keepalived+nginx實現nginx的高可用
=================================
nginx的高可用
nginx實現後端realserver的負載均衡
==================================
實驗環境：
OS：Centos 6.4(redhat 6.4)
yum源:
1 2 3 4 5 6 7 8 9 10 11 | [centos]name=sohu-centosbaseurl=http://mirrors.sohu.com/centos/$releasever/os/$basearchgpgcheck=1enable=0gpgkey=http://mirrors.sohu.com/centos/RPM-GPG-KEY-CentOS-6[epel]name=sohu-epelbaseurl=http://mirrors.sohu.com/fedora-epel/$releasever/$basearch/enable=1gpgcheck=0 |
拓撲圖：
拓撲圖的規劃：
IP地址 | 軟件 | |
Master | 172.16.22.1(VIP：172.16.22.100) | keepalived+nginx |
Backup | 172.16.22.2(VIP：172.16.22.100) | keepalived+nginx |
apache1 | 172.16.22.3 | httpd |
apache2 | 172.16.22.4 | httpd |
此架構需考慮的問題
1）、Master沒掛，則Master佔有vip且nginx運行在Master上
2）、Master掛了，則backup搶佔vip且在backup上運行nginx服務
3）、如果master服務器上的nginx服務掛了，則vip資源轉移到backup服務器上
4）、檢測後端服務器的健康狀態
Master和Backup兩邊都開啓nginx服務，無論Master還是Backup，當其中的一個keepalived服務停止後，vip都會漂移到keepalived服務還在的節點上，
如果要想使nginx服務掛了，vip也漂移到另一個節點，則必須用腳本或者在配置文件裏面用shell命令來控制。
首先必須明確後端服務器的健康狀態檢測keepalived在這種架構上是無法檢測的，後端服務器的健康狀態檢測是有nginx來判斷的，但是nginx的檢測機制有一定的缺陷，後端服務器某一個宕機之後，nginx還是會分發請求給它，在一定的時間內後端服務響應不了，nginx則會發給另外一個服務器，然後當客戶的請求來了，nginx會一段時間內不會把請求分發給已經宕機的服務器，但是過一段時間後，nginx還是會把分發請求發給宕機的服務器上。
一、安裝keepalived+nginx
Master：
1、安裝keepalived和編譯安裝nginx
[root@jie1 ~]# yum -y install keepalived [root@jie1 ~]#tar xf nginx-1.4.2.tar.gz [root@jie1 ~]#yum -y groupinstall "Development tools" "Server Platform Development" [root@jie1 ~]#yum -y install pcre-devel [root@jie1 ~]# cd nginx-1.4.2 [root@jie1 nginx-1.4.2]# groupadd nginx [root@jie1 nginx-1.4.2]# useradd -r -g nginx nginx [root@jie1 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@jie1 nginx-1.4.2]# make && make install
2、提供nginx的system V服務腳本文件
[root@jie1 nginx-1.4.2]# vim /etc/rc.d/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.
[ "$NETWORKING"= "no"] && exit0
nginx="/usr/sbin/nginx"
prog=$(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=`$nginx -V 2>&1 | grep'configure arguments:'`
foropt in$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 ] || exit5
[ -f $NGINX_CONF_FILE ] || exit6
make_dirs
echo-n $"Starting $prog: "
daemon $nginx -c $NGINX_CONF_FILE
retval=$?
echo
[ $retval -eq0 ] && touch$lockfile
return$retval
}
stop() {
echo-n $"Stopping $prog: "
killproc $prog -QUIT
retval=$?
echo
[ $retval -eq0 ] && rm-f $lockfile
return$retval
}
restart() {
configtest || return$?
stop
sleep1
start
}
reload() {
configtest || return$?
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/null2>&1
}
case"$1"in
start)
rh_status_q && exit0
$1
;;
stop)
rh_status_q || exit0
$1
;;
restart|configtest)
$1
;;
reload)
rh_status_q || exit7
$1
;;
force-reload)
force_reload
;;
status)
rh_status
;;
condrestart|try-restart)
rh_status_q || exit0
;;
*)
echo$"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
exit2
esac
[root@jie1 nginx-1.4.2]# chmod +x /etc/rc.d/init.d/nginx
[root@jie1 nginx-1.4.2]# service nginx start
Starting nginx: [ OK ]
[root@jie1 nginx-1.4.2]# scp -p /etc/rc.d/init.d/nginx 172.16.22.2:/etc/rc.d/init.d #把nginx的服務腳本複製到backup上，-p是保持原有的權限3、修改配置文件
[root@jie1 ~]# cd /etc/keepalived/
[root@jie1 keepalived]# vim keepalived.conf
global_defs {
notification_email {
root@localhost
}
notification_email_from admin@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LTT
}
vrrp_script chk_nginx { #檢測nginx服務是否在運行有很多方式，比如進程，用腳本檢測等等
script "killall -0 nginx" #用shell命令檢查nginx服務是否存在
interval 1 #時間間隔爲1秒檢測一次
weight -2 #當nginx的服務不存在了，就把當前的權重-2
fall 2 #測試失敗的次數
rise 1 #測試成功的次數
}
vrrp_instance IN_1 {
state MASTER
interface eth0
virtual_router_id 22
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass aaaa
}
virtual_ipaddress {
172.16.22.100
}
track_script {
chk_nginx #引用上面的vrrp_script定義的腳本名稱
}
}
[root@jie1 keepalived]#scp keepalived.conf 172.16.22.2:/etc/keepalived #把配置文件copy到Backup服務器上，copy之前要保證Backup服務器上面已經安裝了keepalived4、開啓keepalived和nginx的服務
[root@jie1 keepalived]# service keepalived start Starting keepalived: [ OK ] [root@jie1 keepalived]# chkconfig --add keepalived [root@jie1 keepalived]# chkconfig keepalived on [root@jie1 ~]# service nginx start Starting nginx: [ OK ] [root@jie1 ~]# chkconfig --add nginx [root@jie1 ~]# chkconfig nginx on
Backup：
1、安裝keepalived和編譯安裝nginx
[root@jie2 ~]# yum -y install keepalived [root@jie2 ~]#tar xf nginx-1.4.2.tar.gz [root@jie2 ~]#yum -y groupinstall "Development tools" "Server Platform Development" [root@jie2 ~]#yum -y install pcre-devel [root@jie2 ~]# cd nginx-1.4.2 [root@jie2 nginx-1.4.2]# groupadd nginx [root@jie2 nginx-1.4.2]# useradd -r -g nginx nginx [root@jie2 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@jie2 nginx-1.4.2]# make && make install
2、之前 已經從Master複製了nginx的system V服務腳本文件，啓動nginx服務
[root@jie2 ~]# service nginx start Starting nginx: [ OK ] [root@jie2 ~]# chkconfig --add nginx [root@jie2 ~]# chkconfig nginx on
3、修改配置文件
[root@jie2 ~]# cd /etc/keepalived/ [root@jie2 keepalived]# vim keepalived.conf #此配置文件是從Master服務器上copy過來，只需小小改動 state BACKUP #把這裏原先的MASTER改成BACKUP priority 99 #把這裏原先的100改成99
4、開啓服務
[root@jie2 keepalived]# service keepalived start Starting keepalived: [ OK ] [root@jie2 keepalived]# chkconfig --add keepalived [root@jie2 keepalived]# chkconfig keepalived on
apache1：
1、安裝(博主這裏用rpm包安裝，各位朋友可以用源碼編譯安裝)
[root@jie3 ~]# yum -y install httpd
2、建立測試網頁文件
[root@jie3 ~]# cd /var/www/html/ [root@jie3 html]# cat index.html #建一個測試網頁 <h1>this is apache1</h1>
3、開啓服務
[root@jie3 html]# service httpd start Starting httpd: [ OK ] [root@jie3 html]# chkconfig --add httpd [root@jie3 html]# chkconfig httpd on
apache2：
1、安裝(博主這裏用rpm包安裝，各位朋友可以用源碼編譯安裝)
[root@jie4 ~]# yum -y install httpd
2、建立測試網頁文件
[root@jie4 ~]# cd /var/www/html/ [root@jie4 html]# cat index.html #建一個測試網頁 <h1>this is apache2</h1>
3、開啓服務
[root@jie4 html]# service httpd start Starting httpd: [ OK ] [root@jie4 html]# chkconfig --add httpd [root@jie4 html]# chkconfig httpd on
此致所有安裝已經完成。
二、nginx實現後端realserver的負載均衡，由於兩邊的配置文件必須保持一致，所以在Master配置完後直接copy到Backup上
Master：
[root@jie1 ~]# cd /etc/nginx/
[root@jie1 nginx]# grep -v "#" nginx.conf | grep -v "^$"
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
upstream apacheweb { #定義負載均衡的模塊
server 172.16.22.3:80 max_fails=3 fail_timeout=2s;
server 172.16.22.4:80 max_fails=3 fail_timeout=2s;
}
server {
listen 80;
server_name localhost;
location / {
root html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
location ~ \.(html|htm|gif|jpg|jpeg|bmp|png|ico|txt|js|css)$ {
root /var/www/html; #此處定義後端服務器網頁存放路徑
proxy_pass http://apacheweb;
}
}
}
[root@jie1 nginx]# scp nginx.conf 172.16.22.2:/etc/nginx兩邊分別重啓服務
[root@jie2 nginx]# service nginx restart nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful Stopping nginx: [ OK ] Starting nginx: [ OK ] [root@jie2 nginx]# service nginx restart nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful Stopping nginx: [ OK ] Starting nginx: [ OK ]
驗證負載均衡：
本博客只是簡單的用nginx做了方向代理和靜態頁面的負載均衡，keepalived+nginx實現高可用的nginx的動靜分離，讀寫分離，後續會持續更新