Nginx教程

02-10

Nginx教程

1. 課程目標

1.1. 了解反向代理和負載均衡的概念

1.2. 掌握Nginx的安裝和使用

1.3. 利用Nginx實現負載均衡

2. Nginx相關概念

2.1. 反向代理

反向代理（Reverse Proxy）方式是指以代理伺服器來接受internet上的連接請求，然後將請求轉發給內部網路上的伺服器，並將從伺服器上得到的結果返回給internet上請求連接的客戶端，此時代理伺服器對外就表現為一個伺服器。

2.2. 負載均衡

負載均衡，英文名稱為Load Balance，是指建立在現有網路結構之上，並提供了一種廉價有效透明的方法擴展網路設備和伺服器的帶寬、增加吞吐量、加強網路數據處理能力、提高網路的靈活性和可用性。其原理就是數據流量分攤到多個伺服器上執行，減輕每台伺服器的壓力，多台伺服器共同完成工作任務，從而提高了數據的吞吐量。

3. Nginx的安裝

3.1. 下載nginx

官網：http://nginx.org/

3.2. 上傳並解壓nginx

tar -zxvf nginx-1.8.1.tar.gz -C

/usr/local/src

3.3. 編譯nginx

#進入到nginx源碼目錄

cd /usr/local/src/nginx-1.8.1

#檢查安裝環境,並指定將來要安裝的路徑

./configure --prefix=/usr/local/nginx

#缺包報錯 ./configure: error: C compiler cc is not found

#使用YUM安裝缺少的包

yum

-y install gcc pcre-devel openssl openssl-devel

#編譯安裝

make

&& make install

安裝完後測試是否正常：

/usr/loca/nginx/sbin/nginx

查看埠是否有ngnix進程監聽

netstat

-ntlp | grep 80

4. 配置nginx

4.1. 配置反向代理

1.修改nginx配置文件

server {

listen 80;

server_name nginx-01.itcast.cn; #nginx所在伺服器的主機名

#反向代理的配置

location / { #攔截所有請求

root html;

proxy_pass http://192.168.0.21:8080; #這裡是代理走向的目標伺服器：tomcat

}

2.啟動tomcat-01上的tomcat

3.啟動nginx-01上的nginx

./nginx

重啟:

kill -HUP `cat /usr/local/nginx/logs/nginx.pid

參考網址:http://www.cnblogs.com/jianxie/p/3990377.html

4.2. 動靜分離

#動態資源 index.jsp

location ~ .*.(jsp|do|action)$ {

proxy_pass http://tomcat-01.itcast.cn:8080;

}

#靜態資源

location ~

.*.(html|js|css|gif|jpg|jpeg|png)$ {

expires 3d;

}

4.3. 負載均衡

在http這個節下面配置一個叫upstream的，後面的名字可以隨意取，但是要和location下的proxy_pass http://後的保持一致。

http {

是在http裡面的, 已有http, 不是在server里,在server外面

upstream tomcats

{

server shizhan02:8080 weight=1;#weight表示多少個

server shizhan03:8080 weight=1;

server shizhan04:8080 weight=1;

}

#卸載server里

location ~ .*.(jsp|do|action) {

proxy_pass http://tomcats; #tomcats是後面的tomcat伺服器組的邏輯組號

}

5. 利用keepalived實現高可靠（HA）

5.1. 高可靠概念

HA(High Available), 高可用性集群，是保證業務連續性的有效解決方案，一般有兩個或兩個以上的節點，且分為活動節點及備用節點。

5.2. 高可靠軟體keepalived

keepalive是一款可以實現高可靠的軟體，通常部署在2台伺服器上，分為一主一備。Keepalived可以對本機上的進程進行檢測，一旦Master檢測出某個進程出現問題，將自己切換成Backup狀態，然後通知另外一個節點切換成Master狀態。

5.3. keepalived安裝

下載keepalived官網:http://keepalived.org

將keepalived解壓到/usr/local/src目錄下

tar -zxvf keepalived-1.2.19.tar.gz -C /usr/local/src

進入到/usr/local/src/keepalived-1.2.19目錄

cd /usr/local/src/keepalived-1.2.19

開始configure

./configure

--prefix=/usr/local/keepalived

#編譯並安裝

make && make install

5.4. 將keepalived添加到系統服務中

拷貝執行文件

cp /usr/local/keepalived/sbin/keepalived

/usr/sbin/

將init.d文件拷貝到etc下,加入開機啟動項

cp /usr/local/keepalived/etc/rc.d/init.d/keepalived

/etc/init.d/keepalived

將keepalived文件拷貝到etc下

cp /usr/local/keepalived/etc/sysconfig/keepalived

/etc/sysconfig/

創建keepalived文件夾

mkdir -p

/etc/keepalived

將keepalived配置文件拷貝到etc下

cp /usr/local/keepalived/etc/keepalived/keepalived.conf

/etc/keepalived/keepalived.conf

添加可執行許可權

chmod

+x/etc/init.d/keepalived

##以上所有命令一次性執行：

/usr/local/keepalived/sbin/keepalived /usr/sbin/

/usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalived

/usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

mkdir

-p /etc/keepalived

/usr/local/keepalived/etc/keepalived/keepalived.conf

/etc/keepalived/keepalived.conf

chmod

+x /etc/init.d/keepalived

chkconfig

--add keepalived

chkconfig

keepalived on

添加keepalived到開機啟動

chkconfig --add keepalived

chkconfig keepalived on

5.5. 配置keepalived虛擬IP

修改配置文件： /etc/keepalived/keepalived.conf

#MASTER節點

global_defs {

}

vrrp_instance

VI_1 {

state MASTER #指定A節點為主節點備用節點上設置為BACKUP即可

interface eth0 #綁定虛擬IP的網路介面

virtual_router_id 51 #VRRP組名，兩個節點的設置必須一樣，以指明各個節點屬於同一VRRP組

priority 100 #主節點的優先順序（1-254之間），備用節點必須比主節點優先順序低

advert_int 1 #組播信息發送間隔，兩個節點設置必須一樣

authentication { #設置驗證信息，兩個節點必須一致

auth_type PASS

auth_pass 1111

}

virtual_ipaddress { #指定虛擬IP, 兩個節點設置必須一樣

192.168.33.60/24 #如果兩個nginx的ip分別是192.168.33.61,,...62，則此處的虛擬ip跟它倆同一個網段即可

}

#BACKUP節點

global_defs {

}

vrrp_instance

VI_1 {

state BACKUP

interface eth0

virtual_router_id 51

priority 99

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.33.60/24

}

#分別啟動兩台機器上的keepalived

service keepalived start

測試：

殺掉master上的keepalived進程，你會發現，在slave機器上的eth0網卡多了一個ip地址

查看ip地址的命令： ip addr

5.6. 配置keepalived心跳檢查

原理：

Keepalived並不跟nginx耦合，它倆完全不是一家人

但是keepalived提供一個機制：讓用戶自定義一個shell腳本去檢測用戶自己的程序，返回狀態給keepalived就可以了

#MASTER節點

global_defs {

}

vrrp_script chk_health {

script "[[

`ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 ||

exit 1"

interval 1 #每隔1秒執行上述的腳本，去檢查用戶的程序ngnix

weight -2

}

vrrp_instance

VI_1 {

state MASTER

interface eth0

virtual_router_id 1

priority 100

advert_int 2

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_health

}

virtual_ipaddress {

10.0.0.10/24

}

notify_master

"/usr/local/keepalived/sbin/notify.sh master"

notify_backup

"/usr/local/keepalived/sbin/notify.sh backup"

notify_fault

"/usr/local/keepalived/sbin/notify.sh fault"

}

#添加切換通知腳本

vi /usr/local/keepalived/sbin/notify.sh

#!/bin/bash

case

"$1" in

master)

/usr/local/nginx/sbin/nginx

exit 0

;;

backup)

/usr/local/nginx/sbin/nginx -s stop

/usr/local/nginx/sbin/nginx

exit 0

;;

fault)

/usr/local/nginx/sbin/nginx -s stop

exit 0

;;

echo Usage: notify.sh

{master|backup|fault}

exit 1

;;

esac

#添加執行許可權

chmod +x

/usr/local/keepalived/sbin/notify.sh

global_defs {

}

vrrp_script

chk_health {

script "[[ `ps -ef | grep nginx |

grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"

interval 1

weight -2

}

vrrp_instance

VI_1 {

state BACKUP

interface eth0

virtual_router_id 1

priority 99

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_health

}

virtual_ipaddress {

10.0.0.10/24

}

notify_master

"/usr/local/keepalived/sbin/notify.sh master"

notify_backup "/usr/local/keepalived/sbin/notify.sh

backup"

notify_fault

"/usr/local/keepalived/sbin/notify.sh fault"

}

#在第二台機器上添加notify.sh腳本

#分別在兩台機器上啟動keepalived

service keepalived start

chkconfig keepalived on

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