Docker详解：从基本概念到常用命令-优快云博客

本文链接：https://blog.youkuaiyun.com/NeaWalke/article/details/121654301

本文详细介绍了Docker容器的发展历程，包括lxc、libcontainer到runC的变化，以及开放容器倡议（OCI）和开放容器格式（OCF）的标准。Docker提供了镜像仓库，如Docker Hub，用于存储和分享镜像。文章还阐述了镜像与容器之间的关系，以及如何在CentOS上安装和配置Docker，包括设置Docker加速器。最后，列举了多个Docker常用命令，如创建、运行、管理容器和镜像，以及查看Docker信息等。

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docker

docker中的容器：

lxc --> libcontainer --> runC

OCI&OCF

OCI
开放容器倡议

由Linux基金会主导于2015年6月创立
旨在围绕容器格式和运行时制定一个开放的工业化标准
contains two specifications
the Runtime Specification（runtime-spec）
the Image Specification（image-spec）

OCF
开放容器格式

runC is a CLI tool for spawning and running containers according to the OCI specification

容器作为 runC 的子进程启动，可以嵌入到各种其他系统中，而无需运行守护进程
runC 建立在 libcontainer 之上，同样的容器技术为数百万个 Docker 引擎安装提供支持

docker提供了一个专门容纳容器镜像的站点：https://hub.docker.com/.

docker镜像与镜像仓库

镜像仓库名字为registry，在docker中仓库的名字是以应用的名称取名的。

镜像是静态的，而容器是动态的，容器有其生命周期，镜像与容器的关系类似于程序与进程的关系。镜像类似于文件系统中的程序文件，而容器则类似于将一个程序运行起来的状态，也即进程。所以容器是可以删除的，容器被删除后其镜像是不会被删除的。

在这里插入图片描述

docker对线

当您使用 docker 时，您正在创建和使用图像、容器、网络、卷、插件和其他对象。

IMAGES

图像是一个只读模板，其中包含创建 docker 容器的说明。
通常，一个图像基于另一个图像，并带有一些额外的自定义。
您可以创建自己的映像，也可以仅使用其他人创建并在注册表中发布的映像。

CONTAINERS

容器是图像的可运行实例。
您可以使用 docker API 或 CLI 创建、运行、停止、移动或删除容器。
您可以将容器连接到一个或多个网络，为其附加存储，甚至可以根据其当前状态创建新映像

docker的安装

[root@localhost ~]# cd /etc/yum.repos.d/
[root@localhost yum.repos.d]# curl -o docker-ce.repo https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/centos/docker-ce.repo
[root@localhost yum.repos.d]# sed -i 's@https://download.docker.com@https://mirrors.tuna.tsinghua.edu.cn/docker-ce@g' docker-ce.repo

[root@localhost ~]# yum -y install docker-ce

docker加速

docker-ce的配置文件是/etc/docker/daemon.json，此文件默认不存在，需要我们手动创建并进行配置，而docker的加速就是通过配置此文件来实现的。

docker的加速有多种方式：

docker cn
中国科技大学加速器
阿里云加速器（需要通过阿里云开发者平台注册帐号，免费使用个人私有的加速器）

[root@localhost ~]# systemctl enable --now docker
Created symlink /etc/systemd/system/multi-user.target.wants/docker.service → /usr/lib/systemd/system/docker.service.

[root@localhost ~]# cat /etc/docker/daemon.json 
{
    "registry-mirrors": ["https://docker.mirrors.ustc.edu.cn/"]
}

[root@localhost ~]# systemctl restart docker

[root@localhost ~]# docker info
···
 Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://docker.mirrors.ustc.edu.cn/
 Live Restore Enabled: false

docker常用命令

docker 查看Docker基本信息、命令列表

[root@localhost ~]# docker

Usage:  docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Options:
      --config string      Location of client config files (default "/root/.docker")
  -c, --context string     Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var and default
                           context set with "docker context use")
  -D, --debug              Enable debug mode
  -H, --host list          Daemon socket(s) to connect to
  -l, --log-level string   Set the logging level ("debug"|"info"|"warn"|"error"|"fatal") (default "info")
      --tls                Use TLS; implied by --tlsverify
      --tlscacert string   Trust certs signed only by this CA (default "/root/.docker/ca.pem")
      --tlscert string     Path to TLS certificate file (default "/root/.docker/cert.pem")
      --tlskey string      Path to TLS key file (default "/root/.docker/key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit

Management Commands:
  app*        Docker App (Docker Inc., v0.9.1-beta3)
  builder     Manage builds
  buildx*     Build with BuildKit (Docker Inc., v0.6.3-docker)
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  image       Manage images
  manifest    Manage Docker image manifests and manifest lists
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  scan*       Docker Scan (Docker Inc., v0.9.0)
  secret      Manage Docker secrets
  service     Manage services
  stack       Manage Docker stacks
  swarm       Manage Swarm
  system      Manage Docker
  trust       Manage trust on Docker images
  volume      Manage volumes

Commands:
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit codes

Run 'docker COMMAND --help' for more information on a command.

To get more help with docker, check out our guides at https://docs.docker.com/go/guides/

docker info查看Docker信息

[root@localhost ~]# docker info
Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Build with BuildKit (Docker Inc., v0.6.3-docker)
  scan: Docker Scan (Docker Inc., v0.9.0)
······

docker version查看Docker版本信息

[root@localhost ~]# docker version
Client: Docker Engine - Community
 Version:           20.10.11
 API version:       1.41
 Go version:        go1.16.9
 Git commit:        dea9396
 Built:             Thu Nov 18 00:36:58 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.11
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.9
  Git commit:       847da18
  Built:            Thu Nov 18 00:35:20 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.12
  GitCommit:        7b11cfaabd73bb80907dd23182b9347b4245eb5d
 runc:
  Version:          1.0.2
  GitCommit:        v1.0.2-0-g52b36a2
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker search搜索镜像镜像仓库.

[root@localhost ~]# docker search nginx
NAME                              DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
nginx                             Official build of Nginx.                        15893     [OK]       
jwilder/nginx-proxy               Automated Nginx reverse proxy for docker con…   2098                 [OK]
richarvey/nginx-php-fpm           Container running Nginx + PHP-FPM capable of…   819                  [OK]
jc21/nginx-proxy-manager          Docker container for managing Nginx proxy ho…   285                  
······

docker pull拉取镜像

[root@localhost ~]# docker pull nginx
Using default tag: latest
latest: Pulling from library/nginx
eff15d958d66: Pull complete 
1e5351450a59: Pull complete 
2df63e6ce2be: Pull complete 
9171c7ae368c: Pull complete 
020f975acd28: Pull complete 
266f639b35ad: Pull complete 
Digest: sha256:097c3a0913d7e3a5b01b6c685a60c03632fc7a2b50bc8e35bcaa3691d788226e
Status: Downloaded newer image for nginx:latest
docker.io/library/nginx:latest

docker images查看已安装的镜像

[root@localhost ~]# docker images
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
nginx        latest    ea335eea17ab   2 weeks ago   141MB

docker run 运行一个容器，自动拉取镜像、自动创建容器、自动运行

docker run [options] image [command]
options:
  -a stdin: 指定标准输入输出内容类型，可选stdin/stdout/stderr
  -i: 以交互模式运行容器，通常与-t同时使用
  -t: 为容器重新分配一个伪输入终端
  -d: 运行一个容器，在后台运行或者打印容器id
  -P: 随机端口映射，容器内部端口随机映射到主机的端口
  -p: 指定端口映射，例：宿主机端口:容器端口
  --name: 为容器指定一个名称
  --dns: 指定容器使用的DNS服务器
  -v: 绑定一个卷


[root@localhost ~]# docker run -itd --name nginx1 nginx
0fbb5c053e4be1f8bf06b2ad544c8e22de9009d2949bd5381d3c3ac9188a3377

docker create创建一个新容器，不运行

[root@localhost ~]# docker create --name nginx2 nginx
b80f60f520bf46cea6fd5d0c6c0df97dc28a69a60996148fa508c182a8806140

docker ps列出正在运行的容器docker ps -a这样可列出所有容器

[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED             STATUS             PORTS     NAMES
0fbb5c053e4b   nginx     "/docker-entrypoint.…"   About an hour ago   Up About an hour   80/tcp    nginx1

[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND                  CREATED             STATUS                         PORTS     NAMES
b80f60f520bf   nginx     "/docker-entrypoint.…"   15 minutes ago      Created                                  nginx2
0fbb5c053e4b   nginx     "/docker-entrypoint.…"   About an hour ago   Up About an hour               80/tcp    nginx1

docker start开启一个或多个已经关闭的容器

[root@localhost ~]# docker start b80f60f520bf
b80f60f520bf
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED             STATUS             PORTS     NAMES
b80f60f520bf   nginx     "/docker-entrypoint.…"   16 minutes ago      Up 5 seconds       80/tcp    nginx2
0fbb5c053e4b   nginx     "/docker-entrypoint.…"   About an hour ago   Up About an hour   80/tcp    nginx1

docker stop 停止容器

[root@localhost ~]# docker stop 0fbb5c053e4b
0fbb5c053e4b
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS         PORTS     NAMES
b80f60f520bf   nginx     "/docker-entrypoint.…"   18 minutes ago   Up 2 minutes   80/tcp    nginx2

docker kill杀掉容器

[root@localhost ~]# docker kill b80f60f520bf
b80f60f520bf
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
[root@localhost ~]#

docker attach连接到正在运行的容器上

[root@localhost ~]# docker attach nginx1

docker exec进入容器

[root@localhost ~]# docker exec -it /bin/bash nginx1
Error: No such container: /bin/bash
[root@localhost ~]# docker exec -it nginx1 /bin/bash
root@0fbb5c053e4b:/# ls
bin   dev		   docker-entrypoint.sh  home  lib64  mnt  proc  run   srv  tmp  var
boot  docker-entrypoint.d  etc			 lib   media  opt  root  sbin  sys  usr

docker logs查看容器日志

[root@localhost ~]# docker logs nginx1
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
······

docker rm删除容器

[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND                  CREATED             STATUS                        PORTS     NAMES
b80f60f520bf   nginx     "/docker-entrypoint.…"   About an hour ago   Exited (137) 10 minutes ago             nginx2
0fbb5c053e4b   nginx     "/docker-entrypoint.…"   2 hours ago         Exited (0) 44 minutes ago               nginx1
9bf5e5ab90f6   nginx     "/docker-entrypoint.…"   2 hours ago         Exited (0) 2 hours ago                  angry_booth
[root@localhost ~]# docker rm 9bf5e5ab90f6
9bf5e5ab90f6
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND                  CREATED             STATUS                        PORTS     NAMES
b80f60f520bf   nginx     "/docker-entrypoint.…"   About an hour ago   Exited (137) 10 minutes ago             nginx2
0fbb5c053e4b   nginx     "/docker-entrypoint.…"   2 hours ago         Exited (0) 45 minutes ago               nginx1

docker rmi删除镜像

# 当容器正在运行镜像不能删除
[root@localhost ~]# docker rmi -f nginx
Untagged: nginx:latest
Untagged: nginx@sha256:097c3a0913d7e3a5b01b6c685a60c03632fc7a2b50bc8e35bcaa3691d788226e
[root@localhost ~]# docker images
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
<none>       <none>    ea335eea17ab   2 weeks ago   141MB
[root@localhost ~]#