Docker Martin Meyer

Agenda What is Docker? –Docker vs. Virtual Machine –History, Status, Run Platforms Hello World Terminology: Image and Containers Volume Mounting, Port Publishing, Linking Dockerfile, Dockerhub Resource Usage 2

3 What is Docker? Docker is an open-source project that automates the deployment of applications inside software containers, by providing an additional layer of abstraction and automation of operating system–level virtualization on Linux. [Source: en.wikipedia.org]

4 Docker: Name docker [naut.]: der Dockarbeiter, der Hafenarbeiter Source: leo.org Provide a uniformed wrapper around a software package: «Build, Ship and Run Any App, Anywhere» [ –Similar to shipping containers: The container is always the same, regardless of the contents and thus fits to all trucks, cranes, ships,... [

5 Docker vs. Virtual Machine Source:

6 Docker Technology libvirt: Platform Virtualization LXC (LinuX Containers): Multiple isolated Linux systems (containers) on a single host Layered File System [Source:

7 Docker History : Releases as Open Source : Red Hat collaboration (Fedora, RHEL, OpenShift) : 34th most starred GitHub project : JAX Innovation Award (most innovative open technology)

8 Technology Radar : Assess : Trial Source: /tools/docker

9 Run Platforms Various Linux distributions (Ubuntu, Fedora, RHEL, Centos, openSUSE,...) Cloud (Amazon EC2, Google Compute Engine, Rackspace) : Microsoft announces plans to integrate Docker with next release of Windows Server

10 Hello World Simple Command - Ad-Hoc Container Windows: VirtualBox VM (boot2docker) –Use boot2docker link to connect to VM in command prompt (better graphics) docker run ubuntu /bin/echo ‘Hello World’ – docker images [-a] – docker ps –a

11 Terminology - Image Persisted snapshot that can be run –images: List all local images –run: Create a container from an image and execute a command in it –tag: Tag an image –pull: Download image from repository –rmi: Delete a local image This will also remove intermediate images if no longer used

12 Terminology - Container Runnable instance of an image –ps: List all running containers –ps –a: List all containers (incl. stopped) –top: Display processes of a container –start: Start a stopped container –stop: Stop a running container –pause: Pause all processes within a container –rm: Delete a container –commit: Create an image from a container

13 Daemon Container Open Terminal in container: – docker run –it ubuntu /bin/bash Make any modification We can create a new image with the modifications: –Docker commit [containerId] [image] Image: e.g. mytest/test1:1.0 Run as deamon: docker run –d [image] command – docker logs [-f] [containerId]

14 Mount Volumes Log to host file Adapt script to log to /log/hello3.log docker run -d –v /home/docker/log:/log /bin/bash /sayHello.sh Run second container: Volume can be shared

15 Publish Port Sample Web-Server: training/webapp – ng/webapp/ ng/webapp/ docker run –d –P trianing/webapp –Random host port docker run –d –p 20000:5000 trianing/webapp –Map container port 5000 to host port 20000

16 Link Containers Data Volumes can be shared between containers Network information of dependent container can be injected: – docker run --name my_serv1 –d –e PROVIDER=Serv1 training/webapp – docker run –ti --link my_serv1:serv1 ubuntu /bin/bash set wget -qO- $SERV1_PORT_5000_TCP_ADDR:$SERV1_PORT_5000_ TCP_PORT

17 Dockerfile Create images automatically using a build script: «Dockerfile» Can be versioned in a version control system like Git or SVN, along with all dependencies Docker Hub can automatically build images based on dockerfiles on Github

18 Dockerfile Example Dockerfile: – FROM training/webapp ADD testFile.txt /testFile.txt ENV PROVIDER MyDockerFile Add testFile.txt docker build [DockerFileDir] docker inspect [imageId]

19 Docker Hub Public repository of Docker images – –docker search [term] Automated: Has been automatically built from Dockerfile –Source for build is available on GitHub

20 Resource Usage top / ps / free -m Start 100 WebServer containers –docker run -d -p $hostPort:5000 -e "PROVIDER=$provider" training/webapp docker ps [containerId] top / ps / free -m

21 Documentation Docker homepage: –Introduction: –Online tutorial: –Installation and user guide: InfTec TecBoard: ocker ocker –Includes this presentation

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