仓库是集中存放镜像的地方

例如：
搭建的私有仓库地址：
192.168.89.200/ubuntu
192.168.89.200/centos

ip地址是注册服务器地址，ubuntu是仓库名
同一个注册服务器地址可以有多个不同的仓库，每个仓库又有不同的镜像

2、仓库又分为公有仓库和私有仓库

3、命令行登录docker官方维护的公有仓库（）
https://hub.docker.com/
前提是您必须提前注册有账户名和密码


root@docker-test:~# docker login
Username (tantianran): tantianran    #输入用户名和密码
WARNING: login credentials saved in /root/.dockercfg.    #这个文件是保存用户名和密码，密码是加密后的
Login Succeeded
root@docker-test:~#


4、登录之后，就可以非常方便的用docker search命令来搜索官方仓库中的镜像

5、例如搜索包含centos关键字的所有镜像
root@docker-test:~# docker search centos
NAME                           DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
centos                         The official build of CentOS.                   3562      [OK]       
jdeathe/centos-ssh             CentOS-6 6.9 x86_64 / CentOS-7 7.3.1611 x8...   81                   [OK]
tutum/centos                   Simple CentOS docker p_w_picpath with SSH access      33                   
kinogmt/centos-ssh             CentOS with SSH                                 16                   [OK]
centos/postgresql-94-centos7   PostgreSQL 9.4 SQL database server              11                   
centos/mysql-57-centos7        MySQL 5.7 SQL database server                   8                    
centos/php-56-centos7          PHP 5.6 platform for building and running ...   7                    
centos/python-35-centos7       Python 3.5 platform for building and runni...   5                    
centos/mongodb-26-centos7      MongoDB 2.6 NoSQL database server               4                    
centos/mysql-56-centos7        MySQL 5.6 SQL database server                   4                    
darksheer/centos               Base Centos Image -- Updated hourly             3                    [OK]
centos/php-70-centos7          PHP 7.0 platform for building and running ...   3                    
centos/redis                   Redis built for CentOS                          3                    [OK]
centos/ruby-23-centos7         Ruby 2.3 platform for building and running...   3                    
centos/python-27-centos7       Python 2.7 platform for building and runni...   2                    
centos/nginx-18-centos7        Nginx 1.8 server and a reverse proxy serve...   2                    
centos/python-34-centos7       Python 3.4 platform for building and runni...   2                    
centos/mongodb-32-centos7      MongoDB 3.2 NoSQL database server               2                    
centos/httpd-24-centos7        Apache HTTP 2.4 Server                          2                    
centos/ruby-22-centos7         Ruby 2.2 platform for building and running...   1                    
centos/nodejs-4-centos7        NodeJS 4 platform for building and running...   1                    
blacklabelops/centos           CentOS Base Image! Built and Updates Daily!     1                    [OK]
smartentry/centos              centos with smartentry                          0                    [OK]
centos/mariadb-101-centos7     MariaDB 10.1 SQL Database Server Docker p_w_picpath   0                    
pivotaldata/centos             Base centos, freshened up a little with a ...   0                    
root@docker-test:~#

注意：
官方镜像资源分为两类
1、单个名字命名的（例如centos）,是属于基础或根镜像，一般都是官方维护的镜像
2、命令方式为：tutum/centos 这种镜像是由dockerhub用户tutum创建并维护的

docker pool是国内专业的docker技术社区
地址：http://dockerpool.com