| 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。
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 ]
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。
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。
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的存货状况，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
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
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
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
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
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
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
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。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
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