WebService construct advanced example

Advanced WebService construct example

It includes:

Two sets of objects:
- One for the live deployment,
- One for the canary deployment.
An environment variable to control the deployment's stage.
Auto-scaling for the live deployment.
An Nginx container that serves the application and patches cookies to include SameSite.

Usage

In order to synthesize the example to Kubernetes YAML, you need to set the CANARY_STAGE environment variable to one of the following values:

base - two sets of objects are created (live and canary) and are completely separate (i.e. live load balancer only serves live deployment and same with canary).
canary - only the canary deployment is applied so you can update its version.
post-canary - as above and also the live service's selector is updated to include both deployments, so load balancer will serve both versions.
full - both deployments are updated to the new version and the live service serves from both deployments.

Once you choose the stage, you can run the command like so:

CANARY_STAGE=full npx cdk8s synth

This will produce dist/app.k8s.yaml file which you can then apply to your cluster:

kubectl apply -f dist/app.k8s.yaml

You can then try changing the release version and apply the canary stage:

RELEASE=v0.2.2 CANARY_STAGE=canary npx cdk8s synth
kubectl apply -f dist/app.k8s.yaml

You can run the tests with the following command:

npm test -- examples/advanced-web-service