nginx+keepalived实现双主负载均衡

双活模式需要定义两个vip，主备模式定义一个vip即可。

测试环境如下：

系统：Centos 6.4 64位

nginx服务器 no1：172.16.4.7 vip：172.16.4.55      版本：nginx-1.4.2.tar.gz

nginx服务器 no2：172.16.4.11 vip：172.16.4.56     版本：nginx-1.4.2.tar.gz

No1、no2双机互信

#vim /etc/hosts

172.16.4.7 no1.test.com no1

172.16.4.11 no2.test.com no2

No1:

#ssh-keygen -t rsa -P ‘’

#ssh-copy-id -i .ssh/id_rsa.pub ​​[e-mail]​​

No2:

#ssh-keygen -t rsa -P ‘’

#ssh-copy-id -i .ssh/id_rsa.pub ​​[e-mail]​​

还要确保两个节点时间同步

一、Nginx+keepalived 安装

1、安装编译所依赖的包pcre-devel openssl-devel

# yum -y install pcre-devel openssl-devel openssh-clients keepalived

2、解压并添加用户nginx，以nginx的身份运行服务

tar xf nginx-1.4.2.tar.gz -C /usr/local/
cd /usr/local/nginx-1.4.2
groupadd -r nginx
useradd -r -g nginx nginx

3、编译和安装

# ./configure \
    --prefix=/usr \ 
    --sbin-path=/usr/sbin/nginx \
    --conf-path=/etc/nginx/nginx.conf \
    --error-log-path=/var/log/nginx/error.log \--http-log-path=/var/log/nginx/access.log \
    --pid-path=/var/run/nginx/nginx.pid \
    --lock-path=/var/lock/nginx.lock \
    --user=nginx \
    --group=nginx \
    --with-http_ssl_module \
    --with-http_flv_module \
    --with-http_stub_status_module \
    --with-http_gzip_static_module \
    --http-client-body-temp-path=/var/tmp/nginx/client/ \
    --http-proxy-temp-path=/var/tmp/nginx/proxy/ \
    --http-fastcgi-temp-path=/var/tmp/nginx/fcgi/ \
    --http-uwsgi-temp-path=/var/tmp/nginx/uwsgi \
    --http-scgi-temp-path=/var/tmp/nginx/scgi \
    --with-pcre

编译过程中如果提示我们还需要依赖某个包时，我们要安装对应的devel包

# make && make install

4、为nginx提供SysV init脚本

脚本存放位置/etc/rc.d/init.d/nginx

​

#!/bin/sh
# chkconfig: - 85 15
# config: /etc/nginx/nginx.conf
# config: /etc/sysconfig/nginx
# pidfile: /var/run/nginx.pid
# Source function library.
. /etc/rc.d/init.d/functions
# Source networking configuration.
. /etc/sysconfig/network
# Check that networking is up.
[ "$NETWORKING" = "no" ] && exit 0
nginx="/usr/sbin/nginx"
prog=$(basename $nginx)
NGINX_CONF_FILE="/etc/nginx/nginx.conf"
[ -f /etc/sysconfig/nginx ] && . /etc/sysconfig/nginx
lockfile=/var/lock/subsys/nginx
make_dirs() {
# make required directories
user=`nginx -V 2>&1 | grep "configure arguments:" | sed 's/[^*]*--user=\([^ ]*\).*/\1/g' -`
options=`$nginx -V 2>&1 | grep 'configure arguments:'`
for opt in $options; do
if [ `echo $opt | grep '.*-temp-path'` ]; then
value=`echo $opt | cut -d "=" -f 2`
if [ ! -d "$value" ]; then
# echo "creating" $value
mkdir -p $value && chown -R $user $value
fi
fi
done
}
start() {
[ -x $nginx ] || exit 5
[ -f $NGINX_CONF_FILE ] || exit 6
make_dirs
echo -n $"Starting $prog: "
daemon $nginx -c $NGINX_CONF_FILE
retval=$?
echo
[ $retval -eq 0 ] && touch $lockfile
return $retval
}
stop() {
echo -n $"Stopping $prog: "
killproc $prog -QUIT
retval=$?
echo
[ $retval -eq 0 ] && rm -f $lockfile
return $retval
}
restart() {
configtest || return $?
stop
sleep 1
start
}
reload() {
configtest || return $?
echo -n $"Reloading $prog: "
killproc $nginx -HUP
RETVAL=$?
echo
}
force_reload() {
restart
}
configtest() {
$nginx -t -c $NGINX_CONF_FILE
}
rh_status() {
status $prog
}
rh_status_q() {
rh_status >/dev/null 2>&1
}
case "$1" in
start)
rh_status_q && exit 0
$1
;;
stop)
rh_status_q || exit 0
$1
;;
restart|configtest)
$1
;;
reload)
rh_status_q || exit 7
$1
;;
force-reload)
force_reload
;;
status)
rh_status
;;
condrestart|try-restart)
rh_status_q || exit 0
;;
*)
echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
exit 2
esac

而后为此脚本赋予执行权限：

chmod +x /etc/rc.d/init.d/nginx
chkconfig --add nginx
chkconfig nginx on
service nginx start

二、no1 配置

mkdir -p /web/htdocs
echo "172.16.4.7" > /web/htdocs/index.html
chmod -R 777  /web/

#vim /etc/nginx/nginx.conf

server {

listen 80;

server_name localhost;

location / {

root /web/htdocs;

index index.html index.htm;

}

}

service nginx reload     #重新加载服务
curl 172.16.4.7            #curl命令请求或在浏览器访问

三、no1的Keepalived配置

​

# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
  notification_email {
    root@localhost
  }
  notification_email_from keepadmin@localhost
  smtp_server 127.0.0.1
  smtp_connect_timeout 30
  router_id LVS_DEVEL
}
vrrp_script chk_nginx {
#script "killall -0 nginx" 
script "/etc/keepalived/check_nginx.sh"
interval 2
weight -2
}

vrrp_instance VI_1 {
  state MASTER
  interface eth0
  virtual_router_id 55
  priority 100
  advert_int 1
  nopreempt                 #主机服务正常后不争抢
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
    172.16.4.55
}
track_script {
chk_nginx
}
}
vrrp_instance VI_2 {
  state BACKUP
  interface eth0
  virtual_router_id 56
  priority 99
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
    172.16.4.56
}
track_script {
chk_nginx
}
}

cat  /etc/keepalived/check_nginx.sh
#!/bin/bash
A=`ps -C nginx --no-header |wc -l`
if [ $A -eq 0 ];then
      /usr/sbin/nginx
      sleep 2
      if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
      killall keepalived
      fi
fi

脚本说明：脚本会先检测nginx进程是否在，如果不在就启动nginx服务，过了2秒再次检测如果nginx没起来就结束keepalived服务，使vip飘移到另外一台主机上。

四、no2的nginx配置以及keepalived配置

可以将no1的配置发送到no2上

#scp /etc/keepalived/keepalived.conf no2:/etc/keepalived/

然后在其keepalived配置中修改下面选项：

vrrp_instance VI_1 {

state BACKUP

interface eth0

virtual_router_id 55

priority 99

advert_int 1

​nopreempt

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

172.16.4.55

}

track_script {

chk_nginx

}

}

vrrp_instance VI_2 {

state MASTER

interface eth0

virtual_router_id 56

priority100

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

172.16.4.56

}

track_script {

chk_nginx

}

}

五、测试

分别在2台nginx上重启启动nginx和keepalived服务，然后停掉其中一台的服务，查看资源能否转移到另一台nginx上,

查看方式：

#ip addr show

#ip a

查看no1：

​​​ ​​​

查看no2：

​​​ ​​​

将no1节点服务停掉，然后查看资源转移情况

​​​​

​​ ​​

再将no1的服务开启查看资源转移

​​​ ​​​

#tail -f /var/log/messages #实时查看，不会退出日志

或者在浏览器访问我们定义的vip查看，这里我们就不演示了