Docker理论与实践（二）

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Docker学习笔记_For_Mac

文章作者：Tyan
博客：noahsnail.com

1. Docker命令

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# 列出系统中的所有容器
docker ps -a

# 结果
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                      PORTS               NAMES
aadf299b179b        hello-world         "/hello"            20 minutes ago      Exited (0) 20 minutes ago                       gloomy_khorana

# docker ps仅列出当前运行的容器
docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

# 运行whalesay镜像
docker fun docker/whalesay cowsay boo

1.1 docker run hello-world解析

这个命令总共有三部分：

  • docker：告诉操作系统你使用的是docker程序

  • run：创建和运行docker容器的子命令

  • hello-world：告诉docker将哪一个镜像加载到容器中

1.2 docker run hello-world的运行过程

image是一个文件系统，里面有运行时使用的参数。它没有状态且不能改变。容器是镜像的运行实例。命令执行时，Docker Engine会进行以下的步骤：

  1. 检查hello-world软件镜像是否存在

  2. 如果不存在，从Docker Hub上下载hello-world

  3. 加载镜像到容器中并运行

运行是根据镜像的构建过程执行的，可能一直运行，也可能执行几个命令就退出。镜像可能是非常复杂的，例如镜像可以启动一个数据库软件。

2. 创建自己的docker image

2.1 写一个Dockerfile

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$ mkdir Docker

$ cd Docker

$ touch Dockerfile

$ vim Dockerfile

在Dockerfile中加入下面的代码并保存：

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FROM docker/whalesay:latest
RUN apt-get -y update && apt-get install -y fortunes
CMD /usr/games/fortune -a | cowsay

2.2 从Dockerfile中创建image

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# 查看Dockerfile内容
$ cat Dockerfile

# 构建image
$ docker build -t docker-whale .

2.3 创建image的过程

  • 首先Docker检查确保有构建的需要的东西
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Sending build context to Docker daemon 2.048 kB
  • 然后Docker加载whalesay镜像
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Step 1 : FROM docker/whalesay:latest
 ---> 6b362a9f73eb
  • Docker开始执行apt-get命令
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Step 2 : RUN apt-get -y update && apt-get install -y fortunes
 ---> Running in 3c381fdef64a
Ign http://archive.ubuntu.com trusty InRelease
Get:1 http://archive.ubuntu.com trusty-updates InRelease [65.9 kB]
Get:2 http://archive.ubuntu.com trusty-security InRelease [65.9 kB]
Hit http://archive.ubuntu.com trusty Release.gpg
Get:3 http://archive.ubuntu.com trusty-updates/main Sources [473 kB]
Get:4 http://archive.ubuntu.com trusty-updates/restricted Sources [5247 B]
Get:5 http://archive.ubuntu.com trusty-updates/universe Sources [207 kB]
Get:6 http://archive.ubuntu.com trusty-updates/main amd64 Packages [1122 kB]
Get:7 http://archive.ubuntu.com trusty-updates/restricted amd64 Packages [23.5 kB]
Get:8 http://archive.ubuntu.com trusty-updates/universe amd64 Packages [483 kB]
Hit http://archive.ubuntu.com trusty Release
Get:9 http://archive.ubuntu.com trusty-security/main Sources [152 kB]
Get:10 http://archive.ubuntu.com trusty-security/restricted Sources [3944 B]
Get:11 http://archive.ubuntu.com trusty-security/universe Sources [49.4 kB]
Get:12 http://archive.ubuntu.com trusty-security/main amd64 Packages [659 kB]
Get:13 http://archive.ubuntu.com trusty-security/restricted amd64 Packages [20.2 kB]
Get:14 http://archive.ubuntu.com trusty-security/universe amd64 Packages [178 kB]
Hit http://archive.ubuntu.com trusty/main Sources
Hit http://archive.ubuntu.com trusty/restricted Sources
Hit http://archive.ubuntu.com trusty/universe Sources
Hit http://archive.ubuntu.com trusty/main amd64 Packages
Hit http://archive.ubuntu.com trusty/restricted amd64 Packages
Hit http://archive.ubuntu.com trusty/universe amd64 Packages
Fetched 3508 kB in 25s (139 kB/s)
Reading package lists...
Reading package lists...
Building dependency tree...
Reading state information...
The following extra packages will be installed:
  fortune-mod fortunes-min librecode0
Suggested packages:
  x11-utils bsdmainutils
The following NEW packages will be installed:
  fortune-mod fortunes fortunes-min librecode0
0 upgraded, 4 newly installed, 0 to remove and 87 not upgraded.
Need to get 1961 kB of archives.
After this operation, 4817 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu/ trusty/main librecode0 amd64 3.6-21 [771 kB]
Get:2 http://archive.ubuntu.com/ubuntu/ trusty/universe fortune-mod amd64 1:1.99.1-7 [39.5 kB]
Get:3 http://archive.ubuntu.com/ubuntu/ trusty/universe fortunes-min all 1:1.99.1-7 [61.8 kB]
Get:4 http://archive.ubuntu.com/ubuntu/ trusty/universe fortunes all 1:1.99.1-7 [1089 kB]
debconf: unable to initialize frontend: Dialog
debconf: (TERM is not set, so the dialog frontend is not usable.)
debconf: falling back to frontend: Readline
debconf: unable to initialize frontend: Readline
debconf: (This frontend requires a controlling tty.)
debconf: falling back to frontend: Teletype
dpkg-preconfigure: unable to re-open stdin: 
Fetched 1961 kB in 8s (221 kB/s)
Selecting previously unselected package librecode0:amd64.
(Reading database ... 13116 files and directories currently installed.)
Preparing to unpack .../librecode0_3.6-21_amd64.deb ...
Unpacking librecode0:amd64 (3.6-21) ...
Selecting previously unselected package fortune-mod.
Preparing to unpack .../fortune-mod_1%3a1.99.1-7_amd64.deb ...
Unpacking fortune-mod (1:1.99.1-7) ...
Selecting previously unselected package fortunes-min.
Preparing to unpack .../fortunes-min_1%3a1.99.1-7_all.deb ...
Unpacking fortunes-min (1:1.99.1-7) ...
Selecting previously unselected package fortunes.
Preparing to unpack .../fortunes_1%3a1.99.1-7_all.deb ...
Unpacking fortunes (1:1.99.1-7) ...
Setting up librecode0:amd64 (3.6-21) ...
Setting up fortune-mod (1:1.99.1-7) ...
Setting up fortunes-min (1:1.99.1-7) ...
Setting up fortunes (1:1.99.1-7) ...
Processing triggers for libc-bin (2.19-0ubuntu6.6) ...
 ---> 5c6dbfc7a7ea
  • 执行CMD命令
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Removing intermediate container 3c381fdef64a
Step 3 : CMD /usr/games/fortune -a | cowsay
 ---> Running in b0df80e0d4c9
 ---> d1178b780ac6
Removing intermediate container b0df80e0d4c9
Successfully built d1178b780ac6

2.4 测试自己创建的image

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$ docker images

$ docker run docker-whale

# 结果
 _________________________________________ 
/ I suppose some of the variation between \
| Boston drivers and the rest of the      |
| country is due to the progressive       |
| Massachusetts Driver Education Manual   |
| which I happen to have in my top desk   |
| drawer. Some of the Tips for Better     |
| Driving are worth considering, to wit:  |
|                                         |
| [131.16d]:                              |
|                                         |
| "Directional signals are generally not  |
| used except during vehicle              |
|                                         |
| inspection; however, a left-turn signal |
| is appropriate when making              |
|                                         |
| a U-turn on a divided highway."         |
|                                         |
| [96.7b]:                                |
|                                         |
| "When paying tolls, remember that it is |
| necessary to release the                |
|                                         |
| quarter a full 3 seconds before passing |
| the basket if you are                   |
|                                         |
| traveling more than 60 MPH."            |
|                                         |
| [110.13]:                               |
|                                         |
| "When traveling on a one-way street,    |
| stay to the right, so as not            |
|                                         |
\ to interfere with oncoming traffic."    /
 ----------------------------------------- 
    \
     \
      \     
                    ##        .            
              ## ## ##       ==            
           ## ## ## ##      ===            
       /""""""""""""""""___/ ===        
  ~~~ {~~ ~~~~ ~~~ ~~~~ ~~ ~ /  ===- ~~~   
       \______ o          __/            
        \    \        __/             
          \____\______/

3. 在Docker Hub上创建自己的仓库，与Git类似

略.

4. Tag, push, and pull your image

Step 1: Tag and push the image

  • 用docker images查看你当前的image
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REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
docker-whale        latest              d1178b780ac6        2 hours ago         274.9 MB
hello-world         latest              c54a2cc56cbb        11 weeks ago        1.848 kB
docker/whalesay     latest              6b362a9f73eb        16 months ago       247 MB
  • 用docker tag命令和IMAGE ID给image打上tag，YOUR_DOCKERHUB_NAME为你的Docker Hub帐号，它起一个namespace的作用
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docker tag d1178b780ac6 YOUR_DOCKERHUB_NAME/docker-whale:latest
  • docker images重新查看image
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REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
docker-whale             latest              d1178b780ac6        2 hours ago         274.9 MB
snailtyan/docker-whale   latest              d1178b780ac6        2 hours ago         274.9 MB
hello-world              latest              c54a2cc56cbb        11 weeks ago        1.848 kB
docker/whalesay          latest              6b362a9f73eb        16 months ago       247 MB
  • 使用docker login命令登录你的Docker Hub账户
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$ docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: ***
Password: 
Login Succeeded
  • 使用docker push将image推送到Docker Hub
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$ docker push ***/docker-whale
The push refers to a repository [docker.io/***/docker-whale]
122284833f25: Pushed 
5f70bf18a086: Mounted from docker/whalesay 
d061ee1340ec: Mounted from docker/whalesay 
d511ed9e12e1: Mounted from docker/whalesay 
091abc5148e4: Mounted from docker/whalesay 
b26122d57afa: Mounted from docker/whalesay 
37ee47034d9b: Mounted from docker/whalesay 
528c8710fd95: Mounted from docker/whalesay 
1154ba695078: Mounted from docker/whalesay 
latest: digest: sha256:18a6032f5726bdd6cea7c15faa02d9dcf1f12ff591c42ca15fc95c0d83de04fc size: 2614
  • 你可以在你的Docker Hub上看到*/docker-whale image了

Step 2: Pull your new image

  • 先删除本地的docker-whale
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# 用id删除image
$ docker rmi -f 7d9495d03763

# 用name删除image
$ docker rmi -f docker-whale
  • 通过docker run来pull image
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$ docker run ***/docker-whale
Unable to find image '***/docker-whale:latest' locally
latest: Pulling from ***/docker-whale

e190868d63f8: Already exists 
909cd34c6fd7: Already exists 
0b9bfabab7c1: Already exists 
a3ed95caeb02: Already exists 
00bf65475aba: Already exists 
c57b6bcc83e3: Already exists 
8978f6879e2f: Already exists 
8eed3712d2cf: Already exists 
2bb8a73a1829: Already exists 
Digest: sha256:18a6032f5726bdd6cea7c15faa02d9dcf1f12ff591c42ca15fc95c0d83de04fc
Status: Downloaded newer image for ***/docker-whale:latest
 ________________________________________ 
/ Would it help if I got out and pushed? \
|                                        |
\ -- Princess Leia Organa                /
 ---------------------------------------- 
    \
     \
      \     
                    ##        .            
              ## ## ##       ==            
           ## ## ## ##      ===            
       /""""""""""""""""___/ ===        
  ~~~ {~~ ~~~~ ~~~ ~~~~ ~~ ~ /  ===- ~~~   
       \______ o          __/            
        \    \        __/             
          \____\______/
如果有收获，可以请我喝杯咖啡！