Challenge 07 - Updates and Rollbacks

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Introduction

It’s time to update your application, what do you do in a containerized world? Kubernetes makes it easy to safely rollout your new version carefully.

Description

In this challenge you’ll be deploying a v2 of the FabMedical application to your Kubernetes cluster. We’re going to do this using two different update strategies: “Rolling Update” and “Blue/Green Deployment”.

Update the app and load data

• We have staged an updated version of the app on Docker Hub with id and version:
  • whatthehackmsft/content-web:v2
  • whatthehackmsft/content-api:v2
• NOTE: If you have been building your docker container images from source code and deploying to an Azure Container Registry, you can find v2 of the source code in the /Challenge-07 folder of the Resources.zip package.
• Version 2 of FabMedical stores its data in MongoDB. We have provided a container image with an initialization script called “content-init” that loads the database with the sample content. The container runs as a Kubernetes Job. The container image is available on Dockerhub at: whatthehackmsft/content-init.
  • Use the content-init “Job” YAML file provided in the /Challenge-07 folder of the Resources.zip package to run the initialization of MongoDB for our new version of the app.
  • Logs for content-init will provide the detailed logs showing whether it was able to successfully connect and add the contents to the MongoDB. You can use kubectl (or the Azure Portal) to check the logs.
  • You can also verify that the MongoDB contains the FabMedical data after content-init job has completed. Hint: - Connect to the mongodb pod - Use the mongodb command show dbs

Rolling update

• Perform a rolling update of content-web on your cluster to the v2 version of content-web. You will need to edit your deployment to incorporate the following:
  • You’ll be doing this from the command-line with a kubectl command (remember, Kubernetes docs are your friend!)
  • With kubectl and its watch feature you should be able to see new pods with the new version come online and the old pods terminate.
  • At the same time, hit the front page to see when you’re on the new version by refreshing constantly until you see the conference dates updated to 2022.
• Now we are going to roll back this update.
  • Again, this is done from the command-line using a (different) kubectl command.
  • Confirm that we are back to the original version of the app by checking that the conference dates are back to 2017.

    Blue-Green Deployment

• Perform the update again, this time using the blue/green deployment methodology.
  • This time make sure you update BOTH content-web and content-api.
  • You will need a separate deployment file using different tags.
  • Cut over is done by modifying the app’s service to point to this new deployment.
  • The new version of content-api will need to know how to reach the MongoDB server. You will need to pass it an environment variable named: MONGODB_CONNECTION, and this needs to be set the URL: mongodb://mongodb:27017/contentdb

Success Criteria

1. Verify that you are running v2 of the application.
2. Demonstrate that MongoDB has been seeded with speaker and session data.
3. Verify that you have upgraded content-web as a rolling update.
4. Verify that you have rolled back content-web.
5. Verify that you have upgraded both content-web and content-api as a blue/green deployment.