keepalived + nginx
centos6.5-x86_64nginx-1.4.5
keepalived-1.2.5
master: 192.168.1.126
slave : 192.168.1.128
vip : 192.168.1.130
一、软件下载：
wget http://www.keepalived.org/software/keepalived-1.2.5.tar.gz
http://nginx.org/en/download.html
二、安装nginx
参考http://dodowolf.blog.51cto.com/793581/1596684
三、keepalived (以下为源码安装 或 #yum-y install keepalived)
1.安装依赖包
#yum -y install gcc gcc+ gcc-c++ popt openssl openssl-devellibnllibnl-devel
#yum -y install kernel kernel-devel
当前kernel代码建立连接 ln -s /usr/src/kerners/2.6....../ /usr/src/linux
2.安装keepalived
# tar -zxvf keepalived-1.2.5.tar.gz
# cd keepalived-1.2.5
# ./configure
# make
# make install
3.cp相应文件到系统目录
#cp /usr/local/sbin/keepalived /usr/sbin/
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/
#cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
#cp -r /usr/local/etc/keepalived/ /etc/
4.修改配置文件内容
/etc/keepalived/keepalived.conf
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
! Configuration File for keepalived
global_defs {
# notification_email {
# root@localhost
# }
# notification_email_from admin@localhost
# smtp_server localhost
# smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER #BACKUP
interface eth0
virtual_router_id 51
priority 100 #BACKUP 可设置为 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_interface {
eth0
}
virtual_ipaddress {
192.168.1.130
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault"/etc/keepalived/notify.sh fault"
}
#vi /etc/keepalived/notify.sh
#!/bin/bash
# time: 2015-1-5
# description: An example of notify script
#
vip=192.168.1.130
contact='XXX@163.com'
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 restart
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
四、Tell kernel to allow binding non-local IP into the hosts and apply the changes:
$ echo "net.ipv4.ip_nonlocal_bind = 1" >> /etc/sysctl.conf
$ sysctl -p
五、测试
1.master、slave分别启动nginx\keepalived
# /usr/local/nginx/sbin/nginx
# servicekeepalivedstart
2.测试
浏览器分别访问master,slave 测试是否正常
访问vip 可以看到显示的是master
在master上执行# servicekeepalived stop
访问vip显示slave
可以通过 /var/log/messages 查看切换日志
注意：1.以上是keepalived挂掉的情况下才切换到slave,如果nginx挂掉 不会切换，无法访问；所以做下以下设置
2.service network restart 一定要在keepalived停止的时候才执行，不要然后keepalived不会正常运行
六、应用层（web）的双机热备（比如nginx进程被意外kill、web端口不通）
1.主要是利用keepalived的track_script检测脚本的原理实现的
2.配置文件的修改
/etc/keepalived/keepalived.conf
~~~~~~~~~~~~~~~~~~~~~~~
! Configuration File for keepalived
global_defs {
# notification_email {
# root@localhost
# }
# notification_email_from admin@localhost
# smtp_server localhost
# smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx_down {
script "ps -C nginx --no-header 2>&- 1>&- && exit 0 || exit 1"
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER #BACKUP
interface eth0
virtual_router_id 51
priority 100 #BACKUP可设置为99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_interface {
eth0
}
track_script {
chk_nginx_down
}
virtual_ipaddress {
192.168.1.130
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault"/etc/keepalived/notify.sh fault"
}
七、以下介绍如何设置 外部邮箱发送邮件通知：
修改/etc/mail.rc
vi /etc/mail.rc
set from=mail@163.com
smtp=smtp.163.com
set smtp-auth-user=username
smtp-auth-password=password
smtp-auth=login
说明：
from是发送的邮件地址
smtp是发生的外部smtp服务器的地址
smtp-auth-user是外部smtp服务器认证的用户名
smtp-auth-password是外部smtp服务器认证的用户密码
smtp-auth是邮件认证的方式
配置成功后，就可以使用了
可以发送一封邮件测试一下：
mail -s "test" user@sohu.com
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