简介：介绍两种方式创建image：从Dockerfile 生成新的image，使用docker build命令；在原有image上改进生成新的image，直接pull image，install and commit；
方式一：在原有image上通过Dockerfile生成新的image
eg:在ubuntu 14.04 版本上添加ruby 功能
第一步. 编辑Dockerfile
root@ubuntu-daisy:~# mkdir daisy_dockerbuild
root@ubuntu-daisy:~# ls
bamboo daisy_dockerbuild index.html sinatra
root@ubuntu-daisy:~# cd daisy_dockerbuild/
root@ubuntu-daisy:~/daisy_dockerbuild# touch Dockerfile
root@ubuntu-daisy:~/daisy_dockerbuild# ls Dockerfile
打开Dockfile 编辑内容：
root@ubuntu-daisy:~/daisy_dockerbuild# vim Dockerfile
root@ubuntu-daisy:~/daisy_dockerbuild# cat Dockerfile FROM ubuntu:14.04 RUN export http_proxy=http://proxy-prc.webl.com:911 && export https_proxy=https://proxy-prc.web.com:911 && apt-get update && apt-get install -y ruby ruby-dev 开始build image root@ubuntu-daisy:~/daisy_dockerbuild# docker build -t ubuntu . Sending build context to Docker daemon 2.048 kB Step 1 : FROM ubuntu:14.04 ---> 4a725d3b3b1c Step 2 : RUN export http_proxy=http://proxy-prc.intel.com:911 && export https_proxy=https://proxy-prc.intel.com:911 && apt-get update && apt-get install -y ruby ruby- dev ---> Using cache ---> 6b2695fa32bf Successfully built 6b2695fa32bf
查看已经建立成功
root@ubuntu-daisy:~/daisy_dockerbuild# docker images REPOSITORY TAG IMAGE ID CREATED SIZE ubuntu latest 6b2695fa32bf About an hour ago 306.8 MB
方式二：在原有image上改进生成新的image
首先查找你需要的image
root@ubuntu-daisy:~# docker search sinatra NAME DESCRIPTION STARS OFFICIAL AUTOMATED hwada/sinatra sinatra for hands on of aws-docker-fluentd-s3 0 [OK] kerona/sinatra 0 [OK] root@ubuntu-daisy:~# docker pull kerona/sinatra
以kerona/sinatra 容器为基础，再建一个container root@ubuntu-daisy:~# docker run -t -i kerona/sinatra /bin/bash
root@7199eb77c75c:/# export http_proxy=http://proxy-prc.web.com:911 // 设置代理 root@7199eb77c75c:/# export https_proxy=https://proxy-prc.web.com:911
root@7199eb77c75c:/# apt-get install -y ruby2.0-dev Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: ruby2.0-dev 0 upgraded, 1 newly installed, 0 to remove and 3 not upgraded. Need to get 908 kB of archives. After this operation, 4323 kB of additional disk space will be used. Get:1 http://archive.ubuntu.com/ubuntu/ trusty-updates/main ruby2.0-dev amd64 2.0.0.484-1ubuntu2.2 [908 kB] Fetched 908 kB in 2s (306 kB/s) Selecting previously unselected package ruby2.0-dev:amd64. (Reading database ... 16609 files and directories currently installed.) Preparing to unpack .../ruby2.0-dev_2.0.0.484-1ubuntu2.2_amd64.deb ... Unpacking ruby2.0-dev:amd64 (2.0.0.484-1ubuntu2.2) ... Setting up ruby2.0-dev:amd64 (2.0.0.484-1ubuntu2.2) ...
root@ubuntu-daisy:~# docker commit -m "Added ruby" -a "daisy" 62b83f189561 daisy/sinatra:v2 sha256:203b756a3edfd0f617a8e41dfefe3f411c41b4e3388b07cf012fdbe4a8b3ebb2
查看已经生成了自己的image root@ubuntu-daisy:~# docker images REPOSITORY TAG IMAGE ID CREATED SIZE daisy/sinatra v2 203b756a3edf 16 seconds ago 316.4 MB
两种方法，其中方法一更方便使用，也便于team内共享。在创建own image 时，我需要每次都设置http是因为公司网络是代理的缘故，正常情况不用设置就能连上网。
