实验架构图：
实验环境
Nginx和Keepalived原理介绍
参考博客：http://467754239.blog.51cto.com/4878013/1541421
1、nginx
Nginx进程基于于Master+Slave(worker)多进程模型，自身具有非常稳定的子进程管理功能。在Master进程分配模式下，Master进程永远不进行业务处理，只是进行任务分发，
从而达到Master进程的存活高可靠性，Slave(worker)进程所有的业务信号都 由主进程发出，Slave(worker)进程所有的超时任务都会被Master中止，属于非阻塞式任务模型。
2、keepalived
Keepalived是Linux下面实现VRRP 备份路由的高可靠性运行件。基于Keepalived设计的服务模式能够真正做到主服务器和备份服务器故障时IP瞬间无缝交接,作用:
主要用作RealServer的健康状态检查以及LoadBalance主机和BackUP主机之间failover的实现
3、单点故障
Nginx有很强代理功能，但是一台nginx就形成了单点，现在使用keepalived来解决这个问题，keepalived的故障转移时间很短.
Nginx+keepalived双机实现nginx反向代理服务的高可用,一台nginx挂掉之后不影响应用也不影响内网访问外网.
4、此架构需要考虑的问题
1) Master没挂，则Master占有vip且nginx运行在Master上
2) Master挂了，则backup抢占vip且在backup上运行nginx服务
3) 如果master服务器上的nginx服务挂了，则vip资源转移到backup服务器上
4) 检测后端服务器的健康状态
5、叙述
Master和Backup两边都开启nginx服务，无论Master还是Backup，当其中的一个keepalived服务停止后，vip都会漂移到keepalived服务还在的节点上，
如果要想使nginx服务挂了，vip也漂移到另一个节点，则必须用脚本或者在配置文件里面用shell命令来控制。
首先必须明确后端服务器的健康状态检测keepalived在这种架构上是无法检测的，后端服务器的健康状态检测是有nginx来判断的，但是nginx的检测机制有一定的缺陷，后端服务器某一个宕机之后，nginx还是会分发请求给它，在一定的时间内后端服务响应不了，nginx则会发给另外一个服务器，然后当客户的请求来了，nginx会一段时间内不会把请求分发给已经宕机的服务器，但是过一段时间后，nginx还是会把分发请求发给宕机的服务器上。
实验实现：
HA高可用集群构建前提：
1.proxy和proxy2节点时间必须同步；
建议使用ntp协议进行；
参考博客：http://sohudrgon.blog.51cto.com/3088108/1598314
2、节点之间必须要通过主机名互相通信；
建议使用hosts文件；
通信中使用的名字必须与其节点为上“uname -n”命令展示出的名字保持一致；
[root@proxy ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
172.16.0.1 server.magelinux.com server
172.16.31.52 proxy.stu31.com proxy
172.16.31.53 proxy2.stu31.com proxy2
172.16.31.50 tom1.stu31.com tom1
172.16.31.51 tom2.stu31.com tom2
3、节点之间彼此root用户能基于ssh密钥方式进行通信；
节点proxy：
# ssh-keygen -t rsa -P ""
# ssh-copy-id -i .ssh/id_rsa.pub proxy2
节点proxy2：
# ssh-keygen -t rsa -P ""
# ssh-copy-id -i .ssh/id_rsa.pub proxy
测试ssh无密钥通信：
[root@proxy ~]# date ; ssh proxy2 date
Fri Jan 16 15:38:36 CST 2015
Fri Jan 16 15:38:36 CST 2015
一.安装nginx
1.两个节点都安装nginx
# yum install nginx-1.6.2-1.el6.ngx.x86_64.rpm
2.分别在两台机器上创建不同的测试页面[为了测试]
[root@proxy ~]# echo "Page from nginx1 ,proxy" >/usr/share/nginx/html/index.html
[root@proxy2 ~]# echo "Page from nginx2 ,proxy2" >/usr/share/nginx/html/index.html
3.配置nginx的配置文件
配置nginx服务器将动态内容反向代理到后端tomcat服务器组，而静态内容直接访问本地的nginx服务器；
定义后端tomcat服务器组：
[root@proxy ~]# vim /etc/nginx/nginx.conf
#添加如下后端服务器组
upstream tcsrvs {
ip_hash;
server 172.16.31.50:8080;
server 172.16.31.51:8080;
}
定义反向代理：
[root@proxy nginx]# pwd
/etc/nginx
[root@proxy nginx]# vim conf.d/default.conf
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log /var/log/nginx/log/host.access.log main;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
location ~* \.(jsp|do)$ {
proxy_pass http://tcsrvs;
}
}
3.启动nginx服务访问测试
静态内容是本地nginx提供的页面：
动态页面丢到后端的tomcat服务器了：
到节点tom1和tom2创建tomcat的测试页：
节点tom1：
[root@tom1 testapp]# pwd
/usr/local/tomcat/webapps/ROOT
[root@tom1 testapp]# vim index.jsp
<%@ page language="java" %>
<html>
<head><title>TomcatA</title></head>
<body>
<h1><font color="red">TomcatA.stu31.com</font></h1>
<table align="centre" border="1">
<tr>
<td>Session ID</td>
<% session.setAttribute("stu31.com","stu31.com"); %>
<td><%= session.getId() %></td>
</tr>
<tr>
<td>Created on</td>
<td><%= session.getCreationTime() %></td>
</tr>
</table>
</body>
</html>
节点tom2：
[root@tom2 testapp]# pwd
/usr/local/tomcat/webapps/ROOT
[root@tom2 testapp]# vim index.jsp
<%@ page language="java" %>
<html>
<head><title>TomcatB </title></head>
<body>
<h1><font color="red">TomcatB.stu31.com</font></h1>
<table align="centre" border="1">
<tr>
<td>Session ID</td>
<% session.setAttribute("stu31.com","stu31.com"); %>
<td><%= session.getId() %></td>
</tr>
<tr>
<td>Created on</td>
<td><%= session.getCreationTime() %></td>
</tr>
</table>
</body>
</html>
复制配置文件到节点proxy2：
[root@proxy nginx]# scp nginx.conf proxy2:/etc/nginx/
nginx.conf 100% 740 0.7KB/s 00:00
[root@proxy nginx]# scp conf.d/default.conf proxy2:/etc/nginx/conf.d/
default.conf 100% 1167 1.1KB/s 00:00
二.keepalived安装与配置
CentOS 6.6 是1.2.13版本的keepalived，已经够用了，最新版本的keepalived是1.2.15；
1.两个节点安装keepalived软件
# yum install -y keepalived
2.配置keepalived
修改keepalived配置文件
keepalived的文件路径/etc/keepalived/keepalived.conf
主节点MASTER node：
! Configuration File for keepalived #全局定义
global_defs {
notification_email { #指定keepalived在发生事件时(比如切换),需要发送的email对象,可以多个,每行一个
root@stu31.com
}
notification_email_from kaadmin@stu31.com
smtp_server 127.0.0.1 #指定发送email的smtp服务器
smtp_connect_timeout 30
router_id LVS_DEVEL #运行keepalived的机器的一个标识
}
vrrp_instance VI_1 {
state MASTER #为主服务器
interface eth0 #监听的本地网卡接口
virtual_router_id 100 #主辅virtual_router_id号必须相同
mcast_src_ip=172.16.31.52 #主nginx的ip地址
priority 100 #优先级为100，此值越大优先级越大 就为master 权重值
advert_int 1 #VRRP Multicast 广播周期秒数；心跳检测时间，单位秒
authentication {
auth_type PASS #vrrp认证方式
auth_pass oracle #vrrp口令
}
virtual_ipaddress { #VRRP HA 虚拟地址 如果有多个VIP，继续换行填写
172.16.31.188/24 dev eth0
}
}
备用节点BACKUP node：
global_defs {
notification_email {
root@stu31.com
}
notification_email_from kaadmin@stu31.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 100
mcast_src_ip=172.16.31.53
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass oracle
}
virutal_ipaddress {
172.16.31.188/24 dev eth0
}
}
3.启动keepalived服务
设置keepalived开机启动：
# chkconfig keepalived on
启动两个节点的keepalived服务：
[root@proxy ~]# service keepalived start ; ssh proxy2 "service keepalived start"
4.查看vip状态
#首先在master节点上查看vip的状态
[root@proxy keepalived]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:3b:23:60 brd ff:ff:ff:ff:ff:ff
inet 172.16.31.52/16 brd 172.16.255.255 scope global eth0
inet 172.16.31.188/16 scope global secondary eth0
inet6 fe80::a00:27ff:fe3b:2360/64 scope link
valid_lft forever preferred_lft forever
#其次在backup节点上查看vip的状态
[root@proxy2 keepalived]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:6e:bd:28 brd ff:ff:ff:ff:ff:ff
inet 172.16.31.53/16 brd 172.16.255.255 scope global eth0
inet6 fe80::a00:27ff:fe6e:bd28/64 scope link
valid_lft forever preferred_lft forever
5.查看keepalived服务启动后选举VIP的过程日志：
MASTER节点的日志：
当启动keepalived服务的时候，会根据配置文件的优先级来竞选谁为master，从日志来看172.16.31.52竞选master
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 16:31:06 proxy Keepalived[5807]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 16:31:06 proxy Keepalived[5809]: Starting Healthcheck child process, pid=5811
Jan 16 16:31:06 proxy Keepalived[5809]: Starting VRRP child process, pid=5812
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Registering Kernel netlink reflector
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Registering Kernel netlink command channel
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Registering Kernel netlink reflector
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Registering Kernel netlink command channel
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Registering gratuitous ARP shared channel
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Configuration is using : 62912 Bytes
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: Using LinkWatch kernel netlink reflector...
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Configuration is using : 7455 Bytes
Jan 16 16:31:06 proxy Keepalived_healthcheckers[5811]: Using LinkWatch kernel netlink reflector...
Jan 16 16:31:06 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 16:31:07 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 16:31:07 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 16:31:07 proxy Keepalived_healthcheckers[5811]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 16:31:07 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 16:31:07 proxy Keepalived_vrrp[5812]: receive an invalid ip number count associated with VRID!
Jan 16 16:31:07 proxy Keepalived_vrrp[5812]: bogus VRRP packet received on eth0 !!!
Jan 16 16:31:07 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Dropping received VRRP packet...
Jan 16 16:31:08 proxy Keepalived_vrrp[5812]: receive an invalid ip number count associated with VRID!
Jan 16 16:31:08 proxy Keepalived_vrrp[5812]: bogus VRRP packet received on eth0 !!!
Jan 16 16:31:08 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Dropping received VRRP packet...
Jan 16 16:31:09 proxy Keepalived_vrrp[5812]: receive an invalid ip number count associated with VRID!
Jan 16 16:31:09 proxy Keepalived_vrrp[5812]: bogus VRRP packet received on eth0 !!!
Jan 16 16:31:09 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Dropping received VRRP packet...
Jan 16 16:31:12 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
BACKUP节点的日志；
由于优先级低，就成为了备用节点；
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 16:31:09 proxy2 Keepalived[2176]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 16:31:09 proxy2 Keepalived[2178]: Starting Healthcheck child process, pid=2180
Jan 16 16:31:09 proxy2 Keepalived[2178]: Starting VRRP child process, pid=2181
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Registering Kernel netlink reflector
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Registering Kernel netlink command channel
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Registering Kernel netlink reflector
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Registering Kernel netlink command channel
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Registering gratuitous ARP shared channel
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Configuration is using : 7455 Bytes
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Configuration is using : 62912 Bytes
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: Using LinkWatch kernel netlink reflector...
Jan 16 16:31:09 proxy2 Keepalived_healthcheckers[2180]: Using LinkWatch kernel netlink reflector...
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 16 16:31:09 proxy2 Keepalived_vrrp[2181]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
6.我们停止MASTER节点的keepalived服务，那么BACKUP节点会成为主节点。
主节点停止keepalived服务：
[root@proxy keepalived]# service keepalived stop
Stopping keepalived: [ OK ]
我们通过日志来查看自动切换的过程：
主节点的VIP自动移除：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 16:37:33 proxy Keepalived[5809]: Stopping Keepalived v1.2.13 (10/15,2014)
Jan 16 16:37:33 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) sending 0 priority
Jan 16 16:37:33 proxy Keepalived_vrrp[5812]: VRRP_Instance(VI_1) removing protocol VIPs.
Jan 16 16:37:33 proxy Keepalived_healthcheckers[5811]: Netlink reflector reports IP 172.16.31.188 removed
备用节点自动竞选成主节点，获取VIP：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 16:37:34 proxy2 Keepalived_vrrp[2181]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 16:37:35 proxy2 Keepalived_vrrp[2181]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 16:37:35 proxy2 Keepalived_vrrp[2181]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 16:37:35 proxy2 Keepalived_vrrp[2181]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 16:37:35 proxy2 Keepalived_healthcheckers[2180]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 16:37:40 proxy2 Keepalived_vrrp[2181]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
7.我们将主节点重新启动，并测试节点主备切换时间：
[root@proxy keepalived]# service keepalived start
Starting keepalived: [ OK ]
我在物理机上测试主备切换时间，间隔差不多一秒钟左右：
C:\Users\GuoGang>ping -t 172.16.31.188
正在 Ping 172.16.31.188 具有 32 字节的数据:
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
请求超时。
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
来自 172.16.31.188 的回复: 字节=32 时间<1ms TTL=64
172.16.31.188 的 Ping 统计信息:
数据包: 已发送 = 9，已接收 = 8，丢失 = 1 (11% 丢失)，
8.更改DNS服务器的IP为虚拟ip
DNS服务器构建请参考博客：http://sohudrgon.blog.51cto.com/3088108/1588344
# vim /var/named/stu31.com.zone
$TTL 600
$ORIGIN stu31.com.
@ IN SOA ns1.stu31.com. root.stu31.com. (
2014121801
1D
5M
1W
1H)
@ IN NS ns1.stu31.com.
ns1 IN A 172.16.31.52
www IN A 172.16.31.188
重启named服务器；
9.访问测试：
三.Keepalived服务根据nginx状态实现自动切换配置
1.默认情况下，keepalived工作模式并不能直接监控nginx服务，只有当keepalived服务挂掉后才能主备切换，nginx服务挂掉后不能实现主备服务器的切换，但是我们的目的就是要实现nginx服务keepalived挂掉后，都要主备切换。
以上有两种方法可以实现
A.keepalived配置文件中可以支持shell脚本，写个监听nginx服务的脚本就可以了
B.单独写个脚本来监听nginx和keepalived服务
keepalived的样板文件中有配置文件专门探测服务正常与否：
[root@proxy keepalived]# ls /usr/share/doc/keepalived-1.2.13/samples/
keepalived.conf.fwmark keepalived.conf.track_interface
keepalived.conf.HTTP_GET.port keepalived.conf.virtualhost
keepalived.conf.inhibit keepalived.conf.virtual_server_group
keepalived.conf.IPv6 keepalived.conf.vrrp
keepalived.conf.misc_check keepalived.conf.vrrp.localcheck
keepalived.conf.misc_check_arg keepalived.conf.vrrp.lvs_syncd
keepalived.conf.quorum keepalived.conf.vrrp.routes
keepalived.conf.sample keepalived.conf.vrrp.scripts
keepalived.conf.SMTP_CHECK keepalived.conf.vrrp.static_ipaddress
keepalived.conf.SSL_GET keepalived.conf.vrrp.sync
keepalived.conf.status_code sample.misccheck.smbcheck.sh
就是keepalived.conf.vrrp.localcheck这个样例文件中讲解了所有的探测服务正常与否的方法；
2.基于第一种情况我们在keepalived的配置文件中加入如下探测nginx服务是否正常：
主备节点都需要添加：
vrrp_script
chk_nginx { #检测nginx服务是否在运行有很多方式，比如进程，用脚本检测等等
script "killall -0 nginx" #用shell命令检查nginx服务是否存在
interval 1 #时间间隔为1秒检测一次
weight -2 #当nginx的服务不存在了，就把当前的权重-2
fall 2 #测试失败的次数
rise 1 #测试成功的次数
}
然后在vrrp_instance配置段中引用定义的脚本名称；
track_script {
chk_nginx #引用上面的vrrp_script定义的脚本名称
}
实例测试：
MASTER节点的配置文件：
[root@proxy keepalived]# cat keepalived.conf
global_defs {
notification_email {
root@stu31.com
}
notification_email_from kaadmin@stu31.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx { #检测nginx服务是否在运行有很多方式，比如进程，用脚本检测等等
script "killall -0 nginx" #用shell命令检查nginx服务是否存在
interval 1 #时间间隔为1秒检测一次
weight -2 #当nginx的服务不存在了，就把当前的权重-2
fall 2 #测试失败的次数
rise 1 #测试成功的次数
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 100
mcast_src_ip=172.16.31.52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass oracle
}
virtual_ipaddress {
172.16.31.188/16 dev eth0
}
track_script {
chk_nginx #引用上面的vrrp_script定义的脚本名称
}
}
BACKUP节点的配置文件：
[root@proxy2 keepalived]# cat keepalived.conf
global_defs {
notification_email {
root@stu31.com
}
notification_email_from kaadmin@stu31.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx { #检测nginx服务是否在运行有很多方式，比如进程，用脚本检测等等
script "killall -0 nginx" #用shell命令检查nginx服务是否存在
interval 1 #时间间隔为1秒检测一次
weight -2 #当nginx的服务不存在了，就把当前的权重-2
fall 2 #测试失败的次数
rise 1 #测试成功的次数
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 100
mcast_src_ip=172.16.31.53
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass oracle
}
virtual_ipaddress {
172.16.31.188/16 dev eth0
}
track_script {
chk_nginx #引用上面的vrrp_script定义的脚本名称
}
}
重启keepalived服务；我们将主节点的nginx服务停止；测试keepalived服务是否自动切换到备用节点：
重启服务；
[root@proxy keepalived]# service keepalived restart ; ssh proxy2 "service keepalived restart"
Stopping keepalived: [ OK ]
Starting keepalived: [ OK ]
Stopping keepalived: [ OK ]
Starting keepalived: [ OK ]
查看日志可以发现已经在检查nginx服务了：
MASTE节点的启动日志：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 17:18:02 proxy Keepalived[6098]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 17:18:02 proxy Keepalived[6100]: Starting Healthcheck child process, pid=6102
Jan 16 17:18:02 proxy Keepalived[6100]: Starting VRRP child process, pid=6104
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Registering Kernel netlink reflector
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Registering Kernel netlink reflector
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Registering Kernel netlink command channel
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Registering Kernel netlink command channel
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Registering gratuitous ARP shared channel
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Configuration is using : 7495 Bytes
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Configuration is using : 65170 Bytes
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: Using LinkWatch kernel netlink reflector...
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Jan 16 17:18:02 proxy Keepalived_healthcheckers[6102]: Using LinkWatch kernel netlink reflector...
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: VRRP_Script(chk_nginx) succeeded
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 17:18:02 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) Received lower prio advert, forcing new election
Jan 16 17:18:03 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 17:18:03 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 17:18:03 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 17:18:03 proxy Keepalived_healthcheckers[6102]: Netlink reflector reports IP 172.16.31.188 added
BACKUP节点的启动日志：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 17:18:03 proxy2 Keepalived[25883]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 17:18:03 proxy2 Keepalived[25885]: Starting Healthcheck child process, pid=25887
Jan 16 17:18:03 proxy2 Keepalived[25885]: Starting VRRP child process, pid=25888
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Registering Kernel netlink reflector
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Registering Kernel netlink reflector
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Registering Kernel netlink command channel
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Registering Kernel netlink command channel
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Registering gratuitous ARP shared channel
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Configuration is using : 7495 Bytes
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Configuration is using : 65170 Bytes
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: Using LinkWatch kernel netlink reflector...
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Jan 16 17:18:03 proxy2 Keepalived_healthcheckers[25887]: Using LinkWatch kernel netlink reflector...
Jan 16 17:18:03 proxy2 Keepalived_vrrp[25888]: VRRP_Script(chk_nginx) succeeded
只是检测了nginx服务；
我们在MASTER节点关闭nginx服务后观察：
[root@proxy keepalived]# service nginx stop
Stopping nginx: [ OK ]
观察日志，主节点检查服务失败，移除VIP地址；
MASTE节点的启动日志：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 17:21:20 proxy Keepalived_vrrp[6104]: VRRP_Script(chk_nginx) failed
Jan 16 17:21:22 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) Received higher prio advert
Jan 16 17:21:22 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 16 17:21:22 proxy Keepalived_vrrp[6104]: VRRP_Instance(VI_1) removing protocol VIPs.
Jan 16 17:21:22 proxy Keepalived_healthcheckers[6102]: Netlink reflector reports IP 172.16.31.188 removed
备用节点检查nginx服务正常，进行自动加载VIP：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 17:21:22 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) forcing a new MASTER election
Jan 16 17:21:22 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) forcing a new MASTER election
Jan 16 17:21:23 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 17:21:24 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 17:21:24 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 17:21:24 proxy2 Keepalived_healthcheckers[25887]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 17:21:24 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 17:21:29 proxy2 Keepalived_vrrp[25888]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
至此，内置检测脚本测试服务正常与否的设置就成功。
3.基于第二种情况，我们单独写一个脚本来探测nginx服务是否正常；探测nginx进程正常与否
我们需要跟上面的设置区分开来，如果使用独立脚本，上面的内置脚本就不用设置了。
#vim nginxpidcheck.sh
#!/bin/bash
while :
do
nginxpid=`ps -C nginx --no-header | wc -l`
if [ $nginxpid -eq 0 ];then
/usr/local/nginx/sbin/nginx
sleep 5
nginxpid=`ps -C nginx --no-header | wc -l`
echo $nginxpid
if [ $nginxpid -eq 0 ];then
/etc/init.d/keepalived stop
fi
fi
sleep 5
done
我们将脚本制定为任务计划运行即可，我们测试就直接交给后台自动运行：
这是一个无限循环的脚本，放在主Nginx机器上（因为目前主要是由它提供服务），每隔5秒执行一次，用ps -C 命令来收集nginx的PID值到底是否为0，如果是0的话（即Nginx进程死掉了），尝试启动nginx进程；如果继续为0，即nginx启动失改， 则关闭本机的Keeplaived进程，VIP地址则会由备机接管，当然了，整个网站就会由备机的Nginx来提供服务了，这样保证Nginx进程的高可用。
实例测试：
我们将脚本放在/etc/keepalived目录下，两个节点都存放：
[root@proxy2 keepalived]# ls
keepalived.conf nginxpidcheck.sh
直接交给后台自动运行，两个节点都运行：
#nohup sh /etc/keepalived/nginxpidcheck.sh &
我们停止主节点的nginx服务：
[root@proxy keepalived]# service nginx stop
Stopping nginx: [ OK ]
观察日志查看主备切换过程成功与否：
MASTE节点的启动日志：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 17:33:37 proxy Keepalived[7221]: Stopping Keepalived v1.2.13 (10/15,2014)
Jan 16 17:33:37 proxy Keepalived_vrrp[7225]: VRRP_Instance(VI_1) sending 0 priority
Jan 16 17:33:37 proxy Keepalived_vrrp[7225]: VRRP_Instance(VI_1) removing protocol VIPs.
Jan 16 17:33:37 proxy Keepalived_healthcheckers[7224]: Netlink reflector reports IP 172.16.31.188 removed
VIP移除了；
备用节点检查nginx服务正常，进行自动加载VIP：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 17:33:37 proxy2 Keepalived_vrrp[26984]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 17:33:38 proxy2 Keepalived_vrrp[26984]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 17:33:38 proxy2 Keepalived_vrrp[26984]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 17:33:38 proxy2 Keepalived_healthcheckers[26983]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 17:33:38 proxy2 Keepalived_vrrp[26984]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 17:33:43 proxy2 Keepalived_vrrp[26984]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
访问测试，静态内容是转到了节点proxy2上了：
4.基于邮件通知形式的自动切换主备节点的脚本构建
邮件通知脚本构建：将脚本放置在/etc/keepalived/下，两个节点都需要创建
[root@proxy keepalived]# vim notify.sh
#!/bin/bash
vip=172.16.31.188
contact='root@localhost'
notify() {
mailsubject="`hostname` to be $1: $vip floating"
mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"
echo $mailbody | mail -s "$mailsubject" $contact
}
case "$1" in
master)
notify master
/etc/rc.d/init.d/nginx start
exit 0
;;
backup)
notify backup
/etc/rc.d/init.d/nginx stop
exit 0
;;
fault)
notify fault
/etc/rc.d/init.d/nginx stop
exit 0
;;
*)
echo 'Usage: `basename $0` {master|backup|fault}'
exit 1
;;
esac
如果是主MASTER节点，我们就启动nginx服务；如果是BACKUP备用节点我们就停止nginx服务；如果节点故障，我们停止nginx服务；
需要在keepalived配置文件中进行脚本调用：
MASTER节点：
[root@proxy keepalived]# cat keepalived.conf
global_defs {
notification_email {
root@stu31.com
}
notification_email_from kaadmin@stu31.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_maintance_down { #检查脚本，如果存在down这个文件，就将节点的权重减5
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1 #时间间隔为1秒检测一次
weight -5 #当nginx的服务不存在了，就把当前的权重-5
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 100
mcast_src_ip=172.16.31.52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass oracle
}
virtual_ipaddress {
172.16.31.188/16 dev eth0
}
track_script {
chk_maintance_down #引用上面的vrrp_script定义的脚本名称
}
#如果脚本检查到节点是主节点，就邮件通知管理员，并启动nginx服务器
notify_master "/etc/keepalived/notify.sh master"
#如果脚本检查到节点是备用节点，就邮件通知管理员，并停止nginx服务器
notify_backup "/etc/keepalived/notify.sh backup"
#如果脚本检查到节点是故障节点，就邮件通知管理员，并停止nginx服务器
notify_fault "/etc/keepalived/notify.sh fault"
}
BACKUP节点也设置如下：
[root@proxy2 keepalived]# cat keepalived.conf
global_defs {
notification_email {
root@stu31.com
}
notification_email_from kaadmin@stu31.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_maintance_down {
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -5
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 100
mcast_src_ip=172.16.31.53
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass oracle
}
virtual_ipaddress {
172.16.31.188/16 dev eth0
}
track_script {
chk_maintance_down
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
我们重启keepalived服务器；观察节点的选举情况，
MASTER节点的日志：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 18:09:36 proxy Keepalived[10991]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 18:09:36 proxy Keepalived[10993]: Starting Healthcheck child process, pid=10996
Jan 16 18:09:36 proxy Keepalived[10993]: Starting VRRP child process, pid=10997
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Registering Kernel netlink reflector
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Registering Kernel netlink command channel
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Configuration is using : 7599 Bytes
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Registering Kernel netlink reflector
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Registering Kernel netlink command channel
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Registering gratuitous ARP shared channel
Jan 16 18:09:36 proxy Keepalived_healthcheckers[10996]: Using LinkWatch kernel netlink reflector...
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Configuration is using : 65356 Bytes
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: Using LinkWatch kernel netlink reflector...
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
#检查出无down这个文件；
Jan 16 18:09:36 proxy Keepalived_vrrp[10997]: VRRP_Script(chk_maintance_down) succeeded
Jan 16 18:09:37 proxy Keepalived_vrrp[10997]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 18:09:38 proxy Keepalived_vrrp[10997]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 18:09:38 proxy Keepalived_vrrp[10997]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 18:09:38 proxy Keepalived_vrrp[10997]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 18:09:38 proxy Keepalived_healthcheckers[10996]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 18:09:43 proxy Keepalived_vrrp[10997]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
BACKUP节点的日志：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 18:09:36 proxy2 Keepalived[29190]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 18:09:36 proxy2 Keepalived[29192]: Starting Healthcheck child process, pid=29194
Jan 16 18:09:36 proxy2 Keepalived[29192]: Starting VRRP child process, pid=29195
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Registering Kernel netlink reflector
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Registering Kernel netlink command channel
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Registering Kernel netlink reflector
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Registering Kernel netlink command channel
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Registering gratuitous ARP shared channel
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Configuration is using : 7599 Bytes
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Configuration is using : 65356 Bytes
Jan 16 18:09:36 proxy2 Keepalived_healthcheckers[29194]: Using LinkWatch kernel netlink reflector...
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: Using LinkWatch kernel netlink reflector...
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Jan 16 18:09:36 proxy2 Keepalived_vrrp[29195]: VRRP_Script(chk_maintance_down) succeeded
Jan 16 18:09:43 proxy2 Keepalived[29192]: Stopping Keepalived v1.2.13 (10/15,2014)
查看邮件：
MASTER主节点的邮件：
[root@proxy keepalived]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 2 messages 2 new
>N 1 root Fri Jan 16 18:08 18/696 "proxy.stu31.com to be master: 172.16.31.188 floating"
N 2 root Fri Jan 16 18:09 18/696 "proxy.stu31.com to be master: 172.16.31.188 floating"
& 2
Message 2:
From root@proxy.stu31.com Fri Jan 16 18:09:38 2015
Return-Path: <root@proxy.stu31.com>
X-Original-To: root@localhost
Delivered-To: root@localhost.stu31.com
Date: Fri, 16 Jan 2015 18:09:38 +0800
To: root@localhost.stu31.com
Subject: proxy.stu31.com to be master: 172.16.31.188 floating
User-Agent: Heirloom mailx 12.4 7/29/08
Content-Type: text/plain; charset=us-ascii
From: root@proxy.stu31.com (root)
Status: R
2015-01-16 18:09:38: vrrp transition, proxy.stu31.com changed to be master
备用节点的邮件：
[root@proxy2 keepalived]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 2 messages 2 new
>N 1 root Fri Jan 16 18:08 18/703 "proxy2.stu31.com to be backup: 172.16.31.188 floating"
N 2 root Fri Jan 16 18:09 18/703 "proxy2.stu31.com to be backup: 172.16.31.188 floating"
& 2
Message 2:
From root@proxy2.stu31.com Fri Jan 16 18:09:36 2015
Return-Path: <root@proxy2.stu31.com>
X-Original-To: root@localhost
Delivered-To: root@localhost.stu31.com
Date: Fri, 16 Jan 2015 18:09:36 +0800
To: root@localhost.stu31.com
Subject: proxy2.stu31.com to be backup: 172.16.31.188 floating
User-Agent: Heirloom mailx 12.4 7/29/08
Content-Type: text/plain; charset=us-ascii
From: root@proxy2.stu31.com (root)
Status: R
2015-01-16 18:09:36: vrrp transition, proxy2.stu31.com changed to be backup
我们在主节点的/etc/keepalived/目录下创建一个down文件，来观察主节点是否会切换到备用节点：
[root@proxy keepalived]# touch down
查看主节点日志：
MASTER节点的日志：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 19:09:10 proxy Keepalived_vrrp[20675]: VRRP_Script(chk_maintance_down) failed
Jan 16 19:09:12 proxy Keepalived_vrrp[20675]: VRRP_Instance(VI_1) Received higher prio advert
Jan 16 19:09:12 proxy Keepalived_vrrp[20675]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 16 19:09:12 proxy Keepalived_vrrp[20675]: VRRP_Instance(VI_1) removing protocol VIPs.
Jan 16 19:09:12 proxy Keepalived_healthcheckers[20674]: Netlink reflector reports IP 172.16.31.188 removed
BACKUP节点的日志：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 19:09:12 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) forcing a new MASTER election
Jan 16 19:09:12 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) forcing a new MASTER election
Jan 16 19:09:13 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 19:09:14 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 19:09:14 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 19:09:14 proxy2 Keepalived_healthcheckers[2319]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 19:09:14 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 19:09:19 proxy2 Keepalived_vrrp[2320]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.188
查看邮件：
主节点成为了备用节点了：
[root@proxy keepalived]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 4 messages 2 new 3 unread
U 1 root Fri Jan 16 18:08 19/706 "proxy.stu31.com to be master: 172.16.31.188 floating"
2 root Fri Jan 16 18:09 19/707 "proxy.stu31.com to be master: 172.16.31.188 floating"
>N 3 root Fri Jan 16 19:06 18/696 "proxy.stu31.com to be master: 172.16.31.188 floating"
N 4 root Fri Jan 16 19:09 18/696 "proxy.stu31.com to be backup: 172.16.31.188 floating"
& 4
Message 4:
From root@proxy.stu31.com Fri Jan 16 19:09:12 2015
Return-Path: <root@proxy.stu31.com>
X-Original-To: root@localhost
Delivered-To: root@localhost.stu31.com
Date: Fri, 16 Jan 2015 19:09:12 +0800
To: root@localhost.stu31.com
Subject: proxy.stu31.com to be backup: 172.16.31.188 floating
User-Agent: Heirloom mailx 12.4 7/29/08
Content-Type: text/plain; charset=us-ascii
From: root@proxy.stu31.com (root)
Status: R
2015-01-16 19:09:12: vrrp transition, proxy.stu31.com changed to be backup
& quit
备用节点成为了主节点了：
[root@proxy2 keepalived]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 5 messages 3 new 4 unread
U 1 root Fri Jan 16 18:08 19/713 "proxy2.stu31.com to be backup: 172.16.31.188 floating"
2 root Fri Jan 16 18:09 19/714 "proxy2.stu31.com to be backup: 172.16.31.188 floating"
>N 3 root Fri Jan 16 19:06 18/703 "proxy2.stu31.com to be backup: 172.16.31.188 floating"
N 4 root Fri Jan 16 19:06 18/703 "proxy2.stu31.com to be backup: 172.16.31.188 floating"
N 5 root Fri Jan 16 19:09 18/703 "proxy2.stu31.com to be master: 172.16.31.188 floating"
& 5
Message 5:
From root@proxy2.stu31.com Fri Jan 16 19:09:14 2015
Return-Path: <root@proxy2.stu31.com>
X-Original-To: root@localhost
Delivered-To: root@localhost.stu31.com
Date: Fri, 16 Jan 2015 19:09:14 +0800
To: root@localhost.stu31.com
Subject: proxy2.stu31.com to be master: 172.16.31.188 floating
User-Agent: Heirloom mailx 12.4 7/29/08
Content-Type: text/plain; charset=us-ascii
From: root@proxy2.stu31.com (root)
Status: R
2015-01-16 19:09:14: vrrp transition, proxy2.stu31.com changed to be master
& quit
我们在查看一下nginx服务的启动状况：
主节点的nginx服务状态是停止的：
[root@proxy keepalived]# service nginx status
nginx is stopped
备用节点的nginx服务状态是启动的：
[root@proxy2 keepalived]# service nginx status
nginx (pid 2679) is running...
至此，基于nginx+keepalived构建主备负载均衡代理服务器的实验就完成了。
四.双主模式构建
两个keepalived节点互为主备节点的模式构建；
实例配置文件：
proxy节点：
[root@proxy keepalived]# cat keepalived.conf
global_defs {
notification_email { #通知邮件地址
root@localhost
}
notification_email_from root@localhost
smtp_server 127.0.0.1 #邮件服务器地址
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#
vrrp_script chk_nginx {
script "killall -0 nginx" #服务探测，返回0说明服务是正常的
interval 1 #每隔1秒探测一次
weight -2 #nginx服务下线，权重减2
}
#
vrrp_instance VI_1 { #双主实例1
state MASTER #proxy（172.16.31.52）为主，proxy2（172.16.31.53）为备
interface eth0
virtual_router_id 88 #实例1的VRID为88
garp_master_delay 1
priority 100 #主（172.16.31.52）的优先级为100，从的（172.16.31.52）优先级为99
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
#
virtual_ipaddress {
172.16.31.88/16 dev eth0 #实例1的VIP
}
track_interface {
eth0
}
#
track_script { #脚本追踪
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance VI_2 {
state BACKUP #实例2在proxy（172.16.31.52）上是备，在proxy2（172.16.31.53）上是主
interface eth0
virtual_router_id 188 #实例2的VRID是188
garp_master_delay 1
priority 200 #实例2在proxy上的优先级是200，在proxy2上的优先级是201
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
#
virtual_ipaddress {
172.16.31.188/16 dev eth0 #实例2的VIP
}
track_interface {
eth0
}
track_script { #脚本追踪
chk_nginx
}
}
proxy2节点的配置文件：
[root@proxy2 keepalived]# cat keepalived.conf
global_defs {
notification_email { #通知邮件地址
root@localhost
}
notification_email_from root@localhost
smtp_server 127.0.0.1 #邮件服务器地址
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#
vrrp_script chk_nginx {
script "killall -0 nginx" #服务探测，返回0说明服务是正常的
interval 1 #每隔1秒探测一次
weight -2 #nginx服务下线，权重减2
}
#
vrrp_instance VI_1 { #双主实例1
state BACKUP #proxy（172.16.31.52）为主，proxy2（172.16.31.53）为备
interface eth0
virtual_router_id 88 #实例1的VRID为88
garp_master_delay 1
priority 99 #主（172.16.31.52）的优先级为100，从的（172.16.31.52）优先级为99
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
#
virtual_ipaddress {
172.16.31.88/16 dev eth0 #实例1的VIP
}
track_interface {
eth0
}
#
track_script { #脚本追踪
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance VI_2 {
state MASTER #实例2在proxy（172.16.31.52）上是备，在proxy2（172.16.31.53）上是主
interface eth0
virtual_router_id 188 #实例2的VRID是188
garp_master_delay 1
priority 201 #实例2在proxy上的优先级是200，在proxy2上的优先级是201
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
#
virtual_ipaddress {
172.16.31.188/16 dev eth0 #实例2的VIP
}
track_interface {
eth0
}
track_script { #脚本追踪
chk_nginx
}
}
启动keepalived服务：
[root@proxy keepalived]# service keepalived start ; ssh proxy2 "service keepalived start"
Starting keepalived: [ OK ]
Starting keepalived: [ OK ]
查看启动日志：
从中发现该节点将本该属于proxy2节点的VIP抢占过来了，能proxy节点出现问题了;去查看一下：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 20:19:06 proxy Keepalived[25249]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 20:19:06 proxy Keepalived[25251]: Starting Healthcheck child process, pid=25254
Jan 16 20:19:06 proxy Keepalived[25251]: Starting VRRP child process, pid=25255
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Netlink reflector reports IP 172.16.31.52 added
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Registering Kernel netlink reflector
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Registering Kernel netlink command channel
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Registering gratuitous ARP shared channel
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Netlink reflector reports IP fe80::a00:27ff:fe3b:2360 added
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Registering Kernel netlink reflector
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Registering Kernel netlink command channel
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Configuration is using : 72628 Bytes
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Configuration is using : 7886 Bytes
Jan 16 20:19:06 proxy Keepalived_healthcheckers[25254]: Using LinkWatch kernel netlink reflector...
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: Using LinkWatch kernel netlink reflector...
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Entering BACKUP STATE
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Jan 16 20:19:06 proxy Keepalived_vrrp[25255]: VRRP_Script(chk_nginx) succeeded
Jan 16 20:19:07 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_1) Transition to MASTER STATE
Jan 16 20:19:08 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_1) Entering MASTER STATE
Jan 16 20:19:08 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_1) setting protocol VIPs.
Jan 16 20:19:08 proxy Keepalived_healthcheckers[25254]: Netlink reflector reports IP 172.16.31.88 added
Jan 16 20:19:08 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.88
Jan 16 20:19:09 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 172.16.31.88
Jan 16 20:19:10 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) forcing a new MASTER election
Jan 16 20:19:10 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) forcing a new MASTER election
Jan 16 20:19:11 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Transition to MASTER STATE
Jan 16 20:19:12 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Entering MASTER STATE
Jan 16 20:19:12 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) setting protocol VIPs.
Jan 16 20:19:12 proxy Keepalived_healthcheckers[25254]: Netlink reflector reports IP 172.16.31.188 added
#查看proxy2节点的日志，发现nginx服务检查失败，可能nginx服务停止了，我们去启动nginx服务后在查看日志：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 20:19:06 proxy2 Keepalived[7034]: Starting Keepalived v1.2.13 (10/15,2014)
Jan 16 20:19:06 proxy2 Keepalived[7036]: Starting Healthcheck child process, pid=7038
Jan 16 20:19:06 proxy2 Keepalived[7036]: Starting VRRP child process, pid=7039
Jan 16 20:19:06 proxy2 Keepalived_vrrp[7039]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 20:19:06 proxy2 Keepalived_vrrp[7039]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 20:19:06 proxy2 Keepalived_vrrp[7039]: Registering Kernel netlink reflector
Jan 16 20:19:06 proxy2 Keepalived_vrrp[7039]: Registering Kernel netlink command channel
Jan 16 20:19:06 proxy2 Keepalived_vrrp[7039]: Registering gratuitous ARP shared channel
Jan 16 20:19:07 proxy2 Keepalived_vrrp[7039]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Netlink reflector reports IP 172.16.31.53 added
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Netlink reflector reports IP fe80::a00:27ff:fe6e:bd28 added
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Registering Kernel netlink reflector
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Registering Kernel netlink command channel
Jan 16 20:19:07 proxy2 Keepalived_vrrp[7039]: Configuration is using : 72628 Bytes
Jan 16 20:19:07 proxy2 Keepalived_vrrp[7039]: Using LinkWatch kernel netlink reflector...
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Opening file '/etc/keepalived/keepalived.conf'.
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Configuration is using : 7886 Bytes
Jan 16 20:19:07 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 16 20:19:07 proxy2 Keepalived_vrrp[7039]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Jan 16 20:19:07 proxy2 Keepalived_healthcheckers[7038]: Using LinkWatch kernel netlink reflector...
Jan 16 20:19:07 proxy2 Keepalived_vrrp[7039]: VRRP_Script(chk_nginx) succeeded
Jan 16 20:19:08 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Transition to MASTER STATE
Jan 16 20:19:08 proxy2 Keepalived_vrrp[7039]: VRRP_Script(chk_nginx) failed
Jan 16 20:19:09 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Entering MASTER STATE
Jan 16 20:19:09 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) setting protocol VIPs.
Jan 16 20:19:09 proxy2 Keepalived_healthcheckers[7038]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 20:19:09 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 20:19:10 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 20:19:10 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Received higher prio advert
Jan 16 20:19:10 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Entering BACKUP STATE
Jan 16 20:19:10 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) removing protocol VIPs.
Jan 16 20:19:10 proxy2 Keepalived_healthcheckers[7038]: Netlink reflector reports IP 172.16.31.188 removed
在proxy2节点启动nginx服务
[root@proxy2 keepalived]# service nginx status
nginx is stopped
[root@proxy2 keepalived]# service nginx start
Starting nginx: [ OK ]
观察两个节点的日志记录：
proxy节点将属于proxy2节点的VIP返还了：
[root@proxy keepalived]# tail -f /var/log/messages
Jan 16 20:19:12 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 20:19:13 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 20:23:28 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Received higher prio advert
Jan 16 20:23:28 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) Entering BACKUP STATE
Jan 16 20:23:28 proxy Keepalived_vrrp[25255]: VRRP_Instance(VI_2) removing protocol VIPs.
Jan 16 20:23:28 proxy Keepalived_healthcheckers[25254]: Netlink reflector reports IP 172.16.31.188 removed
proxy2节点的VIP设置成功：
[root@proxy2 keepalived]# tail -f /var/log/messages
Jan 16 20:23:27 proxy2 Keepalived_vrrp[7039]: VRRP_Script(chk_nginx) succeeded
Jan 16 20:23:28 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) forcing a new MASTER election
Jan 16 20:23:28 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) forcing a new MASTER election
Jan 16 20:23:29 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Transition to MASTER STATE
Jan 16 20:23:30 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Entering MASTER STATE
Jan 16 20:23:30 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) setting protocol VIPs.
Jan 16 20:23:30 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 172.16.31.188
Jan 16 20:23:30 proxy2 Keepalived_healthcheckers[7038]: Netlink reflector reports IP 172.16.31.188 added
Jan 16 20:23:31 proxy2 Keepalived_vrrp[7039]: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 172.16.31.188
我们在DNS服务器中增加一个域名，对应的虚拟IP为172.16.31.88：
[root@proxy keepalived]# vim /var/named/stu31.com.zone
$TTL 600
$ORIGIN stu31.com.
@ IN SOA ns1.stu31.com. root.stu31.com. (
2014121801
1D
5M
1W
1H)
@ IN NS ns1.stu31.com.
ns1 IN A 172.16.31.52
www IN A 172.16.31.188
www1 IN A 172.16.31.88
重启named服务器后在客户端访问测试：
至此，nginx+keepalived的双主高可用负载均衡集群构建成功！
