Docker实战

前言

Docker 是一个开源的、C/S 架构的应用容器引擎，是 PaaS 提供商 dotCloud 基于 libContainer 推出的，它基于 Go 语言并遵从 Apache 2.0 开源协议。

应用场景

加速本地开发。通过Docker能够快速搭建好开发和运行环境，并且该环境可以直接传递给测试和产品部署。

• 自动打包和部署应用。
• 创建轻量、私有的PaaS环境。
• 自动化测试和持续集成/部署。
• 部署并扩展Web应用、数据库和后端服务器。
• 创建安全沙盒。
• 轻量级的桌面虚拟化。

镜像加速

Docker 官方和国内很多云服务商都提供了国内加速器服务：

• Docker官方提供的中国镜像库：https://registry.docker-cn.com
• 七牛云加速器：https://reg-mirror.qiniu.com
• 网易加速器：http://hub-mirror.c.163.com

说明：阿里云也提供有镜像，不过没有公开，需要登录阿里云账号获取，https://cr.console.aliyun.com/cn-hangzhou/instances/mirrors。

$ vim /etc/docker/daemon.json
{"registry-mirrors":["https://registry.docker-cn.com"]}
$ sudo systemctl daemon-reload
$ sudo systemctl restart docker

相关命令

# 查看所有命令
$ docker
# 获取镜像
$ docker pull ubuntu
# 创建容器（交互式）
$ docker run -it --name ubuntu ubuntu /bin/bash
  -i: 交互式操作
  -t: 终端
  -d：后台运行（后台式）
# 查看容器
$ docker ps -a
  -a：查看所有容器，包含未启动的容器
  -l：查看最后创建的容器
  -n：最后创建的 n 个容器
# 启动容器
$ docker start id或者name
# 停止容器
$ docker stop id或者name
# 进入容器（在使用 -d 参数时，容器启动后会进入后台。此时想要进入容器，可以通过 attach 或 exec 命令）
# docker exec 命令，因为此退出容器终端，不会导致容器的停止。
$ docker exec -it id或者name /bin/bash
# 导出容器
$ docker export 1e560fca3906 > ubuntu.tar
# 导入容器
$ cat docker/ubuntu.tar | docker import - test/ubuntu:v1
# 删除容器
$ docker rm -f id或name

创建容器有两个命令，一个是docker create，另一个是docker run。二者的区别在于前者创建的容器处于停止状态，而后者不仅创建了容器，而且启动了容器。

更多命令，可以通过命令 docker command --help 更深入的了解。

所有命令

$ docker
Usage:  docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Options:
      --config string      Location of client config files (default "/Users/Jorly/.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 "/Users/Jorly/.docker/ca.pem")
      --tlscert string     Path to TLS certificate file (default "/Users/Jorly/.docker/cert.pem")
      --tlskey string      Path to TLS key file (default "/Users/Jorly/.docker/key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit

Management Commands:
  builder     Manage builds
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  image       Manage images
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  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
  deploy      Deploy a new stack or update an existing stack
  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.