nginx 集群部署

介绍：通过单个服务器部署的伪集群，借助docker的自定义网络，定义多个ip来模拟多台服务器。

一. 双机热备模式

节点信息
docker-compose.yml：docker编排配置文件，主要指定服务，指定打包当前服务部署所使用的镜像的文件（dockerfile），指定网络。
Dockerfile：就是docker-compose文件中制定的需要打包镜像的镜像文件。
entrypoint.sh：容器中要执行的启动脚本。
index-xx.html：这个是Nginx里的挂载的默认打开地址，这里只是为了可观测性配置。
keepalived-xx.conf：keepalived的配置文件，监听nginx健康状态，主节点挂掉自动用上备份。

haproxy.conf：提供一个虚拟的路径，统一的去接收用户的请求。
conf: nginx配置文件。
log: nginx日志文件。

二. 搭建流程

编写Dockerfile制作nginx-keepalived的镜像

FROM nginx:1.19.2-alpine

RUN apk update && apk upgrade

RUN apk add --no-cache bash curl ipvsadm iproute2 openrc keepalived && rm -f /var/cache/apk/* /tmp/*

COPY entrypoint.sh /entrypoint.sh

RUN chmod +x /entrypoint.sh

CMD ["/entrypoint.sh"]

创建启动脚本entrypoint.sh

#!/bin/sh
 
/usr/sbin/keepalived -n -l -D -f /etc/keepalived/keepalived.conf --dont-fork --log-console &
 
nginx -g "daemon off;"

创建docker-compose.yml文件编排容器

version: '3'

services:
  # 主服务
  nginx_master:  
    build:
      context: ./
      # 指定打镜像的镜像文件
      dockerfile: ./Dockerfile
    # 镜像挂载
    restart: always
    volumes:
      - ./keepalived-master.conf:/etc/keepalived/keepalived.conf
      - /opt/nginx/conf/nginx.conf:/etc/nginx/nginx.conf
      - /opt/nginx/conf/conf.d/default.conf:/etc/nginx/conf.d/default.conf
      - /opt/nginx/html/index-master.html:/usr/share/nginx/html/index.html
      - /opt/nginx/data:/opt/data
      - /opt/nginx/logs:/var/log/nginx
    # 容器网络
    networks:
      static-network:
        ipv4_address: 172.21.128.2
    cap_add: 
      - NET_ADMIN
  # 辅服务（以下配置参考主服务）
  nginx_slave:
    build:
      context: ./
      dockerfile: ./Dockerfile
    restart: always
    volumes:
      - ./keepalived-slave.conf:/etc/keepalived/keepalived.conf
      - /opt/nginx/conf/nginx.conf:/etc/nginx/nginx.conf
      - /opt/nginx/conf/conf.d/default.conf:/etc/nginx/conf.d/default.conf
      - /opt/nginx/html/index-slave.html:/usr/share/nginx/html/index.html
      - /opt/nginx/data:/opt/data
      - /opt/nginx/logs:/var/log/nginx
    networks:
      static-network:
        ipv4_address: 172.21.128.3
    cap_add:
        - NET_ADMIN  

  # 代理，为了解决容器IP映射到本机
  proxy:
    image: haproxy:1.7-alpine
    # 代理，监听的端口，外界端口是8000。映射到haproxy的6301端口上
    ports:
      - 8000:6301
    volumes:
      - ./haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg
    networks:
      - static-network
      
# 指定网络
networks:
  static-network:
    ipam:
      config:
        - subnet: 172.21.0.0/16

创建keepalived配置文件
keepalived-master.conf

# nx的健康状态
vrrp_script chk_nginx {
    script "pidof nginx"
    interval 2
}
 
vrrp_instance VI_1 {
    # master负责接收用户的请求，当master宕掉后才会有slave接收
    state MASTER
    # 容器内部的网卡名称
    interface eth0
    # 虚拟路由ID
    virtual_router_id 33
    # 优先级，很重要
    priority 200
    advert_int 1
    unicast_src_ip 172.21.128.2
    unicast_peer {
        172.21.128.3
    }
    
    authentication {
        auth_type PASS
        auth_pass letmein
    }
    
    # 虚拟IP地址，很重要
    virtual_ipaddress {
        172.21.128.4/24 dev eth0
    }
 
    track_script {
        chk_nginx
    }
}

keepalived-slave.conf

vrrp_script chk_nginx {
    script "pidof nginx"
    interval 2
}
 
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 33
    priority 100
    advert_int 1
    unicast_src_ip 172.21.128.3
    unicast_peer {
        172.21.128.2
    }
    
    authentication {
        auth_type PASS
        auth_pass letmein
    }
    
    virtual_ipaddress {
        172.21.128.4/24 dev eth0
    }
    
    track_script {
        chk_nginx
    }
}

haproxy.cfg

global
    log 127.0.0.1 local0
    maxconn 4096
    daemon
    nbproc 4
defaults
    log 127.0.0.1 local3
    mode http
    option dontlognull
    option redispatch
    retries 2
    maxconn 2000
    balance roundrobin
    timeout connect 5000ms
    timeout client 5000ms
    timeout server 5000ms    
listen web1
    bind :8080
    mode http
    server app1 172.21.128.4:8080
listen web2
    bind :8002
    mode http
    server app2 172.21.128.4:8002
listen web3
    bind :8003
    mode http
    server app3 172.21.128.4:8003
listen web4
    bind :8004
    mode http
    server app4 172.21.128.4:8004

创建index.html验证文件
index-master.html

<h1>this is nginx-master</h1>

index-slave.html

<h1>this is nginx-slave</h1>

访问index页面http://172.16.7.108:8000
在这里插入图片描述
模拟master宕机docker pause 088
再次访问http://172.16.7.108:8000

已经切换到从节点
重新运行主节点docker unpause 088

nginx 集群部署

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