Nginx +keepalived 实现高可用和负载均衡
一、软件安装
1、安装nginx参考nginx 安装
2、安装keepalived 参考keepalived+lvs 的安装
这里提供两个经过我打包的rpm包
1、nginx 0.7.64下载
2、keepalived 1.1.20下载二、拓扑结构
http://life.mkrss.com/wp-content/uploads/2010/06/keepalived.jpg二、实现负载均衡和高可用的说明
1、当用户访问test.woyo.com 时，通过DNS 轮循机制，用户的请求会分别分发到两个keepalived 为master 的服务器上。 实现负载均衡的功能2、keepalived通过发送和接收组播包中的同一个virtual_router_id 的中的成员的存活，来确定对方的不可用，一旦检测到对方的不可用，即会切换他的备份角色为主，即：当真实机192.168.200.143上的keepalived 检测到 真实机192.168.200.144上的keepalived 不可用时，143上对 192.168.200.144的VIP 156的backup 会变为master3、keepalived 只能实现针对网络层的一个高可用，即 一台装有keepalived的进程检测不到另一台装有keepalived 的存活是，才会发生切换。4、针对应用层的一个检测keepalived 需要通过vrrp_scripts 来实现三、看如配置文件样例
1、关建点
1.互为主备关系的两台机器的vrrp_instance VI_1 里面的 virtual_router_id 52必需相同1、 143上的keepalived.conf# Configuration File for keepalived
# vrrp master master
global_defs {
notification_email {
root@mkrss.com
}
notification_email_from root@mkrss.com
smtp_server localhost
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx {
script "/tmp/check.sh"
interval 2
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_nginx 10
}
virtual_ipaddress {
192.168.200.145
}
}
vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 53
priority 80
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.200.146
}
}2、 144上的keepalived.conf# Configuration File for keepalived
# vrrp master master
global_defs {
notification_email {
root@mkrss.com
}
notification_email_from root@mkrss.com
smtp_server localhost
smtp_connect_timeout 30
router_id LVS_DEVEL2
}
#vrrp_script chk_nginx {
# script "/tmp/check.sh"
# interval 2
# weight 2
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 52
priority 80
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
# track_script {
# chk_nginx
# }
virtual_ipaddress {
192.168.200.145
}
}
vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 53
priority 180
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.200.146
}
}三、脚本#!/bin/sh
A=`ps -C nginx --no-header |wc -l`
if [ $A -eq 0 ]
then
/usr/local/nginx/sbin/nginx
sleep 1
if [ `ps -C nginx --no-header |wc -l` -eq 0 ]
then
killall keepalived
fi
fi四、测试方法1、分别在两台机器上写测试文件两台机器创建测试文件echo " php server a " > /usr/local/nginx/html/index.php
echo " php server b " > /usr/local/nginx/html/index.php 2、分两在两台机器上启动nginx 和keepalived Server nginx restart
Server keepalived restart3、 分别在两台机器上tail –f/var/log/messagesJun 13 17:19:35 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE
Jun 13 17:19:35 rs_200_143 Keepalived_vrrp: VRRP sockpool:
Jun 13 17:19:36 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_2) Transition to MASTER STATE
Jun 13 17:19:37 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_2) Entering MASTER STATE
Jun 13 17:20:40 rs_200_142 Keepalived_vrrp: VRRP_Instance(VI_2) Entering BACKUP STATE
Jun 13 17:20:40 rs_200_142 Keepalived_vrrp: VRRP sockpool:
Jun 13 17:20:41 rs_200_142 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Jun 13 17:20:42 rs_200_142 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Jun 13 17:20:42 rs_200_142 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.4、在一台机器上跑下面的语句for num in {1..10000} ;do curl http://192.168.200.145; echo ;done
php server a
php server a
php server a在143上执行server nginx stop
我们会看到如下curl: (7) couldn't connect to host
curl: (7) couldn't connect to host
约9个
php server b
php server b
php server b同时在143上也会看到如下日志的滚动 un 13 17:19:37 rs_200_143 avahi-daemon: Registering new address record for 192.168.200.146 on eth0.
Jun 13 17:19:42 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_2) Sending gratuitous ARPs on eth0 for 192.168.200.146
Ju 13 17:28:19 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Jun 13 17:28:20 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Jun 13 17:28:20 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Jun 13 17:28:20 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.200.145
Jun 13 17:28:20 rs_200_143 avahi-daemon: Registering new address record for 192.168.200.145 on eth0.
Jun 13 17:28:25 rs_200_143 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.200.145
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