Hibernate/Wake-Up Clusters

[vlerenc]

Story

• As user/operator I want to hibernate clusters, so that I can save costs when I don't need the clusters anymore/temporarily.

Motivation

See gardener/gardener#50 in which the required Gardener functionality was implemented.

Acceptance Criteria

• Cluster can be scaled down to 0 machines across all pools and up again

Implementation Proposal

We can either do nothing (basically only do #23, which we like to do anyways) and leave it to the user to find out that by scaling down all pools manually he can effectively hibernate a cluster or we can offer some convenience function in the dashboard that does that across all pools, clearly labeled "Hibernate". The reverse operation, "Wake-Up", is harder, but maybe the former pool sizes could be written as annotations into the shoot resource by the dashboard, in which case "Wake-Up" would know how to scale up again.

Definition of Done

• Knowledge is distributed: Have you spread your knowledge in pair programming/code review?
• Unit Tests are provided: Have you written automated unit tests or added manual NGPTT tickets?
• Integration Tests are provided: Have you written automated integration tests?
• Minimum API exposure: If you have added public API, was it really necessary/is it minimal?
• Operations guide: Have you updated the operations guide?

[petersutter]

prerequisite: gardener/gardener#191

[ghost]

Just as an idea: What about giving an operator the possibility to hibernate certain clusters based on time, eg. hibernate all dev-clusters at 10.00 pm and wake them up the following day at 07.00am.

[petersutter]

Brainstorming
We could add something like that to the cluster creation dialog which is enabled by default for evaluation- and development-purpose clusters and the gardener controller is taking care for the auto-sleep

[petersutter]

Allow auto-hibernation/wake-up configuration in Shoot specification - gardener/gardener#348