Run .Net 7 code on Red Hat OpenShift Container Platform on MacOS

In this tutorial we will create a simple Hello World .Net 7 application and run it on a desktop instance of Red Hat OpenShift designed for testing applications locally called OpenShift Local.

The tutorial will demonstrate how easy it is to get started with development in Kubernetes with the Red Hat OpenShift Container Platform (OCP). OCP supports many languages and you can easily bring your .Net code to the world of containers and Kubernetes with OCP.

Pre-req .Net 7 SDK

• Note: I'm using a Mac for this example.
• Download and install .Net 7 SDK for your OS. For this tutorial I used Microsoft's installation package for SDK 7.0.102.

Install the .Net SDK per the instructions for your OS and test your .Net SDK installation.

% dotnet --version
7.0.102

Install Red Hat OpenShift Local

For this next step you will need a Red Hat account.

Download the Red Hat OpenShift Local (RHOL) for you OS from the Red Hat Hybrid Cloud Console Create an OpenShift cluster

Choose the "local" tab and select your OS.

After you download RHOL, click the Download pull secret button.

After you download the code run the installer.

Prepare your Red Hat OpenShift Local environment

After installing RHOL, we will do the rest of the work on the command line. On the Mac open a Terminal window. I placed the pull secret in my home Documents folder in a folder I labeled rhol. On the Mac or Linux it might look like this: ~/Documents/rhol

% mv pull-secret ~/Documents/rhol/

Check the RHOL version. Note that RHOL still uses the previous Code Ready Containers acronym - crc - on the command line to start and manage RHOL. As of 01/24/2023 the latest release RHOL is 2.13.1 with OpenShift 4.12.

% crc version
CRC version: 2.13.1+b5b864fd
OpenShift version: 4.12.0
Podman version: 4.3.1

Run the setup command to download the RHOL bundle and prep your environment. The RHOL setup typically takes a few minutesd.

% crc setup
RHOL is constantly improving and we would like to know more about usage (more details at https://developers.redhat.com/article/tool-data-collection)
...
Your system is correctly setup for using CRC. Use 'crc start' to start the instance

Start up Red Hat OpenShift Local

Start up RHOL and include the pull secret you previously downloaded.

% crc start -p ~/Documents/rhol/pull-secret
INFO Checking if running as non-root              
INFO Checking if crc-admin-helper executable is cached 
...

Depending on your hardware, it may take several minutes for RHOL to startup. Be sure to copy the login information that is displayed in the terminal after starting RHOL. See example output below.

...
INFO Adding crc-admin and crc-developer contexts to kubeconfig... 
Started the OpenShift cluster.

The server is accessible via web console at:
  https://console-openshift-console.apps-crc.testing

Log in as administrator:
  Username: kubeadmin
  Password: zXje7-...-6aUho

Log in as user:
  Username: developer
  Password: developer

Use the 'oc' command line interface:
  $ eval $(crc oc-env)
  $ oc login -u developer https://api.crc.testing:6443

We can check the status of RHOL with crc status command:

% crc status
CRC VM:          Running
OpenShift:       Running (v4.12.0)
RAM Usage:       6.352GB of 9.399GB
Disk Usage:      15.29GB of 32.74GB (Inside the CRC VM)
Cache Usage:     73.7GB
Cache Directory: /Users/palucas/.crc/cache

We can test our login to RHOL with the information from the installation. We use the oc login command and provide the username and password along with the URL to the RHOL Server.

% eval $(crc oc-env)
% oc login -u developer -p developer https://api.crc.testing:6443
Login successful.

You have access to 67 projects, the list has been suppressed. You can list all projects with 'oc projects'

Using project "default".

Create a sample Hello World .Net web app

Let's create our sample .Net application. Choose a directory where you would like to store your sample application. I created my sample Hello World .Net web app in a directory called projects. We will use the .Net Model-View-Controller (mvc) template to build our sample .Net application.

% dotnet new mvc -o myWebApp --no-https

When the sample app code has finished generating change into the applications's directory and start up the application to test it.

% cd myWebApp
% dotnet run
Building...
...
info: Microsoft.Hosting.Lifetime[0]
      Content root path: /Users/palucas/projects/myWebApp

The app starts up quickly and is ready to test when Content root path:... printed to the terminal screen. Follow the instructions to access the application via a browser.

The URL for my sample app was found on this line in the terminal output.

Now listening on: http://localhost:5206

When you are finished return to the terminal window and type Ctrl-c to stop the .Net test server.

Prepare our .Net application for OpenShift Container Platform (RHOL)

Throughout the tutorial I'll refer to Red Hat OpenShift Local as OpenShift Container platform (OCP). Use the following command to make the .Net app ready for the OCP build and deploy process. The dotnet publish command preps the application for deployment storing the .Net artifacts in a release folder. The -f switch sets the framework to the .Net 7.0 framework and -c switch defines it as a build configuration.

% cd ..
% dotnet publish myWebApp -f net7.0 -c Release
MSBuild version 17.4.1+9a89d02ff for .NET
  Determining projects to restore...
  All projects are up-to-date for restore.
  myWebApp -> /Users/palucas/projects/myWebApp/bin/Release/net7.0/myWebApp.dll
  myWebApp -> /Users/palucas/projects/myWebApp/bin/Release/net7.0/publish/

Prep OCP for .Net

Login to OCP with the username developer.

% eval $(crc oc-env)
% oc login -u developer -p developer https://api.crc.testing:6443
Login successful.

You don't have any projects. You can try to create a new project, by running

    oc new-project <projectname>

To see who you are logged in as type the following:

% oc whoami
developer

Create a new OCP project (K8s namespace) for our .Net Welcome application.

% oc new-project my-first-app
Now using project "my-first-app" on server "https://api.crc.testing:6443".

You can add applications to this project with the 'new-app' command. For example, try:

    oc new-app rails-postgresql-example

to build a new example application in Ruby. Or use kubectl to deploy a simple Kubernetes application:

    kubectl create deployment hello-node --image=k8s.gcr.io/e2e-test-images/agnhost:2.33 -- /agnhost serve-hostname

You can check the project you are currently in with the following oc command:

% oc get projects
NAME           DISPLAY NAME   STATUS
my-first-app                  Active

Image streams makes it easy to build and deploy our .Net app in a container and can be used to trigger new deployments when a new image becomes available If this is your first .Net project in RHOL, then you'll need to add a .Net image stream to our OCP environment. See links the appendix section for more information on image streams.

% oc create -f https://raw.githubusercontent.com/redhat-developer/s2i-dotnetcore/master/dotnet_imagestreams.json
imagestream.image.openshift.io/dotnet created
imagestream.image.openshift.io/dotnet-runtime created

Build, Deploy and access your new .Net app

Create a new build configuration. We will use a Red Hat Universal Base Image (ubi8) that includes the .Net 7 SDK and runtimes on Red Hat Enterprise Linux 8. UBI containers are OCI-compliant. We are building the app from binary contents.

% oc new-build --name=my-web-app dotnet:7.0-ubi8 --binary=true
warning: Cannot check if git requires authentication.
--> Found image 3aceb77 (8 days old) in image stream "my-first-app/dotnet" under tag "7.0-ubi8" for "dotnet:7.0-ubi8"

    .NET 7 
    ------ 
    Platform for building and running .NET 7 applications

    Tags: builder, .net, dotnet, dotnetcore, dotnet-70

    * A source build using binary input will be created
      * The resulting image will be pushed to image stream tag "my-web-app:latest"
      * A binary build was created, use 'oc start-build --from-dir' to trigger a new build

--> Creating resources with label build=my-web-app ...
    imagestream.image.openshift.io "my-web-app" created
    buildconfig.build.openshift.io "my-web-app" created
--> Success

Start the build and specify the path to the binary artifacts in .Net project (I'm at the "root" of my project folder myWebApp).

oc start-build my-web-app --from-dir=bin/Release/net7.0/publish
Uploading directory "bin/Release/net7.0/publish" as binary input for the build ...
....
Uploading finished
build.build.openshift.io/my-web-app-1 started

You can also check the status of the build process in the log file to see when the build is completed.

% oc logs -f bc/my-web-app
Receiving source from STDIN as archive ...
...
Push successful

Create our new application on OCP.

% oc new-app my-web-app
--> Found image fb95e95 (About a minute old) in image stream "my-first-app/my-web-app" under tag "latest" for "my-web-app"

    .NET 7 
    ------ 
    Platform for building and running .NET 7 applications

    Tags: builder, .net, dotnet, dotnetcore, dotnet-70


--> Creating resources ...
Warning: would violate PodSecurity "restricted:v1.24": allowPrivilegeEscalation != false (container "my-web-app" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container "my-web-app" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "my-web-app" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "my-web-app" must set securityContext.seccompProfile.type to "RuntimeDefault" or "Localhost")
    deployment.apps "my-web-app" created
    service "my-web-app" created
--> Success
    Application is not exposed. You can expose services to the outside world by executing one or more of the commands below:
     'oc expose service/my-web-app' 
    Run 'oc status' to view your app.

You can check the status of your app deployment.

% oc status
In project my-first-app on server https://api.crc.testing:6443

svc/my-web-app - 10.217.5.240:8080
  deployment/my-web-app deploys istag/my-web-app:latest <-
    bc/my-web-app source builds uploaded code on istag/dotnet:7.0-ubi8 
    deployment #2 running for 49 seconds - 1 pod
    deployment #1 deployed 51 seconds ago


1 info identified, use 'oc status --suggest' to see details.

We can see that the ClusterIP service is created with application build and deployment.

% oc get svc
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
my-web-app   ClusterIP   10.217.5.240   <none>        8080/TCP   105s

Let's expose the app to the world by creating a route to the app.

% oc expose svc/my-web-app
route.route.openshift.io/my-web-app exposed

Let's see the route we just created.

% oc get route/my-web-app
NAME         HOST/PORT                                  PATH   SERVICES     PORT       TERMINATION   WILDCARD
my-web-app   my-web-app-my-first-app.apps-crc.testing          my-web-app   8080-tcp                 None

Let's get the url for the application. We can use the oc status command to get the URL to the application after exposing the application's service to the outside world.

% oc status
In project my-first-app on server https://api.crc.testing:6443

http://my-web-app-my-first-app.apps-crc.testing to pod port 8080-tcp (svc/my-web-app)
  deployment/my-web-app deploys istag/my-web-app:latest <-
    bc/my-web-app source builds uploaded code on istag/dotnet:7.0-ubi8 
    deployment #2 running for 17 hours - 1 pod
    deployment #1 deployed 17 hours ago


1 info identified, use 'oc status --suggest' to see details.

Go to your web browser and type in the url http://my-web-app-my-first-app.apps-crc.testing to see your app running in OCP. 

Back at the command we can examine some components running on OCP. We've previously seen services and routes related to our application. Let's look at what pods are in our project.

% oc get pods
NAME                         READY   STATUS      RESTARTS   AGE
my-web-app-1-build           0/1     Completed   0          10m
my-web-app-ddfbd687b-9h5tf   1/1     Running     0          7m43s

And we can see our deployments in our project.

% oc get deployments
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
my-web-app   1/1     1            1           8m4s

Access the OCP console to see your project and application

Let's take a brief look at the OCP Administration Console.

% crc console
Opening the OpenShift Web Console in the default browser...

The crc console command launches the ODP console in your default browser. Typically the URL looks like https://console-openshift-console.apps-crc.testing/ Your browser will tell you that your connection is not private as the OCP TLS certificate is not installed with your broswer certificates. Accept any certificates presented to you.

Enter your Username and Password, and click the blue Login button.

When logging into the OCP console for the first time, you may offered to take a tour of the console. Feel free to take the tour or skip it.

Currently we are logged in as the developer username with the Developer view of the OCP Console. Click on the Topology tab on the side menu bar to see the topology of our application. We can see our application has successfully deployed with the green check circle. On the upper right we click the arrow to open application UI in a new browser tab. If we click the app name a side screen will open with additional application deployment details

We can view Details, Resources and Observe (monitor) our application. Clicking on the Resources tab shows us the Kubernetes objects associated with our project.

While logged in as the developer we can change the console view from the Developer view to the Administrator view. We can create, review and observe all the Kubernetes objects that make up our application(s) running in OpenShift.

Updating the Application

Let's make a simple change to our application and then update it on OCP.

Let's change the "Welcome" message to "Welcome to .Net running on Red Hat OpenShift Container Platform!".

Back at the folder containing your .Net project, navigate to the Home directory under your project.

% cd ~/projects/myWebApp/Views/Home

In the Home directory open the file titled Index.cshtml with your favorite editor.

% vi Index.cshtml

Change the following line:

<h1 class="display-4">Welcome</h1>

to:

<h1 class="display-4">Welcome to .Net running on Red Hat OpenShift Containe Platformr</h1>

My file looks like the following code.

@{
    ViewData["Title"] = "Home Page";
}

<div class="text-center">
    <h1 class="display-4">Welcome to .Net running on Red Hat OpenShift Container Platform</h1>
    <p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
</div>

Let's test our change locally in .Net. Go back to the "root" of your project folder and rerun the application to see the changed message.

% cd ~/projects/myWebApp 
% dotnet run

From the projects directory rebuild the changed .Net artifacts.

% dotnet publish myWebApp -f net7.0 -c Release
MSBuild version 17.4.1+9a89d02ff for .NET
  Determining projects to restore...
  All projects are up-to-date for restore.
  myWebApp -> /Users/palucas/projects/myWebApp/bin/Release/net7.0/myWebApp.dll
  myWebApp -> /Users/palucas/projects/myWebApp/bin/Release/net7.0/publish/

Let's deploy the application update to OCP.

Login to OCP as developer. Make sure you see that you are using the same project we originally created for our first application.

% eval $(crc oc-env)
% % oc login -u developer -p developer https://api.crc.testing:6443
Login successful.

You have one project on this server: "my-first-app"

Using project "my-first-app".

You can also check your current project with the following command:

% oc get project
NAME           DISPLAY NAME   STATUS
my-first-app                  Active

Rebuild and deploy the updated application. Since we have an existing project with the associated kubernetes objects, deploying our application update is very easy with OCP.

% oc start-build my-web-app --from-dir=bin/Release/net7.0/publish
Uploading directory "bin/Release/net7.0/publish" as binary input for the build ...
.
Uploading finished
build.build.openshift.io/my-web-app-2 started

Let's check the status of the build process of our updated application.

% oc status
In project my-first-app on server https://api.crc.testing:6443

http://my-web-app-my-first-app.apps-crc.testing to pod port 8080-tcp (svc/my-web-app)
  deployment/my-web-app deploys istag/my-web-app:latest <-
    bc/my-web-app source builds uploaded code on istag/dotnet:7.0-ubi8 
      build #2 running for 17 seconds
      build #1 succeeded 19 hours ago
    deployment #2 running for 19 hours - 1 pod
    deployment #1 deployed 19 hours ago


1 info identified, use 'oc status --suggest' to see details.

Let's check the log file of the build configuration to see when the build finishes. Watch for the 'Push successful' message which indicates the update is finished.

% oc logs -f bc/my-web-app 
Receiving source from STDIN as archive ...
...
Push successful

If you forgot the URL to our sample application, use the oc status command to get the application URL.

% oc status
In project my-first-app on server https://api.crc.testing:6443

http://my-web-app-my-first-app.apps-crc.testing to pod port 8080-tcp (svc/my-web-app)
...

You'll now see the new version of our application has been deployed to OCP. 

Go back to the OCP console and change to the Administrator view. We can see the new build config under the Workloads section, and the new Pod instance for our application. 

Conclusion

From this brief tutorial we can see how easy it is to bring our .Net applications in to a modern enterprise ready kubernetes platform like OpenShift. OpenShift can run anywhere from the desktop to the datacenter to the public cloud in any hybrid combination. OCP is flexible enough to integrate OCP into your .Net CI/CD pipeline using tools like Visual Code and GitLab to make for a fast and efficient enterprise software lifecycle environment.

References

• Getting Start Guided - 2.13
• Product Documentation for .NET 7.0
• Managing Imagestreams OCP 4.12