init.d]# chkconfig  nginx

启动Nginx

[root@localhost init.d]# ./nginx start

[root@localhost init.d]# ./nginx start

将Nginx加入系统环境变量

[root@localhost init.d]# echo 'export PATH=$PATH:/usr/local/nginx/sbin'>>/etc/profile && source /etc/profile

[root@localhost init.d]# echo 'export PATH=$PATH:/usr/local/nginx/sbin'>>/etc/profile && source /etc/profile

Nginx命令 [ service nginx (start|stop|restart) ]

[root@localhost init.d]# service nginx start
Starting nginx (via systemctl):                            [  确定  ]

[root@localhost init.d]# service nginx start
Starting nginx (via systemctl):                            [  确定  ]

Tips:快捷命令

service nginx (start|stop|restart)

service nginx (start|stop|restart)

二、KeepAlived安装和配置

1.安装Keepalived依赖环境

yum install -y popt-devel     
yum install  -y ipvsadm
yum install -y libnl*
yum install -y libnf*
yum install -y openssl-devel

2.编译Keepalived并安装

[root@localhost keepalived-1.3.9]# ./configure
[root@localhost keepalived-1.3.9]# make && make install 
[root@localhost keepalived-1.3.9]# ./configure
[root@localhost keepalived-1.3.9]# make && make install

3.将Keepalive 安装成系统服务

[root@localhost etc]# mkdir /etc/keepalived
[root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf  /etc/keepalived/

[root@localhost etc]# mkdir /etc/keepalived
[root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf  /etc/keepalived/

手动复制默认的配置文件到默认路径

[root@localhost etc]#  mkdir /etc/keepalived
[root@localhost etc]# cp /usr/local/keepalived/etc/sysconfig/keepalived  /etc/sysconfig/
[root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

[root@localhost etc]#  mkdir /etc/keepalived
[root@localhost etc]# cp /usr/local/keepalived/etc/sysconfig/keepalived  /etc/sysconfig/
[root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

为keepalived 创建软链接

[root@localhost sysconfig]# ln -s /usr/local/keepalived/sbin/keepalived  /usr/sbin/

[root@localhost sysconfig]# ln -s /usr/local/keepalived/sbin/keepalived  /usr/sbin/

设置Keepalived开机自启动

[root@localhost sysconfig]# chkconfig keepalived  on
注意：正在将请求转发到“systemctl enable keepalived.service”。
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service

启动Keepalived服务

[root@localhost keepalived]# keepalived -D  -f /etc/keepalived/keepalived.conf


[root@localhost keepalived]# keepalived -D  -f /etc/keepalived/keepalived.conf

关闭Keepalived服务

[root@localhost keepalived]# killall keepalived

[root@localhost keepalived]# killall keepalived

三、集群规划和搭建


 


keepalived如何升级版本_keepalived如何升级版本_04


集群规划图片


环境准备：

CentOS 7.2 

Keepalived   Version 1.4.0 - December 29, 2017 

Nginx           Version: nginx/1.12.2 

Tomcat         Version:8

集群规划清单

虚拟机

IP

说明

Keepalived+Nginx1[Master]

192.168.43.101

Nginx Server 01

Keeepalived+Nginx[Backup]

192.168.43.102

Nginx Server 02

Tomcat01

192.168.43.103

Tomcat Web Server01

Tomcat02

192.168.43.104

Tomcat Web Server02

VIP

192.168.43.150

虚拟漂移IP

1.更改Tomcat默认欢迎页面，用于标识切换Web

更改TomcatServer01 节点ROOT/index.jsp 信息，加入TomcatIP地址，并加入Nginx值，即修改节点192.168.43.103信息如下：

<div id="asf-box">
    <h1>${pageContext.servletContext.serverInfo}(192.168.224.103)<%=request.getHeader("X-NGINX")%></h1> </div>

更改TomcatServer02 节点ROOT/index.jsp信息，加入TomcatIP地址，并加入Nginx值，即修改节点192.168.43.104信息如下：

<div id="asf-box">
    <h1>${pageContext.servletContext.serverInfo}(192.168.224.104)<%=request.getHeader("X-NGINX")%></h1> </div>

2.启动Tomcat服务，查看Tomcat服务IP信息，此时Nginx未启动，因此request-header没有Nginx信息。


 


keepalived如何升级版本_nginx_05


Tomcat启动信息


3.配置Nginx代理信息

1.配置Master节点[192.168.43.101]代理信息
upstream tomcat {
   server 192.168.43.103:8080 weight=1; server 192.168.43.104:8080 weight=1; } server{ location / { proxy_pass http://tomcat; proxy_set_header X-NGINX "NGINX-1"; } #......其他省略 }
2.配置Backup节点[192.168.43.102]代理信息
upstream tomcat {
    server 192.168.43.103:8080 weight=1; server 192.168.43.104:8080 weight=1; } server{ location / { proxy_pass http://tomcat; proxy_set_header X-NGINX "NGINX-2"; } #......其他省略 }
3.启动Master 节点Nginx服务
[root@localhost init.d]# service nginx start
Starting nginx (via systemctl):                            [  确定  ]

[root@localhost init.d]# service nginx start
Starting nginx (via systemctl):                            [  确定  ]

此时访问 192.168.43.101 可以看到103和104节点Tcomat交替显示，说明Nginx服务已经将请求负载到了2台tomcat上。


 


keepalived如何升级版本_运维_06


Nginx 负载效果


4.同理配置Backup[192.168.43.102] Nginx信息，启动Nginx后，访问192.168.43.102后可以看到Backup节点已起到负载的效果。


 


keepalived如何升级版本_运维_07


Backup负载效果


4.配置Keepalived 脚本信息

1.在Master节点和Slave节点 /etc/keepalived目录下添加check_nginx.sh 文件，用于检测Nginx的存活状况，添加keepalived.conf文件

check_nginx.sh文件信息如下：

#!/bin/bash
#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived if [ $n -eq "0" ]; then /etc/rc.d/init.d/nginx start n2=`ps -C nginx --no-heading|wc -l` if [ $n2 -eq "0" ]; then echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log systemctl stop keepalived fi fi

添加完成后，为check_nginx.sh 文件授权，便于脚本获得执行权限。

[root@localhost keepalived]# chmod -R 777 /etc/keepalived/check_nginx.sh 


[root@localhost keepalived]# chmod -R 777 /etc/keepalived/check_nginx.sh
2.在Master 节点 /etc/keepalived目录下，添加keepalived.conf 文件，具体信息如下：
vrrp_script chk_nginx {  
 script "/etc/keepalived/check_nginx.sh"   //检测nginx进程的脚本  
 interval 2  
 weight -20  
}  

global_defs {  
 notification_email {  
     //可以添加邮件提醒 } } vrrp_instance VI_1 { state MASTER #标示状态为MASTER 备份机为BACKUP interface ens33 #设置实例绑定的网卡(ip addr查看，需要根据个人网卡绑定) virtual_router_id 51 #同一实例下virtual_router_id必须相同 mcast_src_ip 192.168.43.101 priority 250 #MASTER权重要高于BACKUP 比如BACKUP为240 advert_int 1 #MASTER与BACKUP负载均衡器之间同步检查的时间间隔，单位是秒 nopreempt #非抢占模式 authentication { #设置认证 auth_type PASS #主从服务器验证方式 auth_pass 123456 } track_script { check_nginx } virtual_ipaddress { #设置vip 192.168.43.150 #可以多个虚拟IP，换行即可 } }
3.在Backup节点 etc/keepalived目录下添加 keepalived.conf 配置文件

信息如下：

vrrp_script chk_nginx {  
 script "/etc/keepalived/check_nginx.sh"   //检测nginx进程的脚本  
 interval 2  
 weight -20  
}  

global_defs {  
 notification_email {  
     //可以添加邮件提醒 } } vrrp_instance VI_1 { state BACKUP #标示状态为MASTER 备份机为BACKUP interface ens33 #设置实例绑定的网卡(ip addr查看) virtual_router_id 51 #同一实例下virtual_router_id必须相同 mcast_src_ip 192.168.43.102 priority 240 #MASTER权重要高于BACKUP 比如BACKUP为240 advert_int 1 #MASTER与BACKUP负载均衡器之间同步检查的时间间隔，单位是秒 nopreempt #非抢占模式 authentication { #设置认证 auth_type PASS #主从服务器验证方式 auth_pass 123456 } track_script { check_nginx } virtual_ipaddress { #设置vip 192.168.43.150 #可以多个虚拟IP，换行即可 } }

Tips:关于配置信息的几点说明

  • state - 主服务器需配成MASTER，从服务器需配成BACKUP
  • interface - 这个是网卡名，我使用的是VM12.0的版本，所以这里网卡名为ens33
  • mcast_src_ip - 配置各自的实际IP地址
  • priority - 主服务器的优先级必须比从服务器的高，这里主服务器配置成250，从服务器配置成240
  • virtual_ipaddress - 配置虚拟IP（192.168.43.150）
  • authentication - auth_pass主从服务器必须一致，keepalived靠这个来通信
  • virtual_router_id - 主从服务器必须保持一致

5.集群高可用(HA)验证

  • Step1 启动Master机器的Keepalived和 Nginx服务
[root@localhost keepalived]# keepalived  -D -f /etc/keepalived/keepalived.conf
[root@localhost keepalived]# service nginx start

[root@localhost keepalived]# keepalived  -D -f /etc/keepalived/keepalived.conf
[root@localhost keepalived]# service nginx start

查看服务启动进程

[root@localhost keepalived]# ps -aux|grep nginx
root       6390  0.0  0.0  20484   612 ?        Ss   19:13   0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
nobody     6392  0.0  0.0  23008  1628 ?        S    19:13   0:00 nginx: worker process
root       6978  0.0  0.0 112672   968 pts/0    S+   20:08   0:00 grep --color=auto nginx

查看Keepalived启动进程

[root@localhost keepalived]# ps -aux|grep keepalived
root       6402  0.0  0.0 45920 1016 ? Ss 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf root 6403 0.0 0.0 48044 1468 ? S 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf root 6404 0.0 0.0 50128 1780 ? S 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf root 7004 0.0 0.0 112672 976 pts/0 S+ 20:10 0:00 grep --color=auto keepalived 
[root@localhost keepalived]# ps -aux|grep keepalived
root       6402  0.0  0.0 45920 1016 ? Ss 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf root 6403 0.0 0.0 48044 1468 ? S 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf root 6404 0.0 0.0 50128 1780 ? S 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf root 7004 0.0 0.0 112672 976 pts/0 S+ 20:10 0:00 grep --color=auto keepalived

使用 ip add 查看虚拟IP绑定情况，如出现192.168.43.150 节点信息则绑定到Master节点

[root@localhost keepalived]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 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 qlen 1000 link/ether 00:0c:29:91:bf:59 brd ff:ff:ff:ff:ff:ff inet 192.168.43.101/24 brd 192.168.43.255 scope global ens33 valid_lft forever preferred_lft forever inet 192.168.43.150/32 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::9abb:4544:f6db:8255/64 scope link valid_lft forever preferred_lft forever inet6 fe80::b0b3:d0ca:7382:2779/64 scope link tentative dadfailed valid_lft forever preferred_lft forever inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link tentative dadfailed valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff 
[root@localhost keepalived]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 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 qlen 1000 link/ether 00:0c:29:91:bf:59 brd ff:ff:ff:ff:ff:ff inet 192.168.43.101/24 brd 192.168.43.255 scope global ens33 valid_lft forever preferred_lft forever inet 192.168.43.150/32 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::9abb:4544:f6db:8255/64 scope link valid_lft forever preferred_lft forever inet6 fe80::b0b3:d0ca:7382:2779/64 scope link tentative dadfailed valid_lft forever preferred_lft forever inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link tentative dadfailed valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff
  • Step 2 启动Backup节点Nginx服务和Keepalived服务，查看服务启动情况，如Backup节点出现了虚拟IP，则Keepalvied配置文件有问题，此情况称为脑裂。
[root@localhost keepalived]# clear
[root@localhost keepalived]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 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 qlen 1000 link/ether 00:0c:29:14:df:79 brd ff:ff:ff:ff:ff:ff inet 192.168.43.102/24 brd 192.168.43.255 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff 
[root@localhost keepalived]# clear
[root@localhost keepalived]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 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 qlen 1000 link/ether 00:0c:29:14:df:79 brd ff:ff:ff:ff:ff:ff inet 192.168.43.102/24 brd 192.168.43.255 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff
  • Step 3 验证服务

    浏览并多次强制刷新地址： http://192.168.43.150 ,可以看到103和104多次交替显示，并显示Nginx-1,则表明 Master节点在进行web服务转发。
  • Step 4 关闭Master keepalived服务和Nginx服务，访问Web服务观察服务转移情况
[root@localhost keepalived]# killall keepalived
[root@localhost keepalived]# service nginx stop

[root@localhost keepalived]# killall keepalived
[root@localhost keepalived]# service nginx stop

此时强制刷新192.168.43.150发现 页面交替显示103和104并显示Nginx-2 ，VIP已转移到192.168.43.102上，已证明服务自动切换到备份节点上。

  • Step 5 启动Master Keepalived 服务和Nginx服务

    此时再次验证发现，VIP已被Master重新夺回，并页面交替显示 103和104，此时显示Nginx-1

四、Keepalived抢占模式和非抢占模式

keepalived的HA分为抢占模式和非抢占模式，抢占模式即MASTER从故障中恢复后，会将VIP从BACKUP节点中抢占过来。非抢占模式即MASTER恢复后不抢占BACKUP升级为MASTER后的VIP。 

非抢占模式配置：

  • 1> 在vrrp_instance块下两个节点各增加了nopreempt指令，表示不争抢vip
  • 2> 节点的state都为BACKUP
    两个keepalived节点都启动后，默认都是BACKUP状态，双方在发送组播信息后，会根据优先级来选举一个MASTER出来。由于两者都配置了nopreempt，所以MASTER从故障中恢复后，不会抢占vip。这样会避免VIP切换可能造成的服务延迟。