Nginx配置教程

1. Nginx相关概念

1.1 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。

1.2 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。

2. Nginx的安装

2.1.  下载nginx

官网：http://nginx.org/

2.2.  上传并解压nginx

tar -zxvf nginx-1.8..tar.gz -C /usr/local/src

2.3.  编译nginx

#进入到nginx源码目录

cd /usr/local/src/nginx-1.8. 

#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 

3. 配置Nginx

3.1 配置反向代理

1.修改nginx配置文件

server {
    listen       ;
    server_name  nginx-.itcast.cn;    #nginx所在服务器的主机名
#反向代理的配置
location / {             #拦截所有请求
    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

3.2 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;
}

3.3 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: weight=;#weight表示多少个
        server shizhan03: weight=;
        server shizhan04: weight=;
}
#写在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
}
}

4. 利用keepalived实现高可靠（HA）

4.1 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。

4.2 高可靠软件keepalived

keepalived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。

4.3 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..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.

开始configure

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

#编译并安装

make && make install

4.4 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 

添加keepalived到开机启动

chkconfig --add keepalived
chkconfig keepalived on

##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/keepalived
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir -p /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf
chmod +x /etc/init.d/keepalived
chkconfig --add keepalived
chkconfig keepalived on

4.5 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    #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    #主节点的优先级（-254之间），备用节点必须比主节点优先级低
    advert_int   #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
    }
    virtual_ipaddress {    #指定虚拟IP, 两个节点设置必须一样
        192.168.33.60/    #如果两个nginx的ip分别是192.168.33.,,...，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
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass
    }
    virtual_ipaddress {
        192.168.33.60/
    }
}

#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

4.6 配置keepalived心跳检查

原理：

Keepalived并不跟nginx耦合，它俩完全没有任何关系。

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     #每隔1秒执行上述的脚本，去检查用户的程序ngnix
    weight -
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass
    }

    track_script {
        chk_health
    }

    virtual_ipaddress {
        10.0.0.10/
    }

    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/bash

case "$1" in
    master)
        /usr/local/nginx/sbin/nginx
        exit
    ;;
backup)
        /usr/local/nginx/sbin/nginx -s stop
        /usr/local/nginx/sbin/nginx
        exit
    ;;
    fault)
        /usr/local/nginx/sbin/nginx -s stop
        exit
    ;;
    *)
        echo 'Usage: notify.sh {master|backup|fault}'
        exit
    ;;
esac

#添加执行权限

chmod +x /usr/local/keepalived/sbin/notify.sh

#在第二台机器上添加notify.sh脚本

global_defs {
}

vrrp_script chk_health {
    script "[[ `ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"
    interval
    weight -
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass
    }

    track_script {
        chk_health
    }

    virtual_ipaddress {
        10.0.0.10/
    }

    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"
}

#分别在两台机器上启动keepalived

service keepalived start
chkconfig keepalived on