ReleaseRun · Kubernetes 2026
5 Kubernetes Gotchas That Break Production
Real mistakes, real incident post-mortems, and the fixes that actually work.
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1
Gotcha #1
imagePullPolicy: Always slows every deploy
Every Pod restart hits your registry. On spot instances with high churn this adds 30-60s per restart and can rate-limit your registry.
imagePullPolicy: IfNotPresent # cached image is fine # Always = necessary only if you use :latest or mutable tags # Pin tags: my-app:1.4.0 — then IfNotPresent is safe
2
Gotcha #2
No resource limits = noisy neighbour OOMKills your app
Without limits, one runaway Pod can OOMKill every other Pod on the node. Without requests, the scheduler can't plan and overcommits nodes.
resources: requests: cpu: "100m" memory: "128Mi" limits: memory: "256Mi" # CPU: no limit (throttle not kill) # No CPU limit = throttled, not OOMKilled
3
Gotcha #3
livenessProbe kills app before it finishes starting
livenessProbe starts checking immediately. JVM apps, apps loading ML models, apps running migrations — all get killed in CrashLoopBackOff.
startupProbe: # add this! httpGet: {path: /health, port: 8080} failureThreshold: 30 # 30 × 10s = 5 minutes periodSeconds: 10 livenessProbe: # only starts after startupProbe succeeds httpGet: {path: /health, port: 8080} periodSeconds: 30
4
Gotcha #4
kubectl drain takes down all replicas at once
Node upgrades and cluster maintenance drain nodes. Without a PodDisruptionBudget, kubectl drain can evict ALL pods simultaneously — instant outage.
apiVersion: policy/v1 kind: PodDisruptionBudget metadata: {name: my-app} spec: minAvailable: 2 # always keep 2 pods running selector: matchLabels: {app: my-app}
5
Gotcha #5
StatefulSet PVC stuck Pending — AZ mismatch
Cloud block disks (EBS, Azure Disk) are zone-specific. If PVC is created before the Pod is scheduled, it may land in the wrong AZ and the Pod can never mount it.
apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: {name: gp3} provisioner: ebs.csi.aws.com volumeBindingMode: WaitForFirstConsumer # Waits until Pod is scheduled, then creates disk in same AZ
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