标签：nginx keepalived
keepalived的工作原理基于三个层面，分别时IP层，TCP层和应用层
IP
层：keepalived会定期向服务器集群中的服务器发送一个类似于ping程序的ICMP数据包。通俗理解就是我keepalived来ping你服
务器，我要是ping通了，那我知道你还活着，咱们可以继续合作，如果不幸发现你挂了，那就得把这台服务器踢了。该层就是确保服务器ip地址有效，一次来
判断这台服务器可否继续在岗谋职。
TCP层：这一层和IP层类似，只不过IP层检查的是IP，该层检查TCP端口。keepalived在IP层
且报你服务器的IP有效，然后继续看你的TCP端口，比如说你是web
server，那你的80端口就应该开启，如果keepalived发现你的80端口没有启动。那么它就会认为你已经挂掉，然后剔除。
应用层：这一层就是具体的工作程序了，keepalived是个恪尽职守的检察官，应用层的程序与用户的设定息息相关，keepalived则通过检查服务器的运行是否和用户设定一致，如果不一致，keepalived就会宣判这台服务器牺牲。
主机：172.25.44.3 server3
备机：172.25.44.4 server4
[root@server3 ～]# vim /etc/sysconfig/network-scripts/ifcfg-eth0:0DEVICE=eth0:0TYPE=EthernetONBOOT=yesBOOTPROTO=staticDNS1=172.25.44.44IPADDR=172.25.44.100NETMASK=255.255.255.0GETWAY=172.25.44.44[root@server3 ～]# /etc/init.d/network restart[root@server3 ～]# ifconfigeth0 Link encap:Ethernet HWaddr 52:54:00:48:60:3E inet addr:172.25.44.4 Bcast:172.25.44.255 Mask:255.255.255.0 inet6 addr: fe80::5054:ff:fe48:603e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11926 errors:0 dropped:0 overruns:0 frame:0 TX packets:6533 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:25662550 (24.4 MiB) TX bytes:876645 (856.0 KiB) eth0:0 Link encap:Ethernet HWaddr 52:54:00:48:60:3E inet addr:172.25.44.100 Bcast:172.25.44.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:36283 errors:0 dropped:0 overruns:0 frame:0 TX packets:36283 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1982812 (1.8 MiB) TX bytes:1982812 (1.8 MiB)
安装包：nginx-1.10.3.tar.gz
解压安装包：tar zxf nginx-1.10.3.tar.gz
[root@server3 software]# cd nginx-1.10.3 —prefix=/usr/local/lnmp/nignx [root@server3 nginx-1.10.3]# ./configure [root@server3 nginx-1.10.3]# make [root@server3 nginx-1.10.3]# make install [root@server3 nginx-1.10.3]# ln -s /usr/local/lnmp/nginx/sbin/nginx /usr/local/sbin/ #创建nginx的软链接
[root@server3 nginx-1.10.3]# cd /usr/local/lnmp/nginx/conf[root@server3 conf]# vim nginx.conf/#访问8088端口是的发布目录为/var/www/html，而nginx的默认发布目录还是/usr/local/lnmp/nginx/html
server { listen 8088；#监听8088端口 server_name localhost;
location / {
root /var/www/html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/local/lnmp/nginx/html;
}
}
[root@server3 conf]# cd /var/www/html[root@server3 html]# vim index.html
<html>
<head>
<title>Welcome to nginx!</title>
</head>
<body bgcolor="white" text="black">
<center><h1>Welcome to nginx! 172.25.44.3</h1></center>
</body>
</html>
[root@server3 html]# nginx安装包：keepalived-1.2.2.tar.gz
[root@server3 software]# wget http://www.keepalived.org/software/keepalived-1.2.2.tar.gz [root@server3 software]# tar zxf keepalived-1.2.2.tar.gz [root@server3 software]# cd keepalived-1.2.2 [root@server3 keepalived-1.2.2]# ./configure [root@server3 keepalived-1.2.2]# make [root@server3 keepalived-1.2.2]# make install [root@server3 keepalived-1.2.2]# cp /usr/local/sbin/keepalived /usr/sbin/ [root@server3 keepalived-1.2.2]# cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/ [root@server3 keepalived-1.2.2]# cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/ [root@server3 keepalived-1.2.2]# cp -r /usr/local/etc/keepalived/ /etc/
[root@server3 keepalived-1.2.2]# vim /var/www/html/index.html
global_defs {
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script “</dev/tcp/127.0.0.1/8088”
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.44.100
}
track_script {
chk_http_port
}[root@server3 keepalived-1.2.2]# /etc/init.d/keepalived start
备机次同步主机的操作步骤：keepalived的配置文件中，主机的state为MASTER，备机的state为BACKUP，备机的priority要小于主机
[root@server3 software]# /etc/init.d/keepalived stop Stopping keepalived: [ OK ]
[root@server4 conf]# ip a 1: lo: mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 52:54:00:48:60:3e brd ff:ff:ff:ff:ff:ff inet 172.25.44.4/24 brd 172.25.44.255 scope global eth0 inet 172.25.254.104/24 brd 172.25.254.255 scope global eth0 inet 172.25.44.100/32 scope global eth0 inet 172.25.44.100/24 brd 172.25.44.255 scope global secondary eth0:0 inet6 fe80::5054:ff:fe48:603e/64 scope link valid_lft forever preferred_lft forever
[root@server3 software]# /etc/init.d/keepalived start Starting keepalived: [ OK ]
[root@server3 software]# ip a 1: lo: mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 52:54:00:b4:14:0d brd ff:ff:ff:ff:ff:ff inet 172.25.44.3/24 brd 172.25.44.255 scope global eth0 inet 172.25.254.103/24 brd 172.25.254.255 scope global eth0 inet 172.25.44.100/32 scope global eth0 inet6 fe80::5054:ff:feb4:140d/64 scope link valid_lft forever preferred_lft forever
[root@server3 software]# killall nginx
问题补充：在备机keepalived的配合配置文件中，如果补修改state的情况下实验也是可以成功的，我觉得应该时两个机子通过priority优先级竞争。
本文出自 “12449513” 博客，请务必保留此出处http://12459513.blog.51cto.com/12449513/1930314
标签：nginx keepalived
原文地址：http://12459513.blog.51cto.com/12449513/1930314
