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Rightsize Resource Requests from Metrics

Read the 95th percentile CPU and memory from metrics and set requests to p95 so pods are not throttled or over-provisioned.

~25 minkubernetesresourcesrightsize

Task

Configure kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi so the cluster enforces the policy at admission time instead of relying on manual review.

When to use this

A developer deploys a pod without kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi and it disrupts a node, causing evictions on a production cluster.

Prerequisites

  • A Kubernetes cluster with kubectl access
  • Cluster admin or namespace edit RBAC

Steps

1. Configure kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi in the project configuration file with the recommended defaults.

kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi

Expected output: The configuration is accepted and kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi runs without errors on the first invocation.

2. Run the check locally to verify kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi produces the expected result before pushing.

pnpm test

Expected output: Local run matches CI behavior; no surprises after push.

3. Add the gate to the CI pipeline so kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi blocks merge on failure.

- name: Run add resource request limit rightsize
  run: pnpm test

Expected output: Pull requests with failing kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi are blocked from merging.

Troubleshooting

Problem

The check passes locally but fails in CI

Solution

Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.

Problem

Configuration is rejected with a schema error

Solution

Check the tool version matches the config schema; older versions may not support newer fields.

Limitations

  • The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
  • Configuration drift is possible if someone edits settings outside version control.

Enforce at admission

Start by measuring the problem. Read the 95th percentile CPU and memory from metrics and set requests to p95 so pods are not throttled or over-provisioned. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run kubectl set resources deploy/api –requests=cpu=200m,memory=256Mi –limits=cpu=500m,memory=512Mi against the current codebase and inspect the output before wiring it into CI.

kubectl set resources deploy/api --requests=cpu=200m,memory=256Mi --limits=cpu=500m,memory=512Mi

Verify the policy

Once the gate is in place, make failures actionable. A failing kubectl set resources deploy/api –requests=cpu=200m,memory=256Mi –limits=cpu=500m,memory=512Mi should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.