Nginx教程

Nginx教程
1. 课程目标
1.1. 了解反向代理和负载均衡的概念
1.2. 掌握Nginx的安装和使用
1.3. 利用Nginx实现负载均衡
2. Nginx相关概念
2.1. 反向代理
反向代理（Reverse Proxy）方式是指以代理服务器来接受internet上的连接请求，然后将请求转发给内部网络上的服务器，并将从服务器上得到的结果返回给internet上请求连接的客户端，此时代理服务器对外就表现为一个服务器。

2.2. 负载均衡
负载均衡，英文名称为Load Balance，是指建立在现有网络结构之上，并提供了一种廉价有效透明的方法扩展网络设备和服务器的带宽、增加吞吐量、加强网络数据处理能力、提高网络的灵活性和可用性。其原理就是数据流量分摊到多个服务器上执行，减轻每台服务器的压力，多台服务器共同完成工作任务，从而提高了数据的吞吐量。

1. Nginx的安装
   3.1. 下载nginx
   官网：http://nginx.org/
   3.2. 上传并解压nginx

tar -zxvf nginx-1.8.1.tar.gz -C /usr/local/src

3.3. 编译nginx
进入到nginx源码目录

cd /usr/local/src/nginx-1.8.1

检查安装环境,并指定将来要安装的路径
./configure –prefix=/usr/local/nginx
缺包报错 ./configure: error: C compiler cc is not found

使用YUM安装缺少的包
yum -y install gcc pcre-devel openssl openssl-devel

编译安装
make && make install

安装完后测试是否正常：
/usr/loca/nginx/sbin/nginx
查看端口是否有ngnix进程监听
netstat -ntlp | grep 80

1. 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所在服务器的主机名

location / { #拦截所有请求，反向代理的配置
root html;
proxy_pass http://192.168.0.21:8080; #这里是代理走向的目标服务器：tomcat
}
}
2.启动tomcat-01上的tomcat

3.启动nginx-01上的nginx
./nginx

重启:
kill -HUP cat /usr/local/nginx/logs/nginx.pid
参考网址:http://www.cnblogs.com/jianxie/p/3990377.html

4.2. 动静分离
动态资源 index.jsp

location ~ .*\.(jsp|do|action)$ {    proxy_pass http://tomcat-01.itcast.cn:8080;}

静态资源

location ~ .*\.(html|js|css|gif|jpg|jpeg|png)$ {    expires 3d;}

4.3. 负载均衡
在http这个节下面配置一个叫upstream的，后面的名字可以随意取，但是要和location下的proxy_pass http://后的保持一致。
http {
是在http里面的, 已有http, 不是在server里,在server外面
upstream tomcats {
server shizhan02:8080 weight=1;#weight表示多少个
server shizhan03:8080 weight=1;
server shizhan04:8080 weight=1;
}
卸载server里

location ~ .*\.(jsp|do|action) {    proxy_pass http://tomcats;        #tomcats是后面的tomcat服务器组的逻辑组号}}

1. 利用keepalived实现高可靠（HA）
   5.1. 高可靠概念
   HA(High Available), 高可用性集群，是保证业务连续性的有效解决方案，一般有两个或两个以上的节点，且分为活动节点及备用节点。

5.2. 高可靠软件keepalived
keepalive是一款可以实现高可靠的软件，通常部署在2台服务器上，分为一主一备。Keepalived可以对本机上的进程进行检测，一旦Master检测出某个进程出现问题，将自己切换成Backup状态，然后通知另外一个节点切换成Master状态。
5.3. keepalived安装
下载keepalived官网:http://keepalived.org

将keepalived解压到/usr/local/src目录下

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

进入到/usr/local/src/keepalived-1.2.19目录

cd /usr/local/src/keepalived-1.2.19

开始configure

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

编译并安装

make && make install

5.4. 将keepalived添加到系统服务中
拷贝执行文件

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

将init.d文件拷贝到etc下,加入开机启动项

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

将keepalived文件拷贝到etc下

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

创建keepalived文件夹

mkdir -p /etc/keepalived

将keepalived配置文件拷贝到etc下

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

添加可执行权限

chmod +x /etc/init.d/keepalived

以上所有命令一次性执行：

cp /usr/local/keepalived/sbin/keepalived /usr/sbin/cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalivedcp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ mkdir -p /etc/keepalivedcp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.confchmod +x /etc/init.d/keepalivedchkconfig --add keepalived  chkconfig keepalived on

添加keepalived到开机启动

chkconfig --add keepalived  chkconfig keepalived on

5.5. 配置keepalived虚拟IP
修改配置文件： /etc/keepalived/keepalived.conf
MASTER节点

global_defs {}vrrp_instance VI_1 {    state MASTER   #指定A节点为主节点 备用节点上设置为BACKUP即可    interface eth0    #绑定虚拟IP的网络接口    virtual_router_id 51   #VRRP组名，两个节点的设置必须一样，以指明各个节点属于同一VRRP组    priority 100   #主节点的优先级（1-254之间），备用节点必须比主节点优先级低    advert_int 1  #组播信息发送间隔，两个节点设置必须一样    authentication {    #设置验证信息，两个节点必须一致        auth_type PASS        auth_pass 1111    }    virtual_ipaddress {    #指定虚拟IP, 两个节点设置必须一样        192.168.33.60/24    #如果两个nginx的ip分别是192.168.33.61,,...62，则此处的虚拟ip跟它俩同一个网段即可    }}

BACKUP节点

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    }}

分别启动两台机器上的keepalived

service keepalived start

测试：
杀掉master上的keepalived进程，你会发现，在slave机器上的eth0网卡多了一个ip地址
查看ip地址的命令： ip addr

5.6. 配置keepalived心跳检查
原理：
Keepalived并不跟nginx耦合，它俩完全不是一家人
但是keepalived提供一个机制：让用户自定义一个shell脚本去检测用户自己的程序，返回状态给keepalived就可以了

MASTER节点

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秒执行上述的脚本，去检查用户的程序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"}

添加切换通知脚本

vi /usr/local/keepalived/sbin/notify.sh#!/bin/bashcase "$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#添加执行权限chmod +x /usr/local/keepalived/sbin/notify.shglobal_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"}

在第二台机器上添加notify.sh脚本
分别在两台机器上启动keepalived
service keepalived start
chkconfig keepalived on