[开启大数据的大门] 第二天:Nginx教程+keepalived

ゞ浴缸里的玫瑰 2022-04-24 01:02 189阅读 0赞

## 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。`  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI2MjgyODY5_size_16_color_FFFFFF_t_70]

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。`  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI2MjgyODY5_size_16_color_FFFFFF_t_70 1]

**3.Nginx的安装**  
3.1.下载nginx  
    官网：[http://nginx.org/][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`

**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 -HUPcat /usr/local/nginx/logs/nginx.pid`  
    参考网址:[http://www.cnblogs.com/jianxie/p/3990377.html][http_www.cnblogs.com_jianxie_p_3990377.html]  
![在这里插入图片描述][20190411142222769.png]

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]。

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 权重
            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
    	}
    }

**5.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。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI2MjgyODY5_size_16_color_FFFFFF_t_70 2]

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][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(总结)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`

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_     调用后面自定义的脚本
        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(上面的自定义脚本)**  
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

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI2MjgyODY5_size_16_color_FFFFFF_t_70]: /images/20220221/f3d0e2654b95482db46ee7ba697359b5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI2MjgyODY5_size_16_color_FFFFFF_t_70 1]: /images/20220221/f45e27e126454e778d88c43857ee1733.png
[http_nginx.org]: http://nginx.org/
[http_www.cnblogs.com_jianxie_p_3990377.html]: http://www.cnblogs.com/jianxie/p/3990377.html
[20190411142222769.png]: /images/20220221/559035546fbd4b868abcb0c02fe45438.png
[http]: http://xn--4gq38b75fotts5wbhp
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI2MjgyODY5_size_16_color_FFFFFF_t_70 2]: /images/20220221/4feac73f89264caf95672eea1fc7d0da.png
[http_keepalived.org]: http://keepalived.org