（十三）镜像小结
这一部分我们首先讨论了镜像的分层结构，然后学习了如何构建镜像，最后实践使用 Docker Hub 和本地 registry。
镜像常用命令：
images 显示镜像列表
history 显示镜像构建历史
commit 从容器创建新镜像
build 从 Dockerfile 构建镜像
tag 给镜像打 tag
pull 从 registry 下载镜像
push 将 镜像 上传到 registry
rmi 删除 Docker host 中的镜像
search 搜索 Docker Hub 中的镜像
（1）rmi
rmi 只能删除 host 上的镜像，不会删除 registry 的镜像。如果一个镜像对应了多个 tag，只有当最后一个 tag 被删除时，镜像才被真正删除。例如 host 中 httpd 镜像有两个 tag：
root@cuiyongchao:/dockerfile# docker images httpd
REPOSITORY TAG IMAGE ID CREATED SIZE
httpd latest 3dd970e6b110 2 weeks ago 138MB
httpd v1 3dd970e6b110 2 weeks ago 138MB
root@cuiyongchao:/dockerfile#
删除其中 debian:latest 只是删除了 latest tag，镜像本身没有删除。
root@cuiyongchao:/dockerfile# docker rmi httpd:latest
Untagged: httpd:latest
root@cuiyongchao:/dockerfile# docker images httpd
REPOSITORY TAG IMAGE ID CREATED SIZE
httpd v1 3dd970e6b110 2 weeks ago 138MB
root@cuiyongchao:/dockerfile#
只有当 httpd: v1 也被删除时，整个镜像才会被删除。
root@cuiyongchao:/dockerfile# docker rmi httpd:v1
Untagged: httpd:v1
Untagged: httpd@sha256:b82fb56847fcbcca9f8f162a3232acb4a302af96b1b2af1c4c3ac45ef0c9b968
root@cuiyongchao:/dockerfile# docker images httpd
REPOSITORY TAG IMAGE ID CREATED SIZE
root@cuiyongchao:/dockerfile#
（2）search
search 让我们无需打开浏览器，在命令行中就可以搜索 Docker Hub 中的镜像。
root@cuiyongchao:/dockerfile# docker search httpd
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
httpd The Apache HTTP Server Project 3226 [OK]
centos/httpd-24-centos7 Platform for running Apache httpd 2.4 or bui… 36
centos/httpd 32 [OK]
arm32v7/httpd The Apache HTTP Server Project 9
arm64v8/httpd The Apache HTTP Server Project 5
polinux/httpd-php Apache with PHP in Docker (Supervisor, CentO… 4 [OK]
salim1983hoop/httpd24 Dockerfile running apache config 2 [OK]
lead4good/httpd-fpm httpd server which connects via fcgi proxy h… 1 [OK]
solsson/httpd-openidc mod_auth_openidc on official httpd image, ve… 1 [OK]
jonathanheilmann/httpd-alpine-rewrite httpd:alpine with enabled mod_rewrite 1 [OK]
publici/httpd httpd:latest 1 [OK]
dariko/httpd-rproxy-ldap Apache httpd reverse proxy with LDAP authent… 1 [OK]
clearlinux/httpd httpd HyperText Transfer Protocol (HTTP) ser… 1
appertly/httpd Customized Apache HTTPD that uses a PHP-FPM … 0 [OK]
interlutions/httpd httpd docker image with debian-based config … 0 [OK]
e2eteam/httpd 0
amd64/httpd The Apache HTTP Server Project 0
manasip/httpd 0
trollin/httpd 0
hypoport/httpd-cgi httpd-cgi 0 [OK]
manageiq/httpd_configmap_generator Httpd Configmap Generator 0 [OK]
itsziget/httpd24 Extended HTTPD Docker image based on the off… 0 [OK]
manageiq/httpd Container with httpd, built on CentOS for Ma… 0 [OK]
alvistack/httpd Docker Image Packaging for Apache 0 [OK]
dockerpinata/httpd 0
root@cuiyongchao:/dockerfile#
