nginx+keepalived

Posted 2020-10-05

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。

1.1.  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。

        

2.1.  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

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 } }

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

 

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

 

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

 

##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

 

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