Nginx教程

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Nginx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-1.8.1.tar.gz -C /usr/local/src

2.3. 编译nginx

#进入到nginx源码目录

cd /usr/local/src/nginx-1.8.1

#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

3. 配置nginx

3.1. 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
#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

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,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

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

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。

4.3. keepalived安装

下载keepalived官网:http://keepalived.org

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

4.4. keepalived添加到系统服务中

拷贝执行文件

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

init.d文件拷贝到etc,加入开机启动项

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

keepalived文件拷贝到etc

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

创建keepalived文件夹

mkdir -p /etc/keepalived

keepalived配置文件拷贝到etc

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/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

添加keepalived到开机启动

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 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
    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nginxip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

4.6. 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/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

#添加执行权限

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

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