当运行容器时，使用的镜像如果在本地中不存在，docker 就会自动从 docker 镜像仓库中下载，默认是从 Docker Hub 公共镜像源下载。我们可以从 Docker Hub 网站来搜索镜像，Docker Hub 网址为： https://hub.docker.com/，我们也可以使用 docker search 命令来搜索镜像。比如我们需要一个centos的镜像来作为我们的服务器。我们可以通过 docker search 命令搜索 centos 来寻找适合我们的镜像。
搜索镜像：docker search
选镜像的建议： 1.优先考虑官方 2.stars数量多
[root@docker01 ~]# docker search centos
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
centos The official build of CentOS. 5461 [OK]
ansible/centos7-ansible Ansible on Centos7 122 [OK]
jdeathe/centos-ssh CentOS-6 6.10 x86_64 / CentOS-7 7.6.1810 x86… 110 [OK]
consol/centos-xfce-vnc Centos container with "headless" VNC session… 93 [OK]
centos/mysql-57-centos7 MySQL 5.7 SQL database server 59
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 … 38
kinogmt/centos-ssh CentOS with SSH 28 [OK]
centos/php-56-centos7 Platform for building and running PHP 5.6 ap… 21
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]
mamohr/centos-java Oracle Java 8 Docker image based on Centos 7 3 [OK]
darksheer/centos Base Centos Image -- Updated hourly 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
mcnaughton/centos-base centos base image 1 [OK]
indigo/centos-maven Vanilla CentOS 7 with Oracle Java Developmen… 1 [OK]
blacklabelops/centos CentOS Base Image! Built and Updates Daily! 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
[root@docker01 ~]#
= Name：镜像名称，
= DESCRIPTION：镜像的描述
= STARS：别星标的数量，数量越大说明受人认可度越高
= OFFICIAL：是否为官方产品
= AUTOMATED：是否为自动化构建
获取镜像: docker pull（push）
（因为墙的原因，需要镜像加速，否则连接超时，无法下载）
镜像加速器：阿里云加速器，daocloud加速器，中科大加速器，Docker 中国官方镜像加速：https://registry.docker-cn.com
docker pull centos:6.8（没有指定版本，默认会下载最新版）
docker pull daocloud.io/huangzhichong/alpine-cn:latest
[root@docker01 ~]# docker pull centos:6.8
6.8: Pulling from library/centos
7ce0cebb9dca: Pull complete
Digest: sha256:39abd0c8e375de6fb7334d42ec2a46643f34cbc1bbaf37e2b484065f05eaa7a2
Status: Downloaded newer image for centos:6.8
[root@docker01 ~]# docker pull centos
Using default tag: latest
latest: Pulling from library/centos
8ba884070f61: Pull complete
Digest: sha256:a799dd8a2ded4a83484bbae769d97655392b3f86533ceb7dd96bbac929809f3c
Status: Downloaded newer image for centos:latest
[root@docker01 ~]#
扩展：查询docker镜像所有版本https://hub.docker.com/r/library/
国内是所有镜像网站：https://www.douban.com/note/517555410/
私有仓库的镜像名称都较长（网站地址，用户名，版本名等）
docker镜像其他操作
1.查看镜像：docker images（等效命令：docker image ls）
[root@docker01 ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest 98ebf73aba75 5 days ago 109MB
centos 6.8 82f3b5f3c58f 4 months ago 195MB
centos latest 9f38484d220f 4 months ago 202MB
[root@docker01 ~]#
[root@docker01 ~]# docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest 98ebf73aba75 5 days ago 109MB
centos 6.8 82f3b5f3c58f 4 months ago 195MB
centos latest 9f38484d220f 4 months ago 202MB
[root@docker01 ~]#
REPOSITORY：镜像名字
TAG：标签（可自定义）
IMAGE ID：镜像ID（唯一）
CREATED：创建时间
SIZE：镜像大小
2.删除镜像 docker rmi 等效命令（docker image rm） 例子：docker image rm centos:latest
[root@docker01 ~]# docker rmi centos:6
Untagged: centos:6
Untagged: centos@sha256:dec8f471302de43f4cfcf82f56d99a5227b5ea1aa6d02fa56344986e1f4610e7
Deleted: sha256:d0957ffdf8a2ea8c8925903862b65a1b6850dbb019f88d45e927d3d5a3fa0c31
Deleted: sha256:af6bf1987c2eb07d73f33836b0d8fd825d7c785273526b077e46780e8b4b2ae9
[root@docker01 ~]#
[root@docker01 ~]# docker image rm centos:latest
Untagged: centos:latest
Untagged: centos@sha256:a799dd8a2ded4a83484bbae769d97655392b3f86533ceb7dd96bbac929809f3c
Deleted: sha256:9f38484d220fa527b1fb19747638497179500a1bed8bf0498eb788229229e6e1
Deleted: sha256:d69483a6face4499acb974449d1303591fcbb5cdce5420f36f8a6607bda11854
[root@docker01 ~]#
= docker rmi centos:6，需要在所删容器后加上标签，否则（docker rmi centos）默认删掉最新版
3.导出镜像 docker save 等效命令（docker image save） 例子：docker image save centos > docker-centos7.4.tar.gz
[root@docker01 ~]# docker image save centos:6.8 >docker_centos6.8.tar.gz
[root@docker01 ~]# ll
total 197480
-rw-------. 1 root root 1757 Nov 27 2018 anaconda-ks.cfg
-rw-r--r-- 1 root root 202213376 Jul 23 09:36 docker_centos6.8.tar.gz
[root@docker01 ~]#
4.导入镜像 docker load 等效命令（docker image load）例子：docker image load -i docker-centos7.4.tar.gz
[root@docker01 ~]# docker image load -i docker_centos6.8.tar.gz
ad337ac82f03: Loading layer [==================================================>] 202.2MB/202.2MB
Loaded image: centos:6.8
-i：指定导入的镜像
5.docker其他命令，通过docker image可查看其他docker命令
[root@docker01 ~]# docker image
Usage: docker image COMMAND
Manage images
Commands:
build Build an image from a Dockerfile
history Show the history of an image
import Import the contents from a tarball to create a filesystem image
inspect Display detailed information on one or more images
load Load an image from a tar archive or STDIN
ls List images
prune Remove unused images
pull Pull an image or a repository from a registry
push Push an image or a repository to a registry
rm Remove one or more images
save Save one or more images to a tar archive (streamed to STDOUT by default)
tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
Run 'docker image COMMAND --help' for more information on a command.
[root@docker01 ~]#
= build：构建镜像，可手动创建镜像
= history：查看构建镜像的历史记录
= import：导入镜像（已弃用）
= inspect：查看镜像详情信息，属性
= load：导入镜像
= ls：查看镜像列表
= prune：删除镜像（已弃用）
= pull：下载镜像
= push：上传镜像
= rm：删除镜像
= save：导出镜像
= tag：给镜像取别名
