Create example config for Vertical Pod Autoscaler

[dak1n1]

Description

I'm working on creating an example using GKE and Vertical Pod Autoscaler (VPA). This issue tracks work in progress.

Potential Terraform Configuration

I have part of it done here, but it needs more work:

• GKE cluster with VPA enabled (working)
• Example app utilizing VPA (not working)

References

Non-blocking bugs encountered during testing:

• Namespaces must be explicitly specified in each resource Provider fails to create resource if namespace is not specified #48
• Resource dependency isn't working Resource dependency doesn't work #52

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[dak1n1]

Here are more details about failing to create the VPA object:

$  terraform apply --auto-approve
kubernetes_manifest.deployment_redis_master: Refreshing state...

Error: rpc error: code = Unknown desc = update dry-run for 'default/redis-vpa' failed: admission webhook "gke-vpa.k8s.io" does not support dry run

Full debug trace here: https://gist.github.com/dak1n1/396b30f1503c69f1a0f42091d8e45ee5

I thought this indicated a server-side apply issue at first, but I was able to server-side apply the same objects using yaml:

$ kubectl apply -f redis.yaml --server-side
verticalpodautoscaler.autoscaling.k8s.io/redis-vpa serverside-applied
deployment.apps/redis-master serverside-applied

It only appears to be an issue during the server-side dry-run:

$ kubectl apply -f redis.yaml --server-dry-run
deployment.apps/redis-master created (server dry run)
Error from server (BadRequest): error when creating "redis.yaml": admission webhook "gke-vpa.k8s.io" does not support dry run

I found that if I edit the MutatingWebhookConfiguration for VPA, I can get this to apply:

$ kubectl edit mutatingwebhookconfiguration gke-vpa-webhook-config

I changed sideEffects: Unknown to sideEffects: None. Then it worked.

$ kubectl apply -f redis.yaml --server-dry-run
verticalpodautoscaler.autoscaling.k8s.io/redis-vpa created (server dry run)
deployment.apps/redis-master created (server dry run)

However, I'm not sure yet what the impacts of that change are, and how we might want to approach this in the example.

[dak1n1]

Since the upstream project has added sideEffects: None to the controller, this seems like a safe change to make in this example app too. kubernetes/autoscaler#2278