創建鏡像

創建鏡像的方法有三種，1、基於已有的鏡像的容器創建；2、基於本地模板導入；3、基於dockerfile文件創建。
1、基於已有鏡像的容器創建：
使用docker commit命令，命令格式爲docker commit 【options】container [repostory[:tag]]

示例：

root@renkailang-K43SV:/home/renkailang# docker run -dit centos /bin/bash
fc72541bad7eb5430c28d06f6da6724bbeaa864f1e08474e97dc8b417f32ff61
root@renkailang-K43SV:/home/renkailang# docker commit fc7254 myrepo:v1
sha256:fad1b5fcac3d9efbde62cc8366e515993c3ced83b6fd7a1bfa4af65d2e3433a4

查看新提交的鏡像：

root@renkailang-K43SV:/home/renkailang# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED              SIZE
myrepo              v1                  fad1b5fcac3d        About a minute ago   200MB
centos              latest              49f7960eb7e4        6 weeks ago          200MB

2、通過本地模板導入鏡像
可以使用openvz提供的模板，通過URL在線創建：

root@renkailang-K43SV:/home/renkailang# docker import https://download.openvz.org/template/precreated/debian-7.0-x86-minimal.tar.gz  debian:v2
Downloading from https://download.openvz.org/template/precreated/debian-7.0-x86-minimal.tar.gz
sha256:62e8d3459bb271c5e3496b264f34d4baaa322b66870270cade16645425a932cfB/88.44MB

或者 ，通過本地文件導入：

root@renkailang-K43SV:/home/renkailang# ls
debian-7.0-x86-minimal.tar.gz 
root@renkailang-K43SV:/home/renkailang# docker import debian-7.0-x86-minimal.tar.gz debian:v3
sha256:33e16d28c5c9828ab9d7745ee082a4eb35fadb50487fd742252a3ed02be91181

3、保存和加載鏡像：
查看當前鏡像：

root@renkailang-K43SV:/home/renkailang# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos              v2                  1b6231b7505a        2 minutes ago       288MB

保存當前鏡像到tar文件：

root@renkailang-K43SV:/home/renkailang# docker save -o centosv3.tar centos:v2
root@renkailang-K43SV:/home/renkailang# ls
centosv3.tar  debian-7.0-x86-minimal.tar.gz

載入tar文件到鏡像：

root@renkailang-K43SV:/home/renkailang# docker load -i centosv3.tar