Docker 安裝使用
Ubuntu 16.04
sudo apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
sudo apt-add-repository 'deb https://apt.dockerproject.org/repo ubuntu-xenial main'
sudo apt-get update
apt-cache policy docker-engine
docker-engine:
Installed: (none)
Candidate: 1.11.1-0~xenial
Version table:
1.11.1-0~xenial 500
500 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
1.11.0-0~xenial 500
500 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
sudo apt-get install -y docker-engine
sudo systemctl status docker
- 啟動 docker 程序
sudo service docker start
- Cannot connect to the Docker daemon. Is the docker daemon running on this host?
為了確認docker是否在運行
sudo service docker status
docker start/running, process 2277
這個問題很有可能是權限問題，把執行docker命令的用戶添加到docker，如用戶名為ubuntu，執行
sudo usermod -aG docker ubuntu
- 確定 docker 已經安裝完成
docker run hello-world
Hello from Docker!
This message shows that your installation appears to be working correctly.
To generate this message, Docker took the following steps:
1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
3. The Docker daemon created a new container from that image which runs the
executable that produces the output you are currently reading.
4. The Docker daemon streamed that output to the Docker client, which sent it
to your terminal.
To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash
Share images, automate workflows, and more with a free Docker Hub account:
https://hub.docker.com
For more examples and ideas, visit:
https://docs.docker.com/engine/userguide/
想要知道現在系統上有哪些 Image，可以執行 docker images：
sudo docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
ubuntu 12.04 ebe4be4dd427 4 days ago 210.6 MB
容器環境與 commit
先來指定 ubuntu:12.04 運行一個容器，執行 bash 並在其中裝個 wget 試試：
sudo docker run -t -i ubuntu:12.04 bash
root@37733a045f92:/# apt-get install wget
Reading package lists... Done
... 略
ldconfig deferred processing now taking place
root@37733a045f92:/# exit
執行 docker run 時，-t 在容器中建立了一個終端機，-i 建立與容器標準輸入（STDIN）的互動連結，接下來你就可以在 bash 中進行指令操作了，終端機提示 root@37733a045f92 中，37733a045f92 是目前的容器 ID。
接下來離開 bash 後，重新執行 docker run -t -i ubuntu:12.04 bash，又是原來乾淨的環境了…XD
如果你想要保存在容器中的變更，必須進行 commit，你可以如上進入 bash、安裝 wget，在離開容器之前，在另一個終端機執行 docker ps，查看目前正在運行的容器狀態：
sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
30f63c6e8d15 ubuntu:12.04 bash 12 seconds ago Up 12 seconds stoic_nobel
容器 ID 為 30f63c6e8d15，你可以對照一下容器中 bash 的提示，兩個是對應的，想要 commit 變更，在執行 docker ps 的終端機中執行：
sudo docker commit -m="Added wget" -a="Justin Lin" 30f63c6e8d15 yshihyu/wget
a721d68a588ab4932a5d9881041bec3fac6c5ae6fc26e0f9c459fa08f8ce4f16
sudo docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
yshihyu/wget latest a721d68a588a 8 seconds ago 212 MB
ubuntu 12.04 ebe4be4dd427 4 days ago 210.6 MB
執行 docker commit 成功後，會顯示 commit ID，透過執行 docker images，你可以知道這就是 Image ID，接下來你可以從容器中離開了，執行 sudo docker run -i -t caterpillar/java-tutorial bash，啟用的容器中就已經是安裝有 wget 的環境。
Push 至 Docker hub
在繼續之前，來看看怎麼將你的 Image 放到 Docker hub，你得先在上頭註冊一個帳號，接著回到你的終端機，使用 docker login 登入，然後執行 docker push：
sudo docker login
Username: caterpillar
Password:
Email: caterpillar@openhome.cc
Login Succeeded
~$ sudo docker push caterpillar/java-tutorial
The push refers to a repository [caterpillar/java-tutorial] (len: 1)
Sending image list
Pushing repository caterpillar/java-tutorial (1 tags)
511136ea3c5a: Image already pushed, skipping
4d289a435341: Image already pushed, skipping
994db1cb2425: Image already pushed, skipping
f86a812b1308: Image already pushed, skipping
0b628db0b664: Image already pushed, skipping
ebe4be4dd427: Image already pushed, skipping
a721d68a588a: Image successfully pushed
Pushing tag for rev [a721d68a588a] on {https://registry-1.docker.io/v1/repositories/caterpillar/java-tutorial/tags/latest}
注意！請與先前 Pull 時的訊息比較一下，你會發現 Docker 會比對 Hub 上現有的 Image，不會把你 Local 的 Image 整個上傳，上傳的只有變更的部份，也就是 Image ID 為 a721d68a588a 的 caterpillar/java-tutorial。
使用 Dockerfile 自動建構
要自己一個一個在容器中部署環境，當然是很麻煩的一件事，你可以在 Dockerfile 中撰寫部署步驟，例如：
mkdir java-tutorial
cd java-tutorial
~/java-tutorial$ touch Dockerfile
依照 Java Tutorial 第一堂（2）準備課程環境 的環境需求，我們在 Dockerfile 中撰寫：
FROM caterpillar/java-tutorial
MAINTAINER Justin Lin <caterpillar@openhome.cc>
RUN apt-get -qq update
RUN apt-get -qqy install vim # 男子漢就是要用 vim !!
RUN apt-get -qqy install unzip
RUN apt-get -qqy install git
RUN apt-get -qqy install openjdk-7-jdk
RUN wget http://services.gradle.org/distributions/gradle-1.7-bin.zip
RUN unzip gradle-1.7-bin.zip
RUN rm gradle-1.7-bin.zip
RUN mv gradle-1.7 /usr/lib
RUN ln -s /usr/lib/gradle-1.7/bin/gradle /usr/bin/gradle
RUN git clone https://github.com/codedata/JavaTutorial.git
接著執行 docker build 進行建構：
~/java-tutorial$ sudo docker build -t="caterpillar/java-tutorial" .
Sending build context to Docker daemon 3.584 kB
Sending build context to Docker daemon
Step 0 : FROM caterpillar/java-tutorial
---> a721d68a588a
Step 1 : MAINTAINER Justin Lin <caterpillar@openhome.cc>
---> Using cache
---> 7390f7280de3
Step 2 : RUN apt-get -qq update
---> Running in 93c3f0184d08
---> df3d14686563
Removing intermediate container 93c3f0184d08
Step 3 : RUN apt-get -qqy install vim # 男子漢就是要用 vim !!
---> Running in a7be275d92fd
...略
別忘了最後有個 .，這表示 Dockerfile 來自目前的目錄。建構的過程就可以去做別的事了，建構完成之後，會自動 commit。
Docker 修改默認存儲位置
首先使用 docker info 查看 docker 的基本信息
sudo docker info
Containers: 0
Images: 5
Storage Driver: devicemapper
Pool Name: docker-253:0-679369-pool
Pool Blocksize: 65.54 kB
Backing Filesystem: extfs
Data file:
Metadata file:
Data Space Used: 533.9 MB
Data Space Total: 107.4 GB
Data Space Available: 106.8 GB
Metadata Space Used: 954.4 kB
Metadata Space Total: 2.147 GB
Metadata Space Available: 2.147 GB
Udev Sync Supported: true
Deferred Removal Enabled: false
Library Version: 1.02.89-RHEL6 (2014-09-01)
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 2.6.32-431.29.2.el6.x86_64
Operating System: <unknown>
CPUs: 1
Total Memory: 853.5 MiB
Name: rhel62build
ID: LIO4:I43U:YFQU:SN45:YOE6:7GTF:6AGX:VSKQ:ICIV:AKWD:3OKQ:HUSC
這是一個新裝的docker環境，其中看不出當前docker文件存儲的路徑。但是docker默認會使用 /var/lib/docker 作為默認存儲位置。
停止 Docker 服務
sudo /etc/init.d/docker stop
將原來默認的/var/lib/docker備份一下，然後複製到別的位置並建立一個軟鏈接
cd /var/lib
sudo cp -rf docker docker.bak
sudo mv docker /media/shihyu/ssd/docker
sudo ln -s /media/shihyu/ssd/docker docker
啟動 Docker 服務
sudo /etc/init.d/docker start
最後使用 docker info 查看更新結果
sudo docker info
Containers: 0
Images: 5
Storage Driver: devicemapper
Pool Name: docker-8:21-393695-pool
Pool Blocksize: 65.54 kB
Backing Filesystem: extfs
Data file: /dev/loop1
Metadata file: /dev/loop2
Data Space Used: 533.9 MB
Data Space Total: 107.4 GB
Data Space Available: 15.33 GB
Metadata Space Used: 954.4 kB
Metadata Space Total: 2.147 GB
Metadata Space Available: 2.147 GB
Udev Sync Supported: true
Deferred Removal Enabled: false
Data loop file: /build/docker/devicemapper/devicemapper/data
Metadata loop file: /build/docker/devicemapper/devicemapper/metadata
Library Version: 1.02.89-RHEL6 (2014-09-01)
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 2.6.32-431.29.2.el6.x86_64
Operating System: <unknown>
CPUs: 1
Total Memory: 853.5 MiB
Name: rhel62build
ID: LIO4:I43U:YFQU:SN45:YOE6:7GTF:6AGX:VSKQ:ICIV:AKWD:3OKQ:HUSC
刪除 Docker image
docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
56ee339399dc ubuntu:14.04 "bash" 22 minutes ago Exited (0) 9 minutes ago tender_archimedes
7e889ef55800 yshihyu/ubuntu16 "bash" 22 minutes ago Exited (0) 22 minutes ago elated_brattain
c1e986571728 ubuntu:16.04 "bash" 41 minutes ago Exited (0) 22 minutes ago desperate_kirch
56541fac1049 ubuntu:14.04 "bash" 59 minutes ago Exited (0) 56 minutes ago determined_stonebraker
c8fddb25161f hello-world "/hello" About an hour ago Exited (0) About an hour ago drunk_payne
docker stop c8fddb25161f && docker rm c8fddb25161f