[Ayush4958]

Description

When new nodes join the cluster with readiness.k8s.io/* taints, critical Infra DaemonSets (network & storage driver) can't schedule on them without explicit tolerations. This causes a deadlock where node can't become ready until those drivers run

I had added automatic toleration injection for DaemonSets without requiring a separate webhook server:

• Controller keeps a list of active readiness taints in a ConfigMap
• Kubernetes MutatingAdmissionPolicy reads list & automatically add the missing tolerations to DaemonSets when they are created / updated
• Existing tolerations are preserved without duplication & workloads can opt out using the annotation readiness.k8s.io/auto-tolerate: false
• If the policy or configmap is missing daemonsets are admitted normally without being blocked

Related Issue

Closes #7

Type of Change

/kind feature

Testing

• Automated Tests: make test passed across all packages
• Static Checks: ./hack/verify-all.sh passed
• Helm Validation: helm lint & template rendering verified
• Cluster Test: Verified on a Kubernetes v1.36 KinD cluster that DaemonSets receive tolerations automatically & opt out annotations are respected

Checklist

• make test passes
• make lint passes

Does this PR introduce a user-facing change?

Auto tolerate DaemonSets against readiness taints using Kubernetes MutatingAdmissionPolicy

Generative AI Usage Disclosure

• No AI tools were used
• AI tools were used

How they were used:
AI assisted with drafting the CEL expressions, helm templates and unit tests. All changes, failure modes, and test results were reviewed, debugged, and verified locally on kind by myself

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[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Ayush4958
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[kubernetes-prow]

Hi @Ayush4958. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work.

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[Ayush4958]

Hi @Karthik-K-N
Please take time to review it
Thanks ..

[Karthik-K-N]

/ok-to-test

[kubernetes-prow]

@Ayush4958: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-node-readiness-controller-scale-test-binary-1000-continuous	69a302a	link	true	/test pull-node-readiness-controller-scale-test-binary-1000-continuous

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.