docker_容器間的連結 link

使用link就是類似使用了容器的ip位址，無需知道其真實ip，使用link後的别名就可以知道

使用link連接配接容器

以 mysql 為 栗子

1. 啟動一個 mysql-server，詳細參數可以參照說明文檔：https://hub.docker.com/r/mysql/mysql-server/，設定密碼，挂載資料庫 等等

   wilker@ubuntu:~$ docker pull mysql/mysql-server # 拉一個官方的鏡像下來
   wilker@ubuntu:~$ docker run --name=mysql_server11 -e MYSQL_ROOT_PASSWORD= -d mysql/mysql-server # 啟動容器，并設定 root 使用者密碼
              

2. 進入 mysql_server11 容器中修改一下 root 使用者可以通路的ip位址，預設是 localhost，别的ip是連不進來的，這裡改成 任意 ip 都可以連進來（生産環境不能這樣幹）

   [email protected]:~$ docker exec -it mysql_server11 mysql -uroot -p123456 # 進入容器的mysql服務
   mysql: [Warning] Using a password on the command line interface can be insecure.
   Welcome to the MySQL monitor.  Commands end with ; or \g.
   Your MySQL connection id is 4
   Server version: 5.7.18 MySQL Community Server (GPL)
   
   mysql> show databases; # 看下預設的資料庫
   +--------------------+
   | Database           |
   +--------------------+
   | information_schema |
   | mysql              |
   | performance_schema |
   | sys                |
   +--------------------+
   
   mysql> use mysql; # 使用 mysql 資料庫
   Database changed
   mysql> select host,user from user where user='root';
   +-----------+------+
   | host      | user |
   +-----------+------+
   | localhost | root | # 預設隻有 目前容器能用 root 使用者連進來，要修改一下
   +-----------+------+
   1 row in set (0.00 sec)
   
   mysql> update user set host = '%'  where user ='root'; # 修改成 % 表示任意ip
   Query OK, 1 row affected (0.03 sec)
   Rows matched: 1  Changed: 1  Warnings: 0
   
   mysql> select host,user from user where user='root'; # 檢視一下修改成功沒
   +------+------+
   | host | user |
   +------+------+
   | %    | root |
   +------+------+
   1 row in set (0.00 sec)
   
   mysql> flush privileges; # 重新整理權限使之生效
   Query OK, 0 rows affected (0.01 sec)
   
   mysql> exit; # 退出 mysql，然後自動退出容器
   Bye
   [email protected]:~$
              

3. 去 docker hub 拉一個用戶端下來，使用 link 連接配接 mysql_server11 容器，并使用别名 為 db

   [email protected]:~$ docker pull imega/mysql-client # 拉 mysql 用戶端鏡像
   [email protected]:~$ docker run --name=mysql_client11 --link=mysql_server11:db -i -t imega/mysql-client mysql -h db -uroot -p123456 # -h 的值為 db，就是 mysql_server11 的ip别名
   Welcome to the MariaDB monitor.  Commands end with ; or \g.
   Your MySQL connection id is 
   Server version:  MySQL Community Server (GPL)
   
   Copyright (c) , , Oracle, MariaDB Corporation Ab and others.
   
   Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
   
   MySQL [(none)]> show databases; # 成功進入 mysql_server11 容器中的資料庫
   +--------------------+
   | Database           |
   +--------------------+
   | information_schema |
   | mysql              |
   | performance_schema |
   | sys                |
   +--------------------+
    rows in set ( sec)
   
   MySQL [(none)]> exit;
   Bye
              

   • 退出用戶端容器是容器也就變為 Exit 狀态了，再次進入可以用 start 這個容器

     [email protected]:~$ docker start mysql_client11 -a 
     Welcome to the MariaDB monitor.  Commands end with ; or \g.
     Your MySQL connection id is 
     Server version:  MySQL Community Server (GPL)
     
     Copyright (c) , , Oracle, MariaDB Corporation Ab and others.
     
     Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
     
     MySQL [(none)]> 
                

檢視容器連接配接後的環境變量

還是用上面運作的 mysql 栗子

• mysql_server11 的環境變量

  wilker@ubuntu:~$ docker exec mysql_server11 env
  PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
  HOSTNAME=e3edaf102b4a
  MYSQL_ROOT_PASSWORD=
  PACKAGE_URL=https://repo.mysql.com/yum/mysql-5.7-community/docker/x86_64/mysql-community-server-minimal-.-.el7.x86_64.rpm
  HOME=/root
             

• mysql_client11 的環境變量，這裡可以看到 mysql_server11 容器的環境變量

  [email protected]:~$ docker exec mysql_client11 env  
  PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
  HOSTNAME=db696da76b9c
  DB_PORT=tcp://172.17.0.2:3306
  DB_PORT_3306_TCP=tcp://172.17.0.2:3306
  DB_PORT_3306_TCP_ADDR=172.17.0.2
  DB_PORT_3306_TCP_PORT=3306
  DB_PORT_3306_TCP_PROTO=tcp
  DB_PORT_33060_TCP=tcp://172.17.0.2:33060
  DB_PORT_33060_TCP_ADDR=172.17.0.2
  DB_PORT_33060_TCP_PORT=33060
  DB_PORT_33060_TCP_PROTO=tcp
  DB_NAME=/mysql_client11/db
  DB_ENV_MYSQL_ROOT_PASSWORD=123456
  DB_ENV_PACKAGE_URL=https://repo.mysql.com/yum/mysql-5.7-community/docker/x86_64/mysql-community-server-minimal-5.7.18-1.el7.x86_64.rpm
  HOME=/root
             

  • 再看一下 hosts 檔案, db 可以解析為 172.17.0.2，

  [email protected]:~$ docker exec mysql_client11 cat /etc/hosts
  127.0.0.1       localhost
  ::1     localhost ip6-localhost ip6-loopback
  fe00::0 ip6-localnet
  ff00::0 ip6-mcastprefix
  ff02::1 ip6-allnodes
  ff02::2 ip6-allrouters
  172.17.0.2      db e3edaf102b4a mysql_server11
  172.17.0.3      db696da76b9c
             

參考資料

• http://blog.tingyun.com/web/article/detail/892
• http://www.jianshu.com/p/13752117ff97
• https://www.oschina.net/translate/dockerlinks
• mysql 的相關操作：http://www.cnblogs.com/flying607/p/4766041.html