Docker课堂实验手册(二)

在上一篇文章中，练习在 Ubuntu Server 18.04 中安装了 Docker, 在本次实验中，主要让大家练习 Docker 的一些常用命令。

使用 info 命令查看配置信息

执行:

1	docker info

系统显示:

Client:
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 19.03.1
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk s                                                                                                                                                             yslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 894b81a4b802e4eb2a91d1ce216b8817763c29fb
 runc version: 425e105d5a03fabd737a126ad93d62a9eeede87f
 init version: fec3683
 Security Options:
  apparmor
  seccomp
   Profile: default
 Kernel Version: 4.15.0-58-generic
 Operating System: Ubuntu 18.04.3 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 1.924GiB
 Name: kmaster
 ID: MMAL:HBWC:OL6A:KFVG:ZJ5U:VLA6:G36V:X5C3:G2AJ:5GDE:FL7R:RHXO
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: No swap limit support

可以看到，现在使用的官方的镜像源（Registry项），但官方的镜像源在国内访问速度比较慢，所以我们先换成国内的镜像源

编辑或新增（如果不存在）/etc/docker/daemon.json 文件

1	sudo vi /etc/docker/daemon.json

将以下内容加入到文件中:

{
    "registry-mirrors": [
        "https://registry.docker-cn.com"
    ]
}

保存以后，需要重启 docker 服务，

1	sudo systemctl restart docker

再执行 info 命令，就可以看到刚加入的镜像源网站了。

sudo info

系统输出:

...
Registry Mirrors:
  https://registry.docker-cn.com/
...

参考当前镜像(image)列表

执行 images 命令，查看当前以下载的镜像列表

1	docker images

系统显示:

1	REPOSITORY TAG IMAGE ID CREATED SIZE

可以看到，当前还没有将任何镜像下载到本地。

在镜像源中查找镜像

在官方镜像源 - docker hub 中，有全球docker使用者自作的各种镜像，可以通过 docker search 命令查找符合条件的镜像。命令格式如下:

1	docker search <关键字>

比如要查找 alpine 相关的镜像，就可以执行:

1	docker search alpine

如果网络正常，系统会显示:

NAME                                   DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
alpine                                 A minimal Docker image based on Alpine Linux…   5613                [OK]                
mhart/alpine-node                      Minimal Node.js built on Alpine Linux           440                                     
anapsix/alpine-java                    Oracle Java 8 (and 7) with GLIBC 2.28 over A…   421                                     [OK]
frolvlad/alpine-glibc                  Alpine Docker image with glibc (~12MB)          210                                     [OK]
gliderlabs/alpine                      Image based on Alpine Linux will help you wi…   180                                     
mvertes/alpine-mongo                   light MongoDB container                         105                                     [OK]
alpine/git                             A  simple git container running in alpine li…   98                                      [OK]
yobasystems/alpine-mariadb             MariaDB running on Alpine Linux [docker] [am…   48                                      [OK]
kiasaki/alpine-postgres                PostgreSQL docker image based on Alpine Linux   44                                      [OK]
alpine/socat                           Run socat command in alpine container           36                                      [OK]
davidcaste/alpine-tomcat               Apache Tomcat 7/8 using Oracle Java 7/8 with…   36                                      [OK]
zzrot/alpine-caddy                     Caddy Server Docker Container running on Alp…   35                                      [OK]
easypi/alpine-arm                      AlpineLinux for RaspberryPi                     32                                      
byrnedo/alpine-curl                    Alpine linux with curl installed and set as …   26                                      [OK]
jfloff/alpine-python                   A small, more complete, Python Docker image …   26                                      [OK]
hermsi/alpine-sshd                     Dockerize your OpenSSH-server with rsync and…   24                                      [OK]
etopian/alpine-php-wordpress           Alpine WordPress Nginx PHP-FPM WP-CLI           21                                      [OK]
hermsi/alpine-fpm-php                  Dockerize your FPM PHP 7.4 upon a lightweigh…   19                                      [OK]
bashell/alpine-bash                    Alpine Linux with /bin/bash as a default she…   14                                      [OK]
zenika/alpine-chrome                   Chrome running in headless mode in a tiny Al…   13                                      [OK]
davidcaste/alpine-java-unlimited-jce   Oracle Java 8 (and 7) with GLIBC 2.21 over A…   13                                      [OK]
tenstartups/alpine                     Alpine linux base docker image with useful p…   9                                       [OK]
spotify/alpine                         Alpine image with `bash` and `curl`.            9                                       [OK]
rawmind/alpine-traefik                 This image is the traefik base. It comes fro…   5                                       [OK]
hermsi/alpine-varnish                  Dockerize Varnish upon a lightweight alpine-…   1                                       [OK]

可以看到返回的信息中包括了: 镜像名称，描述，是否官方自作等信息。

从像源中拉取镜像

要从镜像源中将自定的镜像拉取到本地，可以执行 pull 命令:

1	docker pull <镜像名>[:标签]

标签默认为: latest

我们练习拉取 search 命令查询的的官方 alpine 镜像，则执行:

1	docker pull alpine

系统显示:

Using default tag: latest
latest: Pulling from library/alpine
9d48c3bd43c5: Pull complete 
Digest: sha256:72c42ed48c3a2db31b7dafe17d275b634664a708d901ec9fd57b1529280f01fb
Status: Downloaded newer image for alpine:latest
docker.io/library/alpine:latest

执行 images 命令，可以查看已经拉取到本地的镜像

1	docker images

系统显示

1 2	REPOSITORY TAG IMAGE ID CREATED SIZE alpine latest 961769676411 2 weeks ago 5.58MB