1. Dockerfile : 

    * dockerfile 是一个包含创建所有命令的文本文件，使用docker build 根据dockerfile命令创建新的镜像
* FROM tomcat  # 参考的基础镜像
* MAINTAINER  #标识镜像创建者
* 执行命令
      * RUN rm -f  /usr/local/tomcat/webapps/ROOT/index.jsp
      * RUN echo "welcome to tomcat!" >/usr/local/tomcat/webapps/ROOT/index.html

  2. 构建镜像：跟进dockerfile 文件自动构建镜像

     * docker build -f Dockerfile当前路径 -t xianwei/tomcat:v2 .
 *exp: $ docker build -f dockerfile -t xianwei/tomcat:v2 .
 * [python@localhost ~]$ sudo docker build -f /dockerfile -t xianwei/tomcat:v2 .
      Sending build context to Docker daemon  196.6MB
      Step 1/4 : FROM tomcat
        ---> ef802ca71927
        Step 2/4 : MAINTAINER Eric
         ---> Running in 328055e1575c
        Removing intermediate container 328055e1575c
        ---> 35ebde183840
        Step 3/4 : RUN rm -f /usr/local/tomcat/webapps/ROOT/index.jsp
        ---> Running in 29be0a87fdbc
        Removing intermediate container 29be0a87fdbc
         ---> 567478df2a70
        Step 4/4 : RUN echo "welcome to tomcat!"        >/usr/local/tomcat/webapps/ROOT/index.html
         ---> Running in c55851466c73
         Removing intermediate container c55851466c73
          ---> 04819a1dbce5
           Successfully built 04819a1dbce5
           Successfully tagged xianwei/tomcat:v2

3.使用新镜像运行容器

        $ sudo docker run --name v2 -p 9999:8080 -d 04819a1dbce5

4.查看容器元信息

$ sudo docker inspect tomcat:v3