Docker 基础命令讲解实例（镜像）

1.启动Docker

[root@localhost ~]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
   Active: inactive (dead)
     Docs: https://docs.docker.com
[root@localhost ~]# systemctl start docker
[root@localhost ~]# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.

2.镜像=>仓库

镜像存放在仓库，下载镜像，创建生成容器。

容器（对象，动态）

1）镜像信息查看

docker images 可以列出本地仓库存储的镜像。

实例：

[root@localhost ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               latest              c316d5a335a5        4 weeks ago         142MB

字段解释：

PEPOSITORY ---表示镜像的仓库源

TAG ---镜像的标签

IMAGE ID ---镜像ID

CREATED --- 镜像创建时间

SIZE ---镜像大小

docker images [选项] [镜像名字][:TAG]

-a 显示仓库所有镜像

-f 按条件检索镜像

-q 显示镜像ID

Flag shorthand -h has been deprecated, please use --help
Usage:    docker images [OPTIONS] [REPOSITORY[:TAG]]
List images
Options:
  -a, --all             Show all images (default hides intermediate images)
      --digests         Show digests
  -f, --filter filter   Filter output based on conditions provided
      --format string   Pretty-print images using a Go template
      --no-trunc        Don't truncate output
  -q, --quiet           Only show numeric IDs

2）获取镜像

docker pull [选项][name][:TAG@DIGEST]

镜像名字 + 版本 --不加版本默认最新版本

实例：

获取centos最新    
 centos:latest
[root@localhost ~]# docker pull centos:latest
latest: Pulling from library/centos
a1d0c7532777: Pull complete 
Digest: sha256:a27fd8080b517143cbbbab9dfb7c8571c40d67d534bbdee55bd6c473f432b177
Status: Downloaded newer image for centos:latest

docker images 查看新下载镜像

指定镜像名字
[root@localhost ~]# docker images centos
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos              latest              5d0da3dc9764        5 months ago        231MB

3）镜像查找

docker search [OPTIONS] TERM   查找仓库中      
    -f   过滤查找需要镜像

实例：

[root@localhost ~]# docker search ubuntu
NAME                             DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
ubuntu/nginx                     Nginx, a high-performance reverse proxy & we…   33                                      
ubuntu/mysql                     MySQL open source fast, stable, multi-thread…   24                                      
ubuntu/apache2                   Apache, a secure & extensible open-source HT…   23                                      
ubuntu/prometheus                Prometheus is a systems and service monitori…   23                                      
kasmweb/ubuntu-bionic-desktop    Ubuntu productivity desktop for Kasm Workspa…   18                                      
ubuntu/postgres                  PostgreSQL is an open source object-relation…   13                                      
ubuntu/squid                     Squid is a caching proxy for the Web. Long-t…   12                                      
ubuntu/bind9                     BIND 9 is a very flexible, full-featured DNS…   12                                      
ubuntu/redis                     Redis, an open source key-value store. Long-…   8                                       
ubuntu/prometheus-alertmanager   Alertmanager handles client alerts from Prom…   5                                       
ubuntu/grafana                   Grafana, a feature rich metrics dashboard & …   5                                       
ubuntu/telegraf                  Telegraf collects, processes, aggregates & w…   3                                       
circleci/ubuntu-server           This image is for internal use                  3                                       
ubuntu/memcached                 Memcached, in-memory keyvalue store for smal…   3                                       
ubuntu/cortex                    Cortex provides storage for Prometheus. Long…   2                                       
ubuntu/cassandra                 Cassandra, an open source NoSQL distributed …   1                                       
ubuntu                           Ubuntu is a Debian-based Linux operating sys…   0                   [OK]                
ubuntu-upstart                   DEPRECATED, as is Upstart (find other proces…   0                   [OK]                
neurodebian                      NeuroDebian provides neuroscience research s…   0                   [OK]                
open-liberty                     Open Liberty multi-architecture images based…   0                   [OK]                
ubuntu-debootstrap               DEPRECATED; use "ubuntu" instead                0                   [OK]                
bitnami/ubuntu-base-buildpack    Ubuntu base compilation image                   0                                       [OK]
websphere-liberty                WebSphere Liberty multi-architecture images …   0                   [OK]                
snyk/ubuntu                      A base ubuntu image for all broker clients t…   0                                       
rancher/ubuntuconsole                                                            0              

4）镜像删除。

docker rmi 可以删除不需要的镜像，如果有容器是基于这个镜像创建的，先删除容器。

Options:
-f, --force Force removal of the image
--no-prune Do not delete untagged parents

实例：

[root@localhost ~]# docker rmi nginx
Error response from daemon: conflict: unable to remove repository reference "nginx" (must force) - container eae194657981 is using its referenced image c316d5a335a5
nginx 
正在运行  有容器在使用中
[root@localhost ~]# docker rmi centos
Untagged: centos:latest
Untagged: centos@sha256:a27fd8080b517143cbbbab9dfb7c8571c40d67d534bbdee55bd6c473f432b177
Deleted: sha256:5d0da3dc976460b72c77d94c8a1ad043720b0416bfc16c52c45d4847e53fadb6
Deleted: sha256:74ddd0ec08fa43d09f32636ba91a0a3053b02cb4627c35051aff89f853606b59
删除成功

5）设置镜像标签

1. 镜像标签，用于标记镜像。利用docker tag 命令可以对本地境像添加标签，标签就是一个别名，一个镜像可以有多个标签，但只能有一个ID。

Usage: docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]

    docker tag 镜像名：原标签名 镜像名：新标签名

6）镜像的导入和导出。

 导出：就是指本地docker里的镜像文件导到centos，文件。
 导入：把导出的镜像文件回导到docker里。

导出：docker save

docker save [OPTIONS] IMAGE [IMAGE...]

docker save -o nginx.tar nginx:latest

实例：

[root@localhost ~]# docker save  -o nginx.tar nginx:latest
[root@localhost ~]# ll
total 142516
-rw-------. 1 root root      1233 Feb 22 22:44 anaconda-ks.cfg
-rw-------. 1 root root 145931776 Feb 28 19:02 nginx.tar

导入：docker load

Usage: docker load [OPTIONS]

Options:

-i, --input string Read from tar archive file, instead of STDIN

-q, --quiet Suppress the load output

[root@localhost ~]# docker load -i nginx.tar