Nationalparks .NET App In this lab, we’re going to deploy a backend service, developed in .NET that will expose 2 main REST endpoints to the visualizer application (parksmap web component that was deployed in the previous labs). The application will query for national parks information (including it’s coordinates) that is stored in a MongoDB database. This application will also provide an external access point, so that the API provided can be directly used by the end user. Background: Source-to-Image (S2I) In a previous lab, we learned how to deploy a pre-existing container image. Now we will expand on that by learning how OpenShift builds container images using source code from an existing repository. This is accomplished using the Source-to-Image project. Source-to-Image (S2I) is a open source project sponsored by Red Hat that has the following goal: Source-to-image (S2I) is a tool for building reproducible container images. S2I produces ready-to-run images by injecting source code into a container image and assembling a new image which incorporates the builder image and built source. The result is then ready to use with docker run. S2I supports incremental builds which re-use previously downloaded dependencies, previously built artifacts, etc. OpenShift is S2I-enabled and can use S2I as one of its build mechanisms (in addition to building container images from Dockerfiles, and "custom" builds). OpenShift runs the S2I process inside a special Pod, called a Build Pod, and thus builds are subject to quotas, limits, resource scheduling, and other aspects of OpenShift. A full discussion of S2I is beyond the scope of this class, but you can find more information about it either in the OpenShift S2I documentation or on GitHub. The only key concept you need to remember about S2I is that it’s magic. Exercise: Creating a .NET application The backend service that we will be deploying as part of this exercise is called nationalparks. This is a .NET application that performs 2D geo-spatial queries against a MongoDB database to locate and return map coordinates of all National Parks in the world. That was just a fancy way of saying that we are going to deploy a webservice that returns a JSON list of places. Add to Project Because the nationalparks component is a backend to serve data that our existing frontend (parksmap) will consume, we are going to build it inside the existing project that we have been working with. To illustrate how you can interact with OpenShift via the CLI or the Web Console, we will deploy the nationalparks component using the web console. Using Application Code on Git Server OpenShift can work with any accessible Git repository. This could be GitHub, GitLab, or any other server that speaks Git. You can even register webhooks in your Git server to initiate OpenShift builds triggered by any update to the application code! NationalParks GitHub Repository Later in the lab, we want you to make a code change and then rebuild your application. This is a fairly simple .NET application. Build the Code on OpenShift Similar to how we used +Add before with an existing image, we can do the same for specifying a source code repository. Since for this lab you have your own git repository, let’s use it with a simple .NET S2I image. In the Developer Perspective, click +Add in the left navigation and then choose From Git. The Import from Git workflow will guide you through the process of deploying your app based on a few selections. Enter the following for Git Repo URL: https://github.com/openshift-roadshow/nationalparks-dotnet.git Select .NET Core as your Builder Image. Scroll down to the General section. Select: Application Name : workshop Name : nationalparks In Resources section, select Deployment. Inside Pipeline section, check Add pipeline box. This will create a Tekton Pipeline for us that we will use after in the Pipeline modules. Click "Show pipeline visualization" to preview the Pipeline inside Pipeline UI that we are going to use later on. Expand the Labels section and add 3 labels: app=workshop (the name we will be giving to the app) component=nationalparks (the name of this deployment) role=backend (the role this component plays in the overall application) Now click the Create button. To see the build logs, in Topology view, click the nationalparks entry, then click on View Logs in the Builds section of the Resources tab. The initial build will take a few minutes to download all of the dependencies needed for the application. You can see all of this happening in real time! From the command line, you can also see the Builds: oc get builds You’ll see output like: NAME TYPE FROM STATUS STARTED DURATION nationalparks-1 Source Git@b052ae6 Running About a minute ago 1m2s You can also view the build logs with the following command: oc logs -f builds/nationalparks-1 After the build has completed and successfully: The S2I process will push the resulting container image to the internal OpenShift registry The Deployment (D) will detect that the image has changed, and this will cause a new deployment to happen. A ReplicaSet (RS) will be spawned for this new deployment. The RS will detect no Pods are running and will cause one to be deployed, as our default replica count is just 1. In the end, when issuing the oc get pods command, you will see that the build Pod has finished (exited) and that an application Pod is in a ready and running state: NAME READY STATUS RESTARTS AGE nationalparks-1-tkid3 1/1 Running 3 2m nationalparks-1-build 0/1 Completed 0 3m parksmap-57df75c46d-xltcs 1/1 Running 0 2h If you look again at the web console, you will notice that, when you create the application this way, OpenShift also creates a Route for you. You can see the URL in the web console, or via the command line: oc get routes Where you should see something like the following: NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD nationalparks nationalparks-workshop.%CLUSTER_SUBDOMAIN% nationalparks 8080-tcp parksmap parksmap-workshop.%CLUSTER_SUBDOMAIN% parksmap 8080-tcp edge none In the above example, the URL is: http://nationalparks-workshop.%CLUSTER_SUBDOMAIN% Since this is a back-end application, it doesn’t actually have a web interface. However, it can still be used with a browser. All backends that work with the parksmap frontend are required to implement a /ws/info/ endpoint. To test, visit this URL in your browser: National Parks Info Page You will see a simple JSON string: {"id":"nationalparks","displayName":"National Parks (C#)","center":{"latitude":47.039304,"longitude":14.505178},"zoom":4} Earlier we said: This is a .NET application that performs 2D geo-spatial queries against a MongoDB database But we don’t have a database. Yet.