nginx+keepalived高可用性負載均衡

一、前言

nginx進程基于于Master+Slave(worker)多進程模型，自 身具有非常穩定的子進程管理功能。在Master進程分配模式下，Master進程永遠不進行業務處理，只是進行任務分發，從而達到Master進程的存 活高可靠性，Slave(worker)進程所有的業務信號都 由主進程發出，Slave(worker)進程所有的超時任務都會被Master中止，屬于非阻塞式任務模型。

Keepalived是Linux下面實現VRRP 備份路由的高可靠性運行件。基于Keepalived設計的服務模式能夠真正做到主服務器和備份服務器故障時IP瞬間無縫交接。二者結合，可以構架出比較穩定的軟件lb方案。

二、nginx+keepalived架構實戰

采用兩臺服務器做nginx主備，后端采用兩個realserver（可以隨意擴展），數據庫采用mysql主從（這里就不說主從的配置了！）

1、?架構圖如下：

Server?	ip
nginx master?	192.168.1.108
nginx backup	192.168.1.110
vip	192.168.1.100
real server1	192.168.1.105
real server2	192.168.1.103

2、?安裝配置

（1）、安裝keepalived（在nginx的mater和backup都安裝）

wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz
tar zxvf keepalived-1.1.19.tar.gz
cd keepalived-1.1.19
./configure --prefix=/usr/local/keepalived
make
make install
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
mkdir /etc/keepalived
cd /etc/keepalived/

配置nginx master的keepalived配置文件

[root@zhang1 keepalived]# cat /etc/keepalived/keepalived.conf

bal_defs {

notification_email {

jimo291@gmail.com

}

notification_email_from jimo291@gmail.com

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id test1

}

vrrp_instance VI_1 {

state MASTER

interface eth0

virtual_router_id 51

priority 100

advert_int 1

smtp_alert

authentication {

auth_type PASS

auth_pass 123

}

virtual_ipaddress {

192.168.1.100

}

}

配置nginx backup的keepalived配置文件

[root@zhang1 keepalived]# cat /etc/keepalived/keepalived.conf

bal_defs {

notification_email {

jimo291@gmail.com

}

notification_email_from jimo291@gmail.com

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id test2

}

vrrp_instance VI_1 {

state BACKUP

interface eth0

virtual_router_id 51

priority 80

advert_int 1

smtp_alert

authentication {

auth_type PASS

auth_pass 123

}

virtual_ipaddress {

192.168.1.100

}

}

啟動keepalived！，查看虛擬IP是否綁定！

[root@zhang1 ~]# /etc/rc.d/init.d/keepalived start

Starting keepalived:?????????????????????????????????????? [?OK?]

[root@zhang1 ~]# ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue

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 qlen 1000

link/ether 00:0c:29:65:b4:ed brd ff:ff:ff:ff:ff:ff

inet 192.168.1.108/24 brd 192.168.1.255 scope global eth0

inet 192.168.1.100/32 scope global eth0

inet6 fe80::20c:29ff:fe65:b4ed/64 scope link

valid_lft forever preferred_lft forever

3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast qlen 1000

link/ether 00:0c:29:65:b4:f7 brd ff:ff:ff:ff:ff:ff

4: sit0: <NOARP> mtu 1480 qdisc noop

link/sit 0.0.0.0 brd 0.0.0.0

紅色部分顯示IP已經加載過來了！

3、?nginx的安裝和配置

1、創建供Nginx使用的組和帳號：
/usr/sbin/groupadd www -g 48
/usr/sbin/useradd -u 48 -g www www

2、編譯安裝rewrite模塊支持包
wget ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-7.7.tar.gz
tar zxvf pcre-7.7.tar.gz
cd pcre-7.7/
./configure
make && make install
cd ../

3、編譯安裝Nginx
wget http://sysoev.ru/nginx/nginx-0.7.64.tar.gz
tar zxvf nginx-0.7.64.tar.gz
cd nginx-0.7.64/
./configure --user=www --group=www --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_realip_module --with-http_flv_module
make && make install
cd ../

4、備份默認nginx.conf配置文件
mv /usr/local/nginx/conf/nginx.conf? /usr/local/nginx/conf/nginx.old

5、配置nginx(兩個nginx配置一樣！)

[root@linux4 keepalived]# cat /usr/local/nginx/conf/nginx.conf

userwww???? www;

worker_processes 8;

pid/var/run/nginx.pid;

worker_rlimit_nofile 51200;

events

{

use epoll;

worker_connections????? 5120;

}

http

{

include?????????? mime.types;

default_type?application/octet-stream;

charset?gb2312;

server_names_hash_bucket_size 128;

client_header_buffer_size 32k;

large_client_header_buffers 4 32k;

sendfile on;

tcp_nopush???????? on;

keepalive_timeout 60;

tcp_nodelay on;

gzip on;

gzip_min_length?1k;

gzip_buffers???????? 4 16k;

gzip_http_version 1.0;

gzip_comp_level 2;

gzip_types?????????? text/plain application/x-javascript text/css application/xml;

gzip_vary on;

upstream srtweb {

server?192.168.1.105:80;

server?192.168.1.103:80;

}

server {

listen 80;

server_name www.carl.com;

location /{

proxy_pass????? http://srtweb;

proxy_set_header Host?? $host;

proxy_set_header X-Real-IP????? $remote_addr;

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

}

}

}

4、?測試

首先單獨對nginx測試看是否工作正常，（更改hosts文件來測試！）

其次對keepalived進行測試，停掉nginx master上的keepalived，看backup服務器是否接管！

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