Limit Stack Names to 42 Characters to Prevent StatefulSet Label Value crashes

[mateusvtt]

Problem Description

The operator currently allows stack names of any length, which can lead to Kubernetes validation errors when those names are used to generate StatefulSet resources. This occurs because:

1. The stack name plus the string "-workspace" is used for the StatefulSet name
   

   pulumi-kubernetes-operator/operator/internal/controller/pulumi/stack_controller.go

   Line 1320 in f01d73c

   func nameForWorkspace(stack *metav1.ObjectMeta) string {

   
   

   pulumi-kubernetes-operator/operator/internal/controller/auto/workspace_controller.go

   Line 430 in f01d73c

   return w.Name + "-workspace"

2. The StatefulSet name is then used in the controller-revision-hash label, see StatefulSet may need specical method of generating pod name  kubernetes/kubernetes#79337
3. The full label value ends up exceeding Kubernetes' 63-character limit
   Example error:

statefulset/my-very-long-stack-name-for-staging-environment-workspace create Pod my-very-long-stack-name-for-staging-environment-workspace-0 in StatefulSet my-very-long-stack-name-for-staging-environment-workspace failed error: Pod "my-very-long-stack-name-for-staging-environment-workspace-0" is invalid: metadata.labels: Invalid value: "my-very-long-stack-name-for-staging-environment-workspace-6888c94d69": must be no more than 63 characters

This will silently fail, and the error can be found in the event logs.

Root Cause

When creating StatefulSets, the operator:

1. Appends "-workspace" to the stack name to create the StatefulSet name
2. Kubernetes automatically adds a "-" suffix (10 characters) to the StatefulSet's pods for the controller-revision-hash label
3. The total suffix length is 21 characters ("-workspace-" = 11 chars + hash = 10 chars)

Given Kubernetes' 63-character limit for label values, this means the original stack name must not exceed 42 characters (63 - 21 = 42).

Example

Just create any Stack name with more than 42 chars.

Output of pulumi about

Does not apply.
pulumi-kubernetes-operator:v2.0.0

Additional context

No response

Contributing

It's possible to avoid the issue with this simple validation:
https://github.com/pulumi/pulumi-kubernetes-operator/compare/master...mateusvtt:pulumi-kubernetes-operator:set-stackname-limit?expand=1
It's kinda of a breaking change, however I believe no one is able to create a Stack with more than 42 chars.

[EronWright]

This is a pretty common issue with Kubernetes operators, since children tend to be named after their parent. I agree with adding the length validation, thanks!