Docker is an open platform for developing, shipping, and running applications. It enables separating applications from infrastructure so software can be delivered quickly. Docker uses features of the Linux kernel like namespaces and cgroups to deliver functionality. Containers are more lightweight than virtual machines, using less disk space and starting faster, while still providing isolation. Docker uses images and repositories to package and distribute applications. The Dockerfile defines how to build images from a base image and run commands.

1. Docker
Jason
2016/9/23

2. Docker
● Docker is written in Go and takes advantage of several features of the Linux
kernel to deliver its functionality.
● Docker is an open platform for developing, shipping, and running
applications
● Docker enables you to separate your applications from your infrastructure so
you can deliver software quickly

3. Comparing Containers And Virtual Machines
Image
Container
Repository

4. Comparing Containers And Virtual Machines
特性 容器 虛擬機器
硬碟使用 一般為 MB 一般為 GB
性能 接近原生 較差
系統支援量 單機支持上千個容器 一般機十個
隔離性 安全隔離 完全隔離
啟動進度 秒級 分鐘級

5. Docker
Image
Container
Repository

6. Docker - Repository
● Public Repository
Docker Hub
Docker Pool
● Private Repository

7. Docker - Repository
14.04 12.04
13.10
5.0 6.0
7.0
Ubuntu Repository CentOS Repository
Repository Server

8. Search image
> docker search mysql

9. Pull image from Repository
> docker pull ubuntu:12.04

10. View image information
> docker images

11. Create container
> docker create ubuntu
Output :79474d40eec0853…...de705a8c5f87673dfa2e6d6e5f

12. Create and run container
> docker run ubuntu:14.04 /bin/echo “Hello world”
Output : Hello world

13. What happens when you run a container
1. Pulls the ubuntu image
2. Creates a new container
3. Allocates a filesystem and mounts a read-write layer:
4. Allocates a network / bridge interface
5. Sets up an IP address
6. Executes a process that you specify
7. Captures and provides application output

14. Create and run container
> docker run -ti ubuntu /bin/bash
> root@af8bae53bdd3:/# pwd

15. List containers
> docker ps -a

16. Building an image from a Dockerfile
● 基礎映像檔資訊
● 維護者資訊
● 映像檔操作指令
● 容器啟動時需執行

17. Dockerfile
● Here is the format of the Dockerfile:
INSTRUCTION arguments
● The instruction is not case-sensitive
● Convention is for them to be UPPERCASE to distinguish them from
arguments more easily.

18. Dockerfile
Dockerfile:
#基礎映像檔資訊
FROM ubuntu:14.04
#維護者資訊
MAINTAINER Jason <Jason@example.com>
#映像檔操作指令
RUN apt-get update && apt-get install -y ruby ruby-dev
RUN gem install sinatra
#容器啟動時需執行
CMD command param1

19. Dockerfile
● ADD <src>... <dest>
● COPY <src>... <dest>
● ENTRYPOINT ["/bin/echo"]
● CMD ["/bin/echo", "this is a echo test"]
● WORKDIR /a
● EXPOSE 5990
● Volume /myVol

20. Build Dockerfile
> docker build -t abc/ub /docker_builder/

21. Create a new image from a container's changes
> docker commit -m "Add file" -a "jason" 0b2616b ubuntu/jason:v2
Output: sha256:7030a919c…..109a5c3074d3971ddaa4ca2ce20f

22. Delete container and image
● Delete a container
> docker rm [Container ID]
● Delete a image
> docker rmi [Container ID]

23. Other command
docker inspect [container ID]
docker logs [container ID]
docker start [container ID]
docker stop [container ID]
docker attach [container ID]
docker run -d ubuntu:14.04
docker run -P ubuntu:14.04
docker run -p 27019:27017 mongo

24. Reference
Docker
https://docs.docker.com/
https://philipzheng.gitbooks.io/docker_practice/content/image/create.html