负载均衡_集群方案_keepalive+nginx或keepalive+haproxy

2016-06-21 20:31

引言

Nginx是一个高性能的代理服务器,单台Nginx容易出现单点故障,使用keepalived可以实现Nginx的故障转移,保证了网站的高可用性

一、 使用Nginx+keepalived的两种方案

1、主从模式

使用一个VIP,前端有2台服务器,一主一从,正常情况下是主服务器提供服务只有当主服务器不能正常提供服务之后,从服务器才提供服务,此时总会有一台服务器是空闲状态。

2、双主模式

使用两个VIP,前段有2台服务器,互为主从,两台服务器同时工作,不存在资源浪费情况。同时在前段的DNS服务器对网站做多条A记录,实现了Nginx的负载均衡,当一台服务器故障时候,资源会转移到另一台服务器,继续提供服务,在大型的网站中多数都使用此种架构。在此使用主主模式配置Nginx+keepalived的高可用性。

二、准备实验环境

1、服务器IP地址规划

VIP:172.16.10.8

VIP:172.16.10.9

Keepalived1:172.16.10.1

Keepalived2:172.16.10.2

2、服务器操作系统

Keepalived1 :Centos 6.4 x86_64

Keepalived2 :Centos 6.4 x86_64

3、网络拓扑图

负载均衡_集群方案_keepalive+nginx或keepalive+haproxy0

4、修改主机名以及hosts文件keepalived1

####keepalived1 server############
sed -i 's@\(HOSTNAME=\).*@\1keepalived1@g'/etc/sysconfig/network
hostname keepalived1
[root@keepalived1 ~]# echo "172.16.10.1 keepalived1">> /etc/hosts
[root@keepalived1 ~]# echo "172.16.10.2 keepalived2">> /etc/hosts
[root@keepalived1 ~]# ssh-keygen -t rs
[root@keepalived1 ~]# ssh-copy-id -i .ssh/id_rsa.pub keepalived2
[root@keepalived1 ~]# scp /etc/hosts keepalived1:/etc/
####keepalived2 server############
sed -i 's@\(HOSTNAME=\).*@\1keepalived2@g'/etc/sysconfig/network
hostname keepalived2
[root@keepalived2 ~]# ssh-keygen -t rsa
[root@keepalived2 ~]# ssh-copy-id -i .ssh/id_rsa.pub keepalived1

三、编译安装Nginx

[root@keepalived1 ~]# yum install openssl-devel pcre-devel gcc -y
[root@keepalived1 ~]# tar xf nginx-1.4.2.tar.gz -C /usr/local/
[root@keepalived1 ~]# cd /usr/local/
[root@keepalived1 local]# groupadd -r nginx
[root@keepalived1 local]# useradd -r -g nginx nginx
[root@keepalived1 local]# cd nginx-1.4.2/
[root@keepalived1 nginx-1.4.2]# ./conf
conf/      configure
[root@keepalived1 nginx-1.4.2]# ./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
[root@keepalived1 nginx-1.4.2]# make && make install
[root@keepalived1 nginx-1.4.2]# vim /etc/init.d/nginx
#!/bin/sh
#
# nginx - this script starts and stops the nginx daemon
#
# chkconfig:   - 85 15
# description:  Nginx is an HTTP(S) server, HTTP(S) reverse \
#               proxy and IMAP/POP3 proxy server
# processname: nginx
# 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
[root@keepalived1 nginx-1.4.2]# chmod +x /etc/init.d/nginx
[root@keepalived1 nginx-1.4.2]# service nginx start

注意在此只上传了keepalived1的代码,keepalived2也需要同样的操作

1、修改默认网页以方便后期测试

###############keepalived1######################
[root@keepalived1 ~]# echo "<h1>keepalived1</h1>" > /usr/html/index.html
###############keepalived2######################
[root@keepalived2 ~]# echo "<h1>keepalived2</h1>" > /usr/html/index.html

四、 安装与配置keepalived

1、安装keepalived

###############keepalived1######################
[root@keepalived1 ~]# yum install keepalived -y
###############keepalived2######################
[root@keepalived2 ~]# yum install keepalived -y

2、修改配置文件

[root@keepalived1 keepalived]# grep -v "#" /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from Alexandre.Cassen@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
 vrrp_script chk_nginx {        #监控nginx脚本
    script "killall -0 nginx"   #监控nginx进程
    interval 1                  #监控间隔
    weight -2                   #优先级-2
}
vrrp_instance VI_1 {
    state MASTER                 #主server 
    interface eth0             
    virtual_router_id 80
      priority 100               #优先级
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.10.8            #定义vip
    }
    track_script {
    chk_nginx                 #跟踪脚本
}
    notify_master "/etc/keepalived/notify8.sh master"  #定义邮件通知
    notify_backup "/etc/keepalived/notify8.sh backup"
    notify_fault "/etc/keepalived/notify8.sh fault"
}
                                                                                                                                                            
vrrp_instance VI_2 {
    state BACKUP            #从server
    interface eth0
    virtual_router_id 81
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.10.9
    }
    track_script {
    chk_nginx
}
    notify_master "/etc/keepalived/notify9.sh master" #定义邮件通知
    notify_backup "/etc/keepalived/notify9.sh backup"
    notify_fault "/etc/keepalived/notify9.sh fault"
}
[root@keepalived1 keepalived]#

3、编辑邮件通知脚本(notify8.sh notify9.sh)

#####################notify8.sh##############
[root@keepalived1 keepalived]# cat notify8.sh
#!/bin/bash
# Author: xiaodong <xiaodong@foxmail.com>
# description: An example of notify script
#
vip=172.16.10.8
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
        exit 0
    ;;
    *)
        echo 'Usage: `basename $0` {master|backup|fault}'
        exit 1
    ;;
esac
####################notfiy9.sh#################
[root@keepalived1 keepalived]# cat notify9.sh
#!/bin/bash
# Author: xiaodong <xiaodong@foxmail.com>
# description: An example of notify script
#
vip=172.16.10.9
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
         exit 0
    ;;
    backup)
        notify backup
       exit 0
    ;;
    fault)
        notify fault
        exit 0
    ;;
    *)
        echo 'Usage: `basename $0` {master|backup|fault}'
        exit 1
    ;;
esac
[root@keepalived1 keepalived]# chmod +x notify8.sh
[root@keepalived1 keepalived]# chmod +x notify9.sh