How does k8s keeps track of all past revisions?

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1

Curiosity topic here :slight_smile:

Reading the Efficient detection of changes section, I was wondering how k8s can keep track of all past resource’s versions/changes.

Docs says:
These changes itemize the outcome of operations (such as create, delete, and update) that occurred after the resourceVersion you specified as a parameter to the watch request.

Meaning that k8s knows the full resource version at any time in the past.

Did k8s save a full snapshot after any received PUT/PATCH request? Maybe a diff?

If anybody knows the magic behind this, or the actual source file inside the repo that does that, thank you much!

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Not to be too general, but it is stored within the etcd database for the cluster.

As an example you can see the details with kubectl rollout history deployments - feel free to add kube-system or another namespace with any deployments. Hope that helps

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