Centos6下nginx+keepalived构建高可用web集群

1）拓扑描述：



2) nginx的安装准备
pcre:兼容的正则表达式，nginx也要支持伪静态

# yum -y install pcre pcre-devel
# yum -y install openssl*
# mkdir -p /application/nginx1.6.2
# ln -s /application/nginx1.6.2 /application/nginx

3) 安装nginx

# cd /usr/local/src
# tar xf nginx-1.6.2.tar.gz
# cd nginx-1.6.2
# useradd nginx -s /sbin/nologin -M
# ./configure --user=nginx --group=nginx --prefix=/application/nginx1.6.2 --with-http_stub_status_module --with-http_ssl_module
# echo $?
0
# make && make install

4) 启动nginx

检查语法：
# /application/nginx1.6.2/sbin/nginx -t
nginx: the configuration file /application/nginx1.6.2/conf/nginx.conf syntax is ok
nginx: configuration file /application/nginx1.6.2/conf/nginx.conf test is successful
启动nginx：
# /application/nginx/sbin/nginx
查看端口号：
# lsof -i :80
COMMAND   PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
nginx   14603  root    6u  IPv4  29397      0t0  TCP *:http (LISTEN)
nginx   14604 nginx    6u  IPv4  29397      0t0  TCP *:http (LISTEN)
# netstat -tunlp | grep nginx
tcp        0      0 0.0.0.0:80                  0.0.0.0:*                   LISTEN      14603/nginx
测试网页页面：
# curl -I localhost
HTTP/1.1 200 OK
Server: nginx/1.6.2
Date: Tue, 20 Sep 2016 02:17:20 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 20 Sep 2016 02:11:05 GMT
Connection: keep-alive
ETag: "57e09ab9-264"
Accept-Ranges: bytes

5）配置nginx启动脚本

# vim /etc/init.d/nginx
#!/bin/sh
# chkconfig: 2345 85 15
# description:Nginx Server
# nginx的安装目录
NGINX_HOME=/application/nginx
# nginx的命令
NGINX_SBIN=$NGINX_HOME/sbin/nginx
# nginx的配置文件
NGINX_CONF=$NGINX_HOME/conf/nginx.conf
# nginx的pid
NGINX_PID=$NGINX_HOME/logs/nginx.pid

NGINX_NAME="Nginx"

. /etc/rc.d/init.d/functions

if [ ! -f $NGINX_SBIN ]
then
echo "$NGINX_NAME startup: $NGINX_SBIN not exists! "
exit
fi

start() {
$NGINX_SBIN -c $NGINX_CONF
ret=$?
if [ $ret -eq 0 ]; then
action $"Starting $NGINX_NAME: " /bin/true
else
action $"Starting $NGINX_NAME: " /bin/false
fi
}

stop() {
kill `cat $NGINX_PID`
ret=$?
if [ $ret -eq 0 ]; then
action $"Stopping $NGINX_NAME: " /bin/true
else
action $"Stopping $NGINX_NAME: " /bin/false
fi
}

restart() {
stop
start
}

check() {
$NGINX_SBIN -c $NGINX_CONF -t
}

reload() {
kill -HUP `cat $NGINX_PID` && echo "reload success!"
}

relog() {
kill -USR1 `cat $NGINX_PID` && echo "relog success!"
}

case "$1" in
start)
start
;;
stop)
stop
;;
restart)
restart
;;
check|chk)
check
;;
status)
status -p $NGINX_PID
;;
reload)
reload
;;
relog)
relog
;;
*)
echo $"Usage: $0 {start|stop|restart|reload|status|check|relog}"
exit 1
esac
# chmod +x /etc/init.d/nginx
# /etc/init.d/nginx start
# chkconfig --add nginx
# chkconfig nginx on

6) 配置nginx的upstream功能（两台负载均衡器上做相同的配置）

# egrep -v '#' /application/nginx/conf/nginx.conf|grep -v '^$'
worker_processes  1;
events {
worker_connections  1024;
}
http {
include       mime.types;
default_type  application/octet-stream;
include extra/upstream01.conf;
sendfile        on;
keepalive_timeout  65;
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;
}
}
}
说明：注意include extra/upstream01.conf这个文件，是引用此文件(两台负载均衡器上做系统的nginx配置)
# mkdir -p /application/nginx/conf/extra/
# vim /application/nginx/conf/extra/upstream01.conf
upstream nginx.wanwan.com {
server 10.10.10.128:80 weight=5;
server 10.10.10.132:80 weight=5;
}
server {
listen80;
server_namenginx.wanwan.com;
location / {
proxy_pass http://nginx.wanwan.com; }
}
# /etc/init.d/nginx restart
Stopping Nginx:                                            [确定]
Starting Nginx:                                            [确定]

7）keepalived的安装

# cd /usr/local/src
# wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz # ln -s /usr/src/kernels/2.6.32-573.el6.x86_64/ /usr/src/linux
# ls -l /usr/src
总用量 244
drwxr-xr-x. 2 root root   4096 9月  23 2011 debug
-rw-r--r--  1 root root 241437 1月  28 2014 keepalived-1.1.19.tar.gz
drwxr-xr-x. 3 root root   4096 7月   5 23:49 kernels
lrwxrwxrwx  1 root root     39 8月  31 08:49 linux -> /usr/src/kernels/2.6.32-573.el6.x86_64/
# tar xf keepalived-1.1.19.tar.gz
# cd keepalived-1.1.19
# ./configure
# make && make install
# cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/
# cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
# mkdir -p /etc/keepalived
# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
# cp /usr/local/sbin/keepalived /usr/sbin/
# /etc/init.d/keepalived start
正在启动 keepalived：                                      [确定]
# ps -ef | grep keepalived
root      18750      1  0 22:55 ?        00:00:00 keepalived -D
root      18752  18750  0 22:55 ?        00:00:00 keepalived -D
root      18753  18750  0 22:55 ?        00:00:00 keepalived -D
root      18755  18664  0 22:55 pts/0    00:00:00 grep keepalived
keepalived-master的配置文件/etc/keepalived/keepalived.conf
[root@nginx01 extra]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
314324506@qq.com
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server smtp.qq.com
smtp_connect_timeout 30
router_id nginx_7
}
vrrp_instance VI_231 {
state MASTER
interface eth0
virtual_router_id 231
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.10.10.231/24
}
}
}
keepalived-slave的配置文件/etc/keepalived/keepalived.conf
[root@nginx02 ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
314324506@qq.com
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server smtp.qq.com
smtp_connect_timeout 30
router_id nginx_7
}
vrrp_instance VI_231 {
state BACKUP
interface eth0
virtual_router_id 231
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.10.10.231/24
}
}
}

8) 测试keepalived的功能（VIP为10.10.10.231)

[root@nginx01 extra]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:d7:3e:f8 brd ff:ff:ff:ff:ff:ff
inet 10.10.10.131/24 brd 10.10.10.255 scope global eth0
inet 10.10.10.231/24 scope global secondary eth0
inet6 fe80::20c:29ff:fed7:3ef8/64 scope link
valid_lft forever preferred_lft forever
[root@nginx02 ~]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:71:33:eb brd ff:ff:ff:ff:ff:ff
inet 10.10.10.135/24 brd 10.10.10.255 scope global eth0
inet6 fe80::20c:29ff:fe71:33eb/64 scope link
valid_lft forever preferred_lft forever

关闭主负载均衡上的keepalived功能
[root@nginx01 extra]# /etc/init.d/keepalived stop
停止 keepalived：                                          [确定]
[root@nginx01 extra]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:d7:3e:f8 brd ff:ff:ff:ff:ff:ff
inet 10.10.10.131/24 brd 10.10.10.255 scope global eth0
inet6 fe80::20c:29ff:fed7:3ef8/64 scope link
valid_lft forever preferred_lft forever

[root@nginx02 ~]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:71:33:eb brd ff:ff:ff:ff:ff:ff
inet 10.10.10.135/24 brd 10.10.10.255 scope global eth0
inet 10.10.10.231/24 scope global secondary eth0
inet6 fe80::20c:29ff:fe71:33eb/64 scope link
valid_lft forever preferred_lft forever
由上，我们可以知道vip很快就进行了切换，那么我们恢复主负载均衡器上的keepalived功能：
[root@nginx01 extra]# /etc/init.d/keepalived start
正在启动 keepalived：                                      [确定]
[root@nginx01 extra]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:d7:3e:f8 brd ff:ff:ff:ff:ff:ff
inet 10.10.10.131/24 brd 10.10.10.255 scope global eth0
inet 10.10.10.231/24 scope global secondary eth0
inet6 fe80::20c:29ff:fed7:3ef8/64 scope link
valid_lft forever preferred_lft forever
[root@nginx02 ~]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:71:33:eb brd ff:ff:ff:ff:ff:ff
inet 10.10.10.135/24 brd 10.10.10.255 scope global eth0
inet6 fe80::20c:29ff:fe71:33eb/64 scope link
valid_lft forever preferred_lft forever
由上，我们发现当主负载均衡器恢复后，vip很快就切换过来了（因为主负载均衡器上的优先级更高）

9）测试nginx的反向代理功能

[root@web01 ~]# curl 10.10.10.128
mysql successful by oldboy !
[root@web01 ~]# curl 10.10.10.132
this is web02's website

然后我们在客户端打开nginx.wanwan.com



按F5刷新：

[root@nginx01 extra]# /etc/init.d/nginx stop
Stopping Nginx:                                            [确定]
[root@nginx01 extra]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:d7:3e:f8 brd ff:ff:ff:ff:ff:ff
inet 10.10.10.131/24 brd 10.10.10.255 scope global eth0
inet 10.10.10.231/24 scope global secondary eth0
inet6 fe80::20c:29ff:fed7:3ef8/64 scope link
valid_lft forever preferred_lft forever
[root@nginx01 extra]# /etc/init.d/keepalived stop
停止 keepalived：

由上可知，后端网页仍旧正常。

10）注意事项
a、注意关闭负载均衡器以及web后端服务器的iptables以及selinux功能

b、两台负载均衡器上关于nginx配置是一致的，keepalived有不同的优先级