docker端口映射和容器互相访问

端口映射

容器运行时如果没有指定端口，与外界是无法通信的，比如当前我们的有一台MySQL的docker container，当前容器正在运行mysql并提供3306端口

# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
2e54153e56ca        mysql:version1      "/bin/bash"         8 days ago          Up About a minute                       mysql-new-container

# docker exec -it mysql-new-container /bin/bash -c "netstat -antlp |grep 3306"
tcp6       0      0 :::3306                 :::*                    LISTEN      -                   

此时我们并未做端口映射，所以宿主机和外界是无法访问该MySQL服务的

将容器关机，重开机时进行端口映射

先将容器内的Mysql服务停止

# docker exec -u mysqladmin -it mysql-new-container /bin/bash -c "/usr/local/mysql/bin/mysqladmin -uroot -pmypna123 shutdown"

停止容器

# docker stop mysql-new-container
mysql-new-container

根据容器创建一个image镜像

# docker commit mysql-new-container mysql-new-container-temp
sha256:2f516f00086e5bd6f52bb90b75f03a763eaff08f62a93b6cd73d1eb0226571fe

# docker images
REPOSITORY                 TAG                 IMAGE ID            CREATED             SIZE
mysql-new-container-temp   latest              2f516f00086e         seconds ago       333MB
mysql                      version1            bf6b23f800ed         weeks ago         333MB
centos                     latest              0f3e07c0138f         weeks ago         220MB

删除容器

# docker rm mysql-new-container
mysql-new-container

根据镜像新建容器并启动会mysql

# docker run --name mysql-new-container --hostname mysql-new-container --mount type=volume,source=mysql-new-vol,target=/usr/local/mysql -p : -it mysql-new-container-temp /bin/bash
# docker ps
CONTAINER ID        IMAGE                      COMMAND             CREATED             STATUS              PORTS                    NAMES
bdc71602ee74        mysql-new-container-temp   "/bin/bash"          minutes ago       Up  minutes        0.0.0.0:->/tcp   mysql-new-container

# docker exec -u mysqladmin -it mysql-new-container /bin/bash
$ cd /usr/local/mysql/bin
$ mysqld_safe &

查看该容器的端口映射信息

# docker port mysql-new-container
/tcp -> 0.0.0.0:

测试端口映射，访问宿主机的3306端口

mysql -h 172.16.101.55 -u root -pmypna123 -P  mysql -e "status"
mysql: [Warning] Using a password on the command line interface can be insecure.
--------------
mysql  Ver 14.14 Distrib 5.7., for linux-glibc2. (x86_64) using  EditLine wrapper

Connection id:
Current database:    mysql
Current user:        root@sht-sgmhadoopnn-.telenav.cn
SSL:            Cipher in use is DHE-RSA-AES256-SHA
Current pager:        stdout
Using outfile:        ''
Using delimiter:    ;
Server version:        5.7.-log MySQL Community Server (GPL)
Protocol version:
Connection:        172.16.101.55 via TCP/IP
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    utf8
Conn.  characterset:    utf8
TCP port:
Uptime:             min  sec

Threads:   Questions:   Slow queries:   Opens:   Flush tables:   Open tables:   Queries per second avg: 0.062
--------------

容器互联

容器之间默认无法正常进行通信，我们新建一个web容器，在web容器里可以访问到另外一个容器mysql-new-container

# docker run --name web --hostname web --link mysql-new-container:db -it centos:latest /bin/bash

# docker ps -a --no-trunc
CONTAINER ID                                                       IMAGE                      COMMAND             CREATED             STATUS              PORTS                    NAMES
1bb29181e0cd5df1d34c94313e9920093bcf705626750da2d43f8067dd332281   centos:latest              "/bin/bash"          minutes ago       Up  minutes                                 web
bdc71602ee74907c8902c878b805cc28b57726b80350395fd4cd9cf69a86795d   mysql-new-container-temp   "/bin/bash"          minutes ago      Up  minutes       0.0.0.0:->/tcp   mysql-new-container,web/db

通过使用--link选项可以实现该功能，通过登录web容器查看信息

[root@web /]# cat /etc/hosts
127.0.0.1    localhost
::    localhost ip6-localhost ip6-loopback
fe00::    ip6-localnet
ff00::    ip6-mcastprefix
ff02::    ip6-allnodes
ff02::    ip6-allrouters
172.17.0.2    db mysql-new-container mysql-new-container
172.17.0.3    web

[root@web /]# env
DB_PORT=tcp://172.17.0.2:3306
DB_PORT_3306_TCP_ADDR=172.17.0.2
LANG=en_US.UTF-
HOSTNAME=web
DB_PORT_3306_TCP=tcp://172.17.0.2:3306
DB_PORT_3306_TCP_PORT=
PWD=/
HOME=/root
TERM=xterm
SHLVL=
DB_NAME=/web/db
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
DB_PORT_3306_TCP_PROTO=tcp
LESSOPEN=||/usr/bin/lesspipe.sh %s
_=/usr/bin/env

可以发现--link选项主要是向节点的hosts文件和环境变量添加被连接节点的信息