一、仓库、镜像、容器的关系

官网图片

docker-architecture.svg

二、Docker镜像

1. 拉取Demo并查看

拉取Hello world镜像

  1. root@ubuntu:/home/jinhua# docker pull hello-world:latest
  2. latest: Pulling from library/hello-world
  3. Digest: sha256:393b81f0ea5a98a7335d7ad44be96fe76ca8eb2eaa76950eb8c989ebf2b78ec0
  4. Status: Image is up to date for hello-world:latest
  5. docker.io/library/hello-world:latest

查看本地的库

  1. root@ubuntu:/home/jinhua# docker images
  2. REPOSITORY    TAG       IMAGE ID       CREATED      SIZE
  3. hello-world   latest    feb5d9fea6a5   2 days ago   13.3kB

运行hello world

  1. root@ubuntu:/home/jinhua# docker run hello-world
  3. Hello from Docker!
  4. This message shows that your installation appears to be working correctly.
  6. To generate this message, Docker took the following steps:
  7.  1. The Docker client contacted the Docker daemon.
  8.  2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
  9.     (amd64)
  10.  3. The Docker daemon created a new container from that image which runs the
  11.     executable that produces the output you are currently reading.
  12.  4. The Docker daemon streamed that output to the Docker client, which sent it
  13.     to your terminal.
  15. To try something more ambitious, you can run an Ubuntu container with:
  16.  $ docker run -it ubuntu bash
  18. Share images, automate workflows, and more with a free Docker ID:
  19.  https://hub.docker.com/
  21. For more examples and ideas, visit:
  22.  https://docs.docker.com/get-started/

命令的含义：

  • docker：应用名
  • run：运行命令
  • hello-world：镜像名

2. 其他运行方式

1. 运行ubuntu镜像的hello-world

  1. root@ubuntu:~# docker run ubuntu:latest /bin/echo "Hello World"
  2. Hello World

同上，其中【/bin/echo “Hello World”】是在容器内部执行的命令

2. 运行交互式的容器

docker 的两个参数 -i -t，让 docker 运行的容器实现”对话”的能力

  • -i：允许对容器内的标准输入（STDIN）进行交互。
  • -t：在容器内指定一个伪终端或终端。
    1. root@ubuntu:~# docker run -it ubuntu:latest
    2. root@974549fe0e32:/# exit
    3. exit
    此时通过exit命令或Ctrl + D命令退出容器。

3. 运行容器至后台

  1. 需要-d命令，使得容器运行至后台。

    1. docker run -d ubuntu:latest /bin/sh -c "while true; do echo hello world; sleep 1; done"
    2. cd804a28ba2725b2832d283fd1b9d5488f96de20398d613dfc2fafe2d6bcae15

    此时输出的并不是预期hello world，而是容器的ID。

  2. 通过docker ps命令查看运行的容器，发现有了ubuntu:latest的容器。

    1. root@ubuntu:~# docker ps
    2. CONTAINER ID   IMAGE           COMMAND                  CREATED         STATUS         PORTS     NAMES
    3. cd804a28ba27   ubuntu:latest   "/bin/sh -c 'while t…"   2 minutes ago   Up 2 minutes             amazing_wu

    输出详情介绍：

  • CONTAINER ID: 容器 ID。
  • IMAGE: 使用的镜像。
  • COMMAND: 启动容器时运行的命令。
  • CREATED: 容器的创建时间。
  • STATUS: 容器状态(状态有7种)。
    • created（已创建）
    • restarting（重启中）
    • running（运行中）
    • removing（迁移中）
    • paused（暂停）
    • exited（停止）
    • dead（死亡）
  • PORTS: 容器的端口信息和使用的连接类型（tcp\udp）。
  • NAMES: 自动分配的容器名称。

  1. 通过docker logs 【容器ID】命令，可以查看到容器真正输出的日志

    1. root@ubuntu:~# docker logs -f cd80
    2. hello world
    3. hello world
    4. hello world
    5. hello world
    6. hello world
    7. hello world
    8. hello world
    9. hello world
    10. hello world
    11. hello world
    12. hello world
    13. hello world

  2. 通过docker stop 【容器ID】命令，停止容器。

    1. root@ubuntu:~# docker stop cd80
    2. cd80

    3. 镜像查找

    1. 本地镜像——docker images

    1. root@ubuntu:~# docker images
    2. REPOSITORY    TAG       IMAGE ID       CREATED       SIZE
    3. hello-world   latest    feb5d9fea6a5   3 days ago    13.3kB
    4. ubuntu        latest    fb52e22af1b0   3 weeks ago   72.8MB

    | 字段 | 含义 | | —- | —- | | Repository | 仓库源 | | tag | 镜像标签 | | Image ID | 镜像ID | | Created | 创建时间 | | Size | 镜像大小 |

2. 镜像搜索——docker search

  1. root@ubuntu:~# docker search mysql
  2. NAME                              DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
  3. mysql                             MySQL is a widely used, open-source relation…   11473     [OK]
  4. mariadb                           MariaDB Server is a high performing open sou…   4356      [OK]
  5. mysql/mysql-server                Optimized MySQL Server Docker images. Create…   848                  [OK]
  6. centos/mysql-57-centos7           MySQL 5.7 SQL database server                   91
  7. mysql/mysql-cluster               Experimental MySQL Cluster Docker images. Cr…   88
  8. centurylink/mysql                 Image containing mysql. Optimized to be link…   59                   [OK]
  9. databack/mysql-backup             Back up mysql databases to... anywhere!         51
  10. prom/mysqld-exporter                                                              42                   [OK]
  11. deitch/mysql-backup               REPLACED! Please use http://hub.docker.com/r…   41                   [OK]
  12. tutum/mysql                       Base docker image to run a MySQL database se…   35
  13. schickling/mysql-backup-s3        Backup MySQL to S3 (supports periodic backup…   31                   [OK]
  14. linuxserver/mysql                 A Mysql container, brought to you by LinuxSe…   31
  15. mysql/mysql-router                MySQL Router provides transparent routing be…   22
  16. centos/mysql-56-centos7           MySQL 5.6 SQL database server                   20
  17. arey/mysql-client                 Run a MySQL client from a docker container      18                   [OK]
  18. fradelg/mysql-cron-backup         MySQL/MariaDB database backup using cron tas…   16                   [OK]
  19. yloeffler/mysql-backup            This image runs mysqldump to backup data usi…   7                    [OK]
  20. genschsa/mysql-employees          MySQL Employee Sample Database                  7                    [OK]
  21. openshift/mysql-55-centos7        DEPRECATED: A Centos7 based MySQL v5.5 image…   6
  22. devilbox/mysql                    Retagged MySQL, MariaDB and PerconaDB offici…   3
  23. jelastic/mysql                    An image of the MySQL database server mainta…   2
  24. ansibleplaybookbundle/mysql-apb   An APB which deploys RHSCL MySQL                2                    [OK]
  25. widdpim/mysql-client              Dockerized MySQL Client (5.7) including Curl…   1                    [OK]
  26. centos/mysql-80-centos7           MySQL 8.0 SQL database server                   1
  27. monasca/mysql-init                A minimal decoupled init container for mysql    0
  • NAME: 镜像仓库源的名称
  • DESCRIPTION: 镜像的描述
  • OFFICIAL: 是否 docker 官方发布
  • STARS: 类似 Github 里面的 star，表示点赞、喜欢的意思。
  • AUTOMATED: 自动构建。

3. 镜像拉取——docker pull

完成后，即可通过 docker images看到拉取到的镜像。

  1. root@ubuntu:~# docker pull centos/mysql-80-centos7
  2. Using default tag: latest
  3. latest: Pulling from centos/mysql-80-centos7
  4. b2cc5146c9c7: Pull complete
  5. 782ee99b4ec9: Pull complete
  6. 28c6947581d3: Pull complete
  7. f622eee2e866: Pull complete
  8. 6aaf4d2a1be7: Downloading [==>                                                ]  3.775MB/75.56MB
  9. 7882d73b48db: Download complete
  10. d3a44e420f48: Download complete
  11. 162c95bdfea5: Download complete
  12. 528c4d56b4cc: Downloading [==============>                                    ]  5.475MB/18.41MB

4. 镜像删除——docker rmi 【镜像ID】

不可以删除【被正在运行容器依赖】的镜像。需要先删除容器docker rm 【容器ID】。

5. 更新镜像