一、简介

本文主要介绍如何使用docker安装centos镜像。
有了centos镜像之后，就可以在该镜像中安装一些环境，软件等等，方便复制。
一般有俩种方式安装，一种是直接拉取开源的镜像，一种是使用dockerfile定制安装。

二、拉取开源镜像安装

2.1 查询开源centos镜像

使用docker search 命令来查询开源镜像；

[root@yuanshushu ~]# docker search centos
NAME                               DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
centos                             The official build of CentOS.                   5649                [OK]
ansible/centos7-ansible            Ansible on Centos7                              125                                     [OK]
jdeathe/centos-ssh                 OpenSSH / Supervisor / EPEL/IUS/SCL Repos - …   114                                     [OK]
consol/centos-xfce-vnc             Centos container with "headless" VNC session…   100                                     [OK]
centos/mysql-57-centos7            MySQL 5.7 SQL database server                   64
imagine10255/centos6-lnmp-php56    centos6-lnmp-php56                              57                                      [OK]
tutum/centos                       Simple CentOS docker image with SSH access      44
centos/postgresql-96-centos7       PostgreSQL is an advanced Object-Relational …   39
kinogmt/centos-ssh                 CentOS with SSH                                 29                                      [OK]
pivotaldata/centos-gpdb-dev        CentOS image for GPDB development. Tag names…   10
guyton/centos6                     From official centos6 container with full up…   9                                       [OK]
drecom/centos-ruby                 centos ruby                                     6                                       [OK]
centos/tools                       Docker image that has systems administration…   4                                       [OK]
darksheer/centos                   Base Centos Image -- Updated hourly             3                                       [OK]
mamohr/centos-java                 Oracle Java 8 Docker image based on Centos 7    3                                       [OK]
pivotaldata/centos                 Base centos, freshened up a little with a Do…   3
pivotaldata/centos-mingw           Using the mingw toolchain to cross-compile t…   2
miko2u/centos6                     CentOS6 日本語環境                                   2                                       [OK]
pivotaldata/centos-gcc-toolchain   CentOS with a toolchain, but unaffiliated wi…   2
indigo/centos-maven                Vanilla CentOS 7 with Oracle Java Developmen…   1                                       [OK]
blacklabelops/centos               CentOS Base Image! Built and Updates Daily!     1                                       [OK]
mcnaughton/centos-base             centos base image                               1                                       [OK]
pivotaldata/centos7-dev            CentosOS 7 image for GPDB development           0
smartentry/centos                  centos with smartentry                          0                                       [OK]
pivotaldata/centos6.8-dev          CentosOS 6.8 image for GPDB development         0

2.2 下载官方开源镜像

下载的默认是最新的，我也不知道是不是centos7版本。。。。

[root@yuanshushu ~]# docker pull centos

查看本地镜像

[root@yuanshushu ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos              latest              0f3e07c0138f        5 weeks ago         220MB

2.3 创建容器并运行

基于镜像centos:latest镜像创建一个名称为centos-01的容器，并进入；
-t：在新容器内指定一个伪终端或终端；
-i：允许你对容器内的标准输入 (STDIN) 进行交互；
–name：为命名容器名称；
centos为源镜像名称；
/bin/bash 为进入新的容器centos-01;
注意：进入之后，@后面的名称就改为了容器id;

[root@yuanshushu ~]# docker run -it --name centos-01 centos /bin/bash
[root@8e2b1edba516 /]#

也可以使用-d命令来后台启动容器，然后使用attach进入

[root@yuanshushu ~]# docker run -itd --name centos-002 centos /bin/bash
aeb0617e6a98d9282ae4cb00ef2de38e0f172f832db5d3ac72fa7cfe680aef92
[root@yuanshushu ~]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
aeb0617e6a98        centos              "/bin/bash"         14 seconds ago      Up 13 seconds                           centos-002
[root@yuanshushu ~]# docker attach aeb0617e6a98
[root@aeb0617e6a98 /]#

此时可以查看centos-01内部文件结构，如下：

[root@8e2b1edba516 /]# ls
bin  dev  etc  home  lib  lib64  lost+found  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var

可以使用exit命令退出容器
注意此时@已经回退到宿主机上了

[root@737b37aa53df /]# exit
exit
[root@yuanshushu ~]#

查看所有的容器

[root@yuanshushu ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                        PORTS               NAMES
ab7dc6a5f4ae        centos:latest       "/bin/bash"         8 minutes ago       Exited (0) 8 minutes ago                          centos-001
8e2b1edba516        centos              "/bin/bash"         13 minutes ago      Exited (127) 10 minutes ago                       centos-01