Gardener: Workers count is limited by cloud-config Secret size limit

[ialidzhikov]

What happened:
Currently it is not possible to have more than 20-25 (depending on the OS) workers in .spec.provider.workers.

How to reproduce it (as minimally and precisely as possible):

1. Create a Shoot with 25 Worker entries under .spec.provider.workers.

1. Ensure that the Deploying managed resources step fails with:

status:
  lastErrors:
  - description: 'task "Deploying managed resources" failed: retry failed with context
      deadline exceeded, last error: Secret "managedresource-shoot-cloud-config-execution"
      is invalid: data: Too long: must have at most 1048576 characters'
    lastUpdateTime: "2020-04-09T11:08:27Z"
    taskID: Deploying managed resources

Anything else we need to know?:

Environment:

• Gardener version: v1.2.0
• Kubernetes version (use kubectl version):
• Cloud provider or hardware configuration:
• Others:

[aylei]

I'd like to help with this

[ialidzhikov]

Yep, sure. I didn't start any work on this.

[rfranzke]

Any ideas how to fix it? Having a dedicated MR+secret per worker pool?

[aylei]

Any ideas how to fix it? Having a dedicated MR+secret per worker pool?

Yes, the test is a little delayed because I don't have v1.2.1 cluster running so I have to create a new one. But I can open a draft PR to show the basic idea.

[rfranzke]

No worries, take your time, just wanted to check back. Thanks for picking it! :)