Docker工作原理

Docker是一个C/S结构的系统，Docker的守护进程运行在主机上，通过Socket从客户端访问。

DockerServer接收到DockerClient的命令就会执行。

工作原理

Docker为什么比虚拟机快？

  1. Docker具有比虚拟机更少的抽象层
  2. Docker利用的是宿主机的内核，vm需要虚拟化一个单独的内核（创建容器时，不需要重新加载一个操作系统内核，不需要进行引导）

Docker常用命令

docker version #版本信息
docker info #详细信息
docker 命令 --help # 帮助

镜像命令

docker images 查看本地所有镜像

REPOSITORY    TAG       IMAGE ID       CREATED        SIZE
hello-world   latest    feb5d9fea6a5   7 months ago   13.3kB
  • REPOSITORY 仓库原
  • TAG 仓库标签
  • IMAGE ID 镜像id
  • CREATED 镜像的创建时间
  • SIZE 大小

可选项

  • -a 显示全部
  • -f 过滤
  • -q 仅显示id

docker search 搜索命令

[root@iZ8vbioqlrpr01woefafo2Z ~]# docker search mysql
NAME                             DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
mysql                            MySQL is a widely used, open-source relation…   12483     [OK]       
mariadb                          MariaDB Server is a high performing open sou…   4806      [OK]       
mysql/mysql-server               Optimized MySQL Server Docker images. Create…   924                  [OK]
percona                          Percona Server is a fork of the MySQL relati…   575       [OK]       
phpmyadmin                       phpMyAdmin - A web interface for MySQL and M…   516       [OK]       
# ......

可选项

  • filter --filter =stars=3000(收藏数大于3000的镜像)

docker pull 下载命令

默认使用最新版，等价于docker pull xx:latest

[root@iZ8vbioqlrpr01woefafo2Z ~]# docker pull mysql
Using default tag: latest # 默认最新版本
latest: Pulling from library/mysql
# 分层下载，docker image的核心 联合文件系统
72a69066d2fe: Pull complete 
93619dbc5b36: Pull complete 
99da31dd6142: Pull complete 
626033c43d70: Pull complete 
37d5d7efb64e: Pull complete 
ac563158d721: Pull complete 
d2ba16033dad: Pull complete 
688ba7d5c01a: Pull complete 
00e060b6d11d: Pull complete 
1c04857f594f: Pull complete 
4d7cfa90e6ea: Pull complete 
e0431212d27d: Pull complete 
Digest: sha256:e9027fe4d91c0153429607251656806cc784e914937271037f7738bd5b8e7709 # 前面
Status: Downloaded newer image for mysql:latest
docker.io/library/mysql:latest  # 真实地址

固定版本

docker pull mysql:5.7

[root@iZ8vbioqlrpr01woefafo2Z ~]# docker pull mysql:5.7
5.7: Pulling from library/mysql
# 会发现前面已经存在了这就是分层下载的好处！，重复的部分不需要重新下载了
72a69066d2fe: Already exists 
93619dbc5b36: Already exists 
99da31dd6142: Already exists 
626033c43d70: Already exists 
37d5d7efb64e: Already exists 
ac563158d721: Already exists 
d2ba16033dad: Already exists 
0ceb82207cd7: Pull complete 
37f2405cae96: Pull complete 
e2482e017e53: Pull complete 
70deed891d42: Pull complete 
Digest: sha256:f2ad209efe9c67104167fc609cca6973c8422939491c9345270175a300419f94
Status: Downloaded newer image for mysql:5.7
docker.io/library/mysql:5.7

docker rmi -f + id

[root@iZ8vbioqlrpr01woefafo2Z ~]# docker images

REPOSITORY    TAG       IMAGE ID       CREATED        SIZE
mysql         5.7       c20987f18b13   4 months ago   448MB
mysql         latest    3218b38490ce   4 months ago   516MB
hello-world   latest    feb5d9fea6a5   7 months ago   13.3kB
[root@iZ8vbioqlrpr01woefafo2Z ~]# 
[root@iZ8vbioqlrpr01woefafo2Z ~]# docker rmi -f c20987f18b13
Untagged: mysql:5.7
Untagged: mysql@sha256:f2ad209efe9c67104167fc609cca6973c8422939491c9345270175a300419f94
Deleted: sha256:c20987f18b130f9d144c9828df630417e2a9523148930dc3963e9d0dab302a76
Deleted: sha256:6567396b065ee734fb2dbb80c8923324a778426dfd01969f091f1ab2d52c7989
Deleted: sha256:0910f12649d514b471f1583a16f672ab67e3d29d9833a15dc2df50dd5536e40f
Deleted: sha256:6682af2fb40555c448b84711c7302d0f86fc716bbe9c7dc7dbd739ef9d757150
Deleted: sha256:5c062c3ac20f576d24454e74781511a5f96739f289edaadf2de934d06e910b92
[root@iZ8vbioqlrpr01woefafo2Z ~]# docker images
REPOSITORY    TAG       IMAGE ID       CREATED        SIZE
mysql         latest    3218b38490ce   4 months ago   516MB
hello-world   latest    feb5d9fea6a5   7 months ago   13.3kB

docker rmi -f $(docker images -aq) 删除全部容器