Add a blog post on Azure Container Instances

_posts/2017-07-31-jenkins-azure-container-instances.md

@@ -0,0 +1,125 @@
+---
+layout: post
+title: "Jenkins in seconds with Azure Container Instances"
+tags:
+- azure
+- opensource
+- jenkins
+---
+
+
+Recently Microsoft announced an interesting new addition to their public cloud
+offering: [Azure Container Instances](https://azure.microsoft.com/en-us/blog/announcing-azure-container-instances/).
+Azure Container Instances are fast and billed by the second, which is quite
+compelling on its own. They are interesting in that they provide two novel
+levels of container orchestration, the first is rather basic:"take this
+container and run it." The second is an integration with Kubernetes which
+allows the Kubernetes cluster, most likely one an Azure Container Service, to
+schedule container workloads through Azure Container Instances rather than on
+the existing Kubernetes agents )VMs) via the "ACI connector." As this service
+matures, this could enable some very novel load-based bursting, or cost-saving,
+deployment patterns on top of Kubernetes in Azure.
+
+![Jenkins on Azure Container Instances](/images/post-images/jenkins-aci/jenkins-home.png)_
+
+The Jenkins project has been publishing official releases [as Docker
+containers](https://hub.docker.com/r/jenkins/jenkins) for some time, so last
+Friday I decided it would be interesting to experiment with launching Jenkins
+as an Azure Container Instance. I'll first launch Jenkins "the easy way," then
+review some of the challenges and more advanced approaches.
+
+### The Easy Way
+
+1. Create a Resource Group into which the Azure Container Instance will be deployed:
+   `az group create --name jenkins --location eastus`
+1. Deploy the container:
+   `az container create --image jenkins/jenkins:lts-alpine --name jenkins --resource-group jenkins --ip-address public --port 8080`
+
+In a matter of seconds Jenkins will be up and running. In fact, it seems that
+it takes longer for the JVM to boot than it does for Azure to provision the
+container instance, which is pretty slick.
+
+I can inspect my containers with: `az container list`
+
+    ➜  ~  az container list
+    Name     ResourceGroup    ProvisioningState    Image                       IP:ports             CPU/Memory       OsType    Location
+    -------  ---------------  -------------------  --------------------------  -------------------  ---------------  --------  ----------
+    jenkins  jenkins          Creating             jenkins/jenkins:lts-alpine  52.179.126.248:8080  1.0 core/1.5 gb  Linux     eastus
+    ➜  ~
+
+
+When I navigate to the IP address listed, I'm presented with the familiar
+[Jenkins Post-install Setup
+Wizard](https://jenkins.io/doc/book/getting-started/installing/#setupwizard),
+which prompts me for the administrator token to configure the instance. Again
+using the Azure command line, I can fetch the recent log output with: `az
+container logs --name jenkins --resource-group jenkins`, which dumps something
+like this to my console:
+
+
+    Jul 31, 2017 5:48:33 PM jenkins.install.SetupWizard init
+    INFO:
+
+    *************************************************************
+    *************************************************************
+    *************************************************************
+
+    Jenkins initial setup is required. An admin user has been created and a password generated.
+    Please use the following password to proceed to installation:
+
+    e06025745e4d4c559e9ead0819d0dd1a
+
+    This may also be found at: /var/jenkins_home/secrets/initialAdminPassword
+
+    *************************************************************
+    *************************************************************
+    *************************************************************
+
+    Jul 31, 2017 5:48:34 PM hudson.model.UpdateSite updateData
+    INFO: Obtained the latest update center data file for UpdateSource default
+
+
+With this generated password I can complete the set up of Jenkins and get
+started! **Hurrah!**
+
+### Caveats and Outstanding Questions
+
+Of course, this is really helpful for testing with Jenkins but the example above
+is **stateless**. When I delete the instance (`az container delete --name
+jenkins --resource-group jenkins`) all my configured
+[Pipelines](https://jenkins.io/doc/book/pipeline) and settings are lost. Azure
+Container Instances [do support stateful
+containers](https://docs.microsoft.com/en-us/azure/container-instances/container-instances-mounting-azure-files-volume)
+but it's a bit more tedious to set up than I wanted to cover in this blog post.
+
+
+Another interesting behavior I noticed while working with my Jenkins Azure
+Container Instances was "No valid crumb issued" errors when saving
+configuration. These errors
+typically indicate an aggressive reverse proxy between the end-user and
+Jenkins. This can be easily remedied with the "Enable proxy compatibility"
+setting in the "Configure Global Security" page in Jenkins:
+
+![Crumb compatibility](/images/post-images/jenkins-aci/crumb-proxy.png)
+
+
+Finally, it's not clear how to properly utilize the public IP address assigned
+to the Azure Container Instance. Whether it's something that could be linked
+with Azure DNS, or put behind an Azure Load Balancer.
+
+Azure Container Instances are **very** new to the Azure ecosystem, and as such
+I wouldn't recommend using them for production-level workloads just yet, but
+they do look like a very handy tool for development, testing, and demonstration
+of container-based applications. In the case of Jenkins, if you start
+[automating Jenkins with Groovy](/2017/07/24/groovy-automation-for-jenkins.html) you could readily
+create your own custom Jenkins container which, out of the box, has everything
+configured for testing in seconds via an Azure Container Instance.
+
+
+You can learn more about Azure Container Instances
+[here](https://docs.microsoft.com/en-us/azure/container-instances/), which
+support Linux containers first; Windows support is on the way. The adoption of
+open source tools and technology by Microsoft in Azure is rapidly becoming a
+competitive advantage compared to Amazon Web Services which, as a consumer and
+open source advocate, is very exciting to watch. If you haven't taken a look at
+Azure recently, I recommend it!