In 2014 Microsoft partnered with Docker and the results are in: Windows Containers combined with Docker give the same great experience we've gotten used to in the Linux world. I've set up a proof of concept to convert the [Docker voting app to Windows Containers](http://blog.alexellis.io/docker-does-sql2016-aspnet/) and have [got msbuild.exe working inside a container](https://twitter.com/alexellisuk/status/782503030038097920) - now let's move on to the next step - continuous integration with [Jenkins CI](https://jenkins.io). We'll look at creating: * a Jenkins master Docker image running on Windows Server Core * a Jenkins agent to run headless in a Windows Container > Now the following is a disclaimer - the CloudBees team can tune Jenkins CI far better than I can. Keep an eye out for an official solution on [Github](https://github.com/jenkinsci/docker) from their team of hackers. ### Create a Java base image The main pre-requisite is a JRE and fortunately [Stefan Scherer](https://github.com/StefanScherer) (a fellow Docker Captain) has come up with a base image. We'll take his Java JRE base image as a template: ``` # escape=` FROM microsoft/windowsservercore RUN powershell -Command ` wget 'http://javadl.oracle.com/webapps/download/AutoDL?BundleId=210185' -Outfile 'C:\jreinstaller.exe' ; ` Start-Process -filepath C:\jreinstaller.exe -passthru -wait -argumentlist "/s,INSTALLDIR=c:\Java\jre1.8.0_91" ; ` del C:\jreinstaller.exe ENV JAVA_HOME c:\\Java\\jre1.8.0_91 RUN setx PATH %PATH%;%JAVA_HOME%\bin CMD [ "java.exe" ] ``` Build this as a local image: ``` $ docker build -t windows-java:jre1.8.0_91 . ``` > Before you share or push this image to the public Docker Hub etc bear in mind that Oracle products such as Java have their own [EULA and licensing terms](http://www.oracle.com/technetwork/java/javase/documentation/index.html). ### Create a Jenkins master image The second pre-requisite for a Jenkins master is to download a Jenkins release as a .war file. Head over to the mirrors site and pick the release you want to work with: [http://mirrors.jenkins-ci.org/war/](http://mirrors.jenkins-ci.org/war/) Now add a layer to download the .war file: ``` FROM windows-java:jre1.8.0_91 ENV HOME /jenkins ENV JENKINS_VERSION 2.0 RUN mkdir \jenkins RUN powershell -Command "wget -Uri https://updates.jenkins-ci.org/download/war/2.0/jenkins.war -UseBasicParsing -OutFile /jenkins/jenkins.war" EXPOSE 8080 EXPOSE 50000 CMD [ "java","-jar", "c:\jenkins\jenkins.war" ] ``` If you have issues with the `CMD` entry please try this instead: ``` CMD java -jar C:\\jenkins\\jenkins.war ``` We have used `wget` an alias in PowerShell for `Invoke-WebRequest`. This may be deprecated in the future but is concise enough for our purposes. * Port 50000 is used for agent/slave communication * Port 8080 provides the web interface Build the image: ``` docker build -t jenkins-windows:2.0 . ``` You can now run your Jenkins master: ``` $ docker run --name jenkinsci -p 8080:8080 -p 50000:50000 -d jenkins-windows:2.0 ``` Since the Jenkins 2.0 release security is enabled by default and you will need to find the *initial password* from the Jenkins container before you can login. ``` $ docker logs jenkinsci ``` **Connecting to Windows Containers** Once you have found the initial password from the logs, you will need to connect to Jenkins in a web-browser. > Due to networking differences between the Linux and Windows Docker implementation you won't be able to access Jenkins through http://localhost:8080. * Type in `docker inspect jenkinsci` * Look for the (NAT) IP address of the container * For Windows 10 - use that IP address in place of localhost. For Windows 2016 use the NAT IP address or the IP address of one of your Ethernet adapters such as http://10.95.11.1:8080. Here's a screenshot of my initial attempt of running the master:

CI is coming to Windows Containers near you thanks @docker @CloudBees @jenkinsci Get Started with this Gist! https://t.co/JHdWBTYMsd pic.twitter.com/jTZcwSa3iO
— Alex Ellis (@alexellisuk) October 3, 2016

### Create a Jenkins agent image A Jenkins agent image can be created and connected headless later on. This is really useful for running through a CLI or script. For this image we'll derive from our Java JRE base image, but this time we don't have to fetch a .jar or .war file from the internet. We can fetch it from our running instance of a Jenkins master. ``` FROM windows-java:jre1.8.0_91 SHELL ["powershell"] ARG BASE_URL ARG SECRET RUN (New-Object System.Net.WebClient).DownloadFile('{0}/jnlpJars/slave.jar' -f $env:BASE_URL, 'slave.jar') ; ENTRYPOINT ["C:\\Java\\jre1.8.0_91\\bin\\java.exe", "-jar", ".\\slave.jar"] ``` For the build pass in the BASE_URL environmental variable like this: ``` $ docker build --build-arg BASE_URL=http://192.168.0.101:8080 -t jenkins_windows_agent:2.0 . ``` Now, add a new agent on the Jenkins UI and look for the "secret" needed to authenticate new agents to the master. ![](/content/images/2016/10/add_node.PNG) Copy the secret and use it when you run your agent: ![](/content/images/2016/10/add_node_2.PNG) ``` $ docker run -ti jenkins_windows_agent -jnlpUrl http://192.168.0.101:8080/computer/Windows/slave-agent.jnlp -secret e9714c100fb003e2cef3609b96a255da5f488bc5f195ef6a0fafcebb2836d4e3 ``` You now have a running agent and can run builds and jobs on it:

Want to run a @jenkinsci master on Linux and build agents on Windows Containers? No problem! @CloudBees @docker https://t.co/Czz45iQDYN pic.twitter.com/3DSiBAHU11
— Alex Ellis (@alexellisuk) October 4, 2016

### Wrapping up You now have a fully-functional Jenkins CI master and agent running on Windows Containers through Docker. Please treat this as a proof of concept and let me know if you have any ideas for improving the level of automation or general experience. The source for the Dockerfiles is available on Github: * [alexellis/windowscontainers-jenkinsci](https://github.com/alexellis/windowscontainers-jenkinsci) Here are a few areas you could move onto with this basis: * Installing custom software such as IIS or .NET into the Jenkins agent * Launching agents through the Docker Swarm plugin (classical) * Enabling the [Blue Ocean UX](http://www.businesswire.com/news/home/20160914005286/en/Jenkins-Community-Builds-Success-Jenkins-2-Powerful) * Integrating containers into the workflow - using a custom Docker registry ### Hire me for Cloud Native / Docker / Go / CI & CD or Kubernetes Could you use some help with a difficult problem, an external view on a new idea or project? Perhaps you would like to build a technology proof of concept before investing more? Get in touch via [sales@openfaas.com](mailto:sales@openfaas.com) or book a session with me on [calendly.com/alexellis](https://calendly.com/alexellis/). ### You may also like * [Gist for MSBuild/ASP.NET in a Container](https://gist.github.com/alexellis/1bceff8a360515f44c566e1a0ba8885f) * [Windows Containers Documentation](https://msdn.microsoft.com/en-gb/virtualization/windowscontainers/containers_welcome) @ MSDN * [Run IIS + ASP.NET on Windows 10 with Docker ](http://blog.alexellis.io/run-iis-asp-net-on-windows-10-with-docker/) * [Docker with Microsoft SQL 2016 + ASP.NET ](http://blog.alexellis.io/docker-does-sql2016-aspnet/)

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