Rollout Stuck
384 incident problems that show up as “Rollout Stuck”.
Read first
When the ConfigMap changed but the Pod keeps using the old valuesAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when values don't refresh after a ConfigMap update because of envFrom, subPath, volume projection, or rollout trigger differences.Kubernetes3 min readWhen CoreDNS is Running but only DNS lookups failAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when the CoreDNS Pod looks healthy but failures occur in the kube-dns path, upstream, node-local-dns, or policy.Kubernetes3 min readWhat to check first when CrashLoopBackOff appearsAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when a Pod restarts repeatedly and the real cause is left in the previous logs and events.Kubernetes3 min read
Recommended problems
Reviewed problems first, then problems with detailed scenarios.
CICD-001Finding the real failure point in GitHub Actions build logsA training scenario for isolating the true cause from logs where npm dependency conflicts and cache traces are mixed together.ReviewedCI/CDIntermediate20 minFreeCICD-002Recovering a container deployment where the latest tag blocks rollbackCovers how to redesign a safe rollback structure in a pipeline that has no image versioning strategy.ReviewedCI/CDAdvanced25 minProCICD-009Deployment failingA scenario that narrows down the root cause, centered on checking the permission-policy difference by event type, in the situation of a deployment failing because the secret is empty only on tag releases.ReviewedCI/CDIntermediate21 minFreeCICD-031GITHUB_TOKEN read-only default blocks release provenance uploadThe workflow can build and test successfully, but the release job fails when it tries to publish attestations or update release metadata with a narrower token scope.ReviewedCI/CDIntermediate21 minProCICD-038Publish workflow never startsA formatting or version-bump workflow commits successfully, but the downstream publish workflow never runs because the triggering push used the repository token.ReviewedCI/CDBeginner16 minFreeCICD-064Helm post-upgrade hook Job never completes and blocks the release promotion gateThe chart renders correctly, but the deployment never settles because a hook job keeps restarting and Helm treats the upgrade as unfinished.ReviewedCI/CDIntermediate20 minFree
All problems (384)
ImagePullBackOff: new pods cannot pull the release imageImagePullBackOff: new pods cannot pull the release image is a hands-on troubleshooting drill. Read the pull event to see what the registry could not find. container-startup needs to be checked by narrowing scope, recent change, and the current live signal before rollback. 실무에서...ReviewedKubernetesBeginner3 minFreeCICD-009Deployment failingA scenario that narrows down the root cause, centered on checking the permission-policy difference by event type, in the situation of a deployment failing because the secret is empty only on tag releases.ReviewedCI/CDIntermediate21 minFreeCICD-103Helm post-renderer strips readiness probes from the canary manifest and Argo CD approves a broken rolloutThe application renders cleanly, but the post-processing step removes health checks from just the canary variant so progressive delivery never sees a meaningful gate.ReviewedCI/CDIntermediate18 minFreeCICD-001Finding the real failure point in GitHub Actions build logsA training scenario for isolating the true cause from logs where npm dependency conflicts and cache traces are mixed together.ReviewedCI/CDIntermediate20 minFreeCICD-064Helm post-upgrade hook Job never completes and blocks the release promotion gateThe chart renders correctly, but the deployment never settles because a hook job keeps restarting and Helm treats the upgrade as unfinished.ReviewedCI/CDIntermediate20 minFreeK8S-008New workloads not schedulingA scenario that narrows down the root cause, centered on comparing the schedule conditions with the actual node labels, in the situation of new workloads not scheduling because node affinity is too strong.ReviewedKubernetesIntermediate21 minFreeCICD-038Publish workflow never startsA formatting or version-bump workflow commits successfully, but the downstream publish workflow never runs because the triggering push used the repository token.ReviewedCI/CDBeginner16 minFreeK8S-016After changing the Deployment selector, the ReplicaSet cannot grab the new PodsAfter changing the Deployment selector, the ReplicaSet cannot grab the new... is a hands-on troubleshooting drill. An introductory problem for understanding selector immutability and label strategy in declarative resources. Kubernetes Config and Rollouts needs to be checked by...KubernetesBeginner15 minFreeCICD-098Maven cache reuse hides a repository auth failure until the monthly cache eviction windowBuilds appear stable for weeks, then all fail at once because the dependency cache had been masking a broken repository credential path.CI/CDIntermediate15 minFreeNETWORK-072LACP bundle never forms after a stack replacementCabling is correct, but the upstream sees a different partner identity and refuses to aggregate the links into the expected bundle.NetworkIntermediate16 minFreeLINUX-089rsync backup over SSH stallsNetwork reachability is fine, but the batch backup never starts because the negotiated SSH crypto overlap disappeared during a hardening change.LinuxIntermediate16 minFreeNETWORK-107DHCP relay uses the correct helper address but the source interface belongs to the wrong VRF so replies never returnDiscover messages leave the switch, yet offers vanish because the server replies into a routing context that has no path back to the client segment.NetworkIntermediate17 minFreeNETWORK-079OSPF virtual link stays downArea IDs still look familiar, but the virtual link cannot form because the transit area assumptions were broken during a partial topology cleanup.NetworkIntermediate17 minFreeNETWORK-068Port-channel min-links keeps the bundle down after a partial member failureOne physical path still forwards traffic, but the logical interface remains down because the configured minimum bundle size is no longer satisfied.NetworkIntermediate17 minFreeCICD-095Release branch hotfix bypasses the migration stepThe deployment is green, but the hotfix runs against an old schema because the branch-specific trigger skipped the migration workflow.CI/CDIntermediate17 minFreeNETWORK-084Spanning-tree guard blocks one hypervisor uplinkThe network configuration is stable, but a host starts sending unexpected bridge protocol units and the protection feature shuts the access port down.NetworkIntermediate17 minFreeCICD-056CloudFront invalidation runs before the new asset manifest is fully publishedThe deployment pipeline clears the CDN correctly, but users still receive broken bundles because the invalidation precedes the final asset upload and manifest sync.CI/CDIntermediate18 minFreeNETWORK-080MAC flapping alarms appearThe network is stable, but one mobile workload triggers MAC move alarms and intermittent forwarding loss because the switching design assumes slower host movement.NetworkIntermediate18 minFreeCICD-030Release note generation fails on shallow clone runnersRelease note generation fails on shallow clone runners is a hands-on troubleshooting drill. A changelog step depends on full git history, but shallow checkout settings hide the required tags and commits. GitHub GitHub Actions Workflows needs to be checked by narrowing scope, r...CI/CDIntermediate18 minFreeLINUX-091Tmpfs mount survives the deploy but vanishes after rebootThe application worked during the change window, then failed after restart because the critical mount existed only as a temporary runtime action.LinuxIntermediate14 minFree