• docker network基础


    转自:https://www.cnblogs.com/jsonhc/p/7823286.html

    前面介绍了nginx与php两个容器间是如何进行通信的:

    [root@docker ~]# docker run -d --name=php -v /www:/usr/local/nginx/html php
    [root@docker ~]# docker run -d --name=nginx --link=php:php -v /www:/usr/local/nginx/html -p 81:80 nginx
    [root@docker ~]# docker ps -a
    CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                NAMES
    58280fe851f9        nginx               "/usr/local/nginx/..."   15 seconds ago      Up 14 seconds       0.0.0.0:81->80/tcp   nginx
    9ea150c35587        php                 "/usr/local/php/sb..."   36 seconds ago      Up 35 seconds       9000/tcp             php

    通过容器间的选项--link指定容器名称进行不同容器间的通信(--link container_name或者将container_name取一个别名)

    现在使用另外一种方式替代--link来达到容器间的通信:docker network

    查看local的网络信息:

    [root@docker ~]# docker network ls
    NETWORK ID          NAME                DRIVER              SCOPE
    5133ec415c3c        bridge              bridge              local
    f359ca4e2d39        host                host                local
    8d68673c045c        none                null                local

    现在创建一个网络名为my_net且driver为bridge的网络:(默认创建的就是bridge)

    复制代码
    [root@docker ~]# docker network create my_net
    67e29f0e4a77c79144efc337a081a889188b5b8e289968f22be6e4ddd9b80610
    [root@docker ~]# docker network ls
    NETWORK ID          NAME                DRIVER              SCOPE
    5133ec415c3c        bridge              bridge              local
    f359ca4e2d39        host                host                local
    67e29f0e4a77        my_net              bridge              local
    8d68673c045c        none                null                local
    复制代码

    利用--network启动容器提供服务:

    [root@docker ~]# docker run -d --name=php --network my_net --network-alias php -v /www:/usr/local/nginx/html php
    6b493cbe8207dee4cb4d5945cfce305dba96914083bd7f46841b0b42376bcb99
    [root@docker ~]# docker run -d --name=nginx --network my_net --network-alias nginx -v /www:/usr/local/nginx/html -p 80:80 nginx
    5ab220196b52bb768bef508433f0b920eecee70c3ee47880ebc5e2a74b5ee254

    通过选项--network-alias将取名的my_net起了一个别名

    [root@docker ~]# docker exec -it nginx ping php
    PING php (172.18.0.2) 56(84) bytes of data.
    64 bytes from php.my_net (172.18.0.2): icmp_seq=1 ttl=64 time=0.079 ms
    64 bytes from php.my_net (172.18.0.2): icmp_seq=2 ttl=64 time=0.090 ms

    这里为啥能够ping通过php这个容器呢,因为这两个容器在同一个网络m'y_net内,而nginx里面ping的php是容器名(这里管理的是容器级别)

    由于能够ping通php,所以在nginx中配置的:

    复制代码
    server {
        listen   80;
        root /usr/local/nginx/html;
        index index.htm index.html index.php;
        location ~ .php$ {
            root /usr/local/nginx/html;
            fastcgi_pass php:9000;
            fastcgi_index index.php;
            fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
            include fastcgi_params;
        } 
    }
    复制代码

    所以配置文件中的php不会导致nginx启动失败,通过network的driver bridge实现了容器间的访问

    上面在容器启动的时候使用的是选项--network,而在compose的配置文件中则是networks,现在通过配置文件来进行阐述该参数的作用:

    复制代码
    [root@docker lnmp]# cat lnmp.yml 
    version: '3'
    services:
      nginx:
        image: nginx
        container_name: lnmp-nginx
        depends_on:
          - php
        ports:
          - "80:80"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
      php:
        image: php
        container_name: lnmp-php
        expose: 
          - "9000"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
    
    networks:
      net1:
        driver: bridge
    复制代码

    由上述文件中可以知道networks定义了一个名称为net1的网络,由于networks是top-level(顶层级别,所以需要在顶层设置),而在创建的网络时候需要指定driver(单一网络使用bridge,swarm集群使用overlay),而且driver内容不能省略,在nginx和php两个service中使用了同一网络net1,现在将服务启动:

    复制代码
    [root@docker lnmp]# docker-compose -f lnmp.yml up
    Creating network "lnmp_net1" with driver "bridge"
    Creating lnmp-php ... 
    Creating lnmp-php ... done
    Creating lnmp-nginx ... 
    Creating lnmp-nginx ... done
    Attaching to lnmp-php, lnmp-nginx
    复制代码

    可以看出在启动服务的时候创建了服务级别的网络lnmp_net1

    复制代码
    [root@docker lnmp]# docker network ls
    NETWORK ID          NAME                DRIVER              SCOPE
    5133ec415c3c        bridge              bridge              local
    f359ca4e2d39        host                host                local
    29d798852b52        lnmp_net1           bridge              local
    67e29f0e4a77        my_net              bridge              local
    8d68673c045c        none                null                local
    复制代码

    服务nginx和php在网络lnmp_net1实现了互联通信

    [root@docker lnmp]# docker-compose -f lnmp.yml exec nginx ping php
    PING php (172.19.0.2) 56(84) bytes of data.
    64 bytes from lnmp-php.lnmp_net1 (172.19.0.2): icmp_seq=1 ttl=64 time=0.060 ms

    在nginx服务中能够访问php的服务,在compose编排中级别的访问是对service级别的访问,所以在nginx服务配置文件中对应的php能够实现,不会导致nginx启动失败

    及在compose的配置文件设置并对应的是service级别,当使用参数links也是配置的php服务,使得nginx服务能够ping通php服务并实现访问通信

    复制代码
    [root@docker lnmp]# cat lnmp.yml
    version: '3'
    services:
      nginx:
        image: nginx
        container_name: lnmp-nginx
        depends_on:
          - php
        ports:
          - "80:80"
        links:
          - php:php
        volumes:
          - "/www:/usr/local/nginx/html"
      php:
        image: php
        container_name: lnmp-php
        expose: 
          - "9000"
        volumes:
          - "/www:/usr/local/nginx/html"
    复制代码

    将networks参数改为了links参数,使得两个服务能够继续互联访问

    复制代码
    [root@docker lnmp]# docker-compose -f lnmp.yml up
    Creating network "lnmp_default" with the default driver
    Creating lnmp-php ... 
    Creating lnmp-php ... done
    Creating lnmp-nginx ... 
    Creating lnmp-nginx ... done
    Attaching to lnmp-php, lnmp-nginx
    复制代码

    而且启动的时候创建的默认的网络

    [root@docker lnmp]# docker-compose -f lnmp.yml exec nginx ping php
    PING php (172.19.0.2) 56(84) bytes of data.
    64 bytes from lnmp-php.lnmp_default (172.19.0.2): icmp_seq=1 ttl=64 time=0.091 ms
    64 bytes from lnmp-php.lnmp_default (172.19.0.2): icmp_seq=2 ttl=64 time=0.107 ms

    --links也是能够使得服务间进行访问的

    现在通过案例讲解参数external_links的作用:external_links类似于links针对的也是service级别,但是external_links对应的是外部的service而不是同一compose配置文件中的service

    复制代码
    [root@docker lnmp]# cat lnmp.yml
    version: '3'
    services:
      nginx:
        image: nginx
        container_name: lnmp-nginx
        depends_on:
          - php
        ports:
          - "80:80"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
        external_links:
          - php1:php
      php:
        image: php
        container_name: lnmp-php
        expose: 
          - "9000"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
    
    networks:
      net1:
        driver: bridge
    复制代码

    上面可以看见external_links配置了php1的服务,并且将php1的服务也取别名为了php,然后编写另一个compose配置文件,并配置服务名为php1的服务:

    复制代码
    [root@docker lnmp]# cat php1.yml 
    version: '3'
    services:
      php1:
        image: php
        container_name: lnmp-php1
        expose: 
          - "9000"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
    
    networks:
      net1:
        driver: bridge
    复制代码

    结合两个compose配置文件,可以知道有nginx、php、php1的服务,并且php1的服务也有php的别名,现在依次开启php1,和nginx与php:

    [root@docker lnmp]# docker-compose -f php1.yml up
    Creating network "lnmp_net1" with driver "bridge"
    Creating lnmp-php1 ... 
    Creating lnmp-php1 ... done
    Attaching to lnmp-php1
    复制代码
    [root@docker lnmp]# docker-compose -f lnmp.yml up --build
    WARNING: Found orphan containers (lnmp-php1) for this project. If you removed or renamed this service in your compose file, you can run this command with the --remove-orphans flag to clean it up.
    Creating lnmp-php ... 
    Creating lnmp-php ... done
    Creating lnmp-nginx ... 
    Creating lnmp-nginx ... done
    Attaching to lnmp-php, lnmp-nginx
    复制代码

    查看启动的容器状态:

    [root@docker www]# docker ps -a
    CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                NAMES
    a089cd261279        nginx               "/usr/local/nginx/..."   25 seconds ago      Up 25 seconds       0.0.0.0:80->80/tcp   lnmp-nginx
    4ff4bf7c1bf9        php                 "/usr/local/php/sb..."   25 seconds ago      Up 25 seconds       9000/tcp             lnmp-php
    4e39cdf62bf1        php                 "/usr/local/php/sb..."   51 seconds ago      Up 51 seconds       9000/tcp             lnmp-php1

    现在将nginx一起的php的这个服务停止掉,看下nginx服务是否将会被停止:

    [root@docker lnmp]# docker-compose -f lnmp.yml stop php
    Stopping lnmp-php ... done

    而在nginx这里的输出如下:

    lnmp-php exited with code 0
    [root@docker www]# docker ps -a
    CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                      PORTS                NAMES
    a089cd261279        nginx               "/usr/local/nginx/..."   2 minutes ago       Up 2 minutes                0.0.0.0:80->80/tcp   lnmp-nginx
    4ff4bf7c1bf9        php                 "/usr/local/php/sb..."   2 minutes ago       Exited (0) 52 seconds ago                        lnmp-php

    而php服务对应的容器lnmp-php也停止了,但是nginx的服务却没有停止,为什么呢?那是因为php1的服务并没有停止,而php1的服务也是别名php服务的,而external_links就是实现这种情况的

    使一个compose中的服务能与另一个compose中的服务能够互联通信,compose就是service级别的实现,配置文件中对应的都是service级别,而不是容器名

    而在另一个compose中也必须定义与之相同的网络名称,也就是说配置external_links时,两者服务间的网络名称必须一致,不然依旧不能进行互相访问

    当使用了external_links时,必须启动另一个compose的service,如果仅仅启动的是包含此函数的compose那么service将会启动报错

    复制代码
    [root@docker lnmp]# cat lnmp.yml_external_links 
    version: '3'
    services:
      nginx:
        image: nginx
        container_name: lnmp-nginx
        depends_on:
          - php
        ports:
          - "80:80"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
        external_links:
          - php1:php
      php:
        image: php
        container_name: lnmp-php
        expose: 
          - "9000"
        networks:
          - "net1"
        volumes:
          - "/www:/usr/local/nginx/html"
    
    networks:
      net1:
        driver: bridge
    复制代码
    复制代码
    [root@docker lnmp]# docker-compose -f lnmp.yml up --build
    Creating network "lnmp_net1" with driver "bridge"
    Creating lnmp-php ... 
    Creating lnmp-php ... done
    Creating lnmp-nginx ... 
    Creating lnmp-nginx ... done
    Attaching to lnmp-php, lnmp-nginx
    lnmp-nginx | nginx: [emerg] host not found in upstream "php" in /usr/local/nginx/conf/vhost/www.conf:7
    lnmp-nginx exited with code 1
    复制代码

    参数external_links连接的外部php服务并没有启动,所以nginx还是启动报错

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  • 原文地址:https://www.cnblogs.com/maohuidong/p/9914815.html
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