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Canary deployment

In this lab we are going to create a canary deployment. The idea behind canary deployment (or rollout) is to introduce a new version of an application by first testing it using a small percentage of user traffic, and then if all goes well increasing the percentage while simultaneously phasing out the old version.

For this we are going to deploy the stable version (blue), introduce a new version and then change the new version until we are happy with it and then increase the traffic to the new version.

Prepare images​

For this lab we need the 2 images (blue and green) we already created in the previous labs. If you haven't created the blue and green images, first complete these 2 labs:

Or you can use public images e.g. nginx:latest and tomcat:latest for this lab.

Create a workload from the Catalog​

Go to the list of Builds and add the repository of the green build to your clipboard.

  1. Go to Workloads in the left menu and click on Create Workload.

  2. Select k8s-deployment-canary from the Catalog.

  3. Add the Name canary for the workload.

  4. Set the Auto image updater to Digest and fill in:

  • imageRepository : paste from the clipboard
  • imageParameter : versionTwo.image.repository
  • tagParameter : versionTwo.image.tag
  1. In the workload values, change the following parameters:
# For the v1 as the stable version
versionOne:
  image:
    repository: # paste from clipboard, but change to blue
    tag: latest
# The v2 as canary with the auto image updater configured
versionTwo:
  image:
    repository: # paste from clipboard. This will be the green image
    tag: latest

  1. Click Submit

  2. Click on Deploy Changes

We now created 2 deployments. One for blue and one for green. The green image (our canary) will be automatically updated after a change (commit).

Expose the service​

  • In the left menu panel under click Services then click on Create Service.

  • Select the canary service.

  • Under Traffic Control click enabled (and use the default weights for v1 and v2).

  • Under Exposure Ingress, select Ingress and use the default configuration.

  • Click Submit.

  • Click Deploy Changes.

See the results​

You will see the canary service in the list of Services. Click on the URL and refresh the page for a couple of times. You should first see:

Team apps

After a refresh of the page you should see:

Team apps

Update the canary image​

Go to the green repo and change the background-color in the green.html file from green to MediumSeaGreen and commit the change. After a couple of minutes you should now see the background color of version 1 (our canary) changed:

Team apps

Do you see the difference?