大家都知道，如果外界要和Docker容器进行通讯，那么除了link必须是port映射，下面先介绍下Dockerfile EXPOSE的用法，然后做一个多端口随机映射的实例吧。

格式为： 
EXPOSE PORT

下面是我的Dockerfile

<code class="hljs vala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Tomcat</span>
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Version 0.0.1</span>

<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># GET_IMAGE</span>
FROM <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.0</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.216</span>:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">5000</span>/centos

<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># MAINTAINER_INFO</span>
MAINTAINER hongxue hongxue@showjoy.com

RUN yum -y install vim
RUN yum -y install net-tools
RUN yum -y install openssh-server
RUN yum -y install wget curl

<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># PORT</span>
EXPOSE <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8080</span>
EXPOSE <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">22</span>
EXPOSE <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8009</span>
EXPOSE <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8005</span>
EXPOSE <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8443</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

我在Dockerfile中定义了 tomcat 的四个端口和ssh 22 端口，并且构建该配置档为镜像文件，镜像名为 port_list

<code class="hljs 1c has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">docker build -t port_list .
docker images <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">| grep port_list</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

构建成功后运行该 images，注意在容器运行的时候一定要加-P

<code class="hljs applescript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">docker <span class="hljs-command" style="box-sizing: border-box;">run</span> -d -<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">it</span> -P <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">--name port_list_container port_list</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

OK，Container已经running，分别映射端口为（22，8005，8009，8443，8080）映射到本机中的(32775，32776，32777，32773，32774)