Uninterruptible Sleep State (D State) in Kubernetes
Why processes enter D state, how unhandled storage timeouts block container cleanup, and how to debug kernel waits on worker nodes.
- 10 min read - openshift, kubernetes, linux
Topic
kubernetes
Run Jobs Sequentially in OpenShift 4.18
Run Jobs sequentially in OpenShift 4.18: plain Jobs, initContainers, a chained CronJob, then an Argo Workflow where each step waits for the last.
- 12 min read - openshift, kubernetes, jobs
What is Network Policy in Kubernetes
What Kubernetes Network Policy is, how pod selectors and ingress rules work, and how default-deny isolates traffic between your workloads.
- 6 min read - kubernetes, network-policy, security
K9s: Terminal UI for Kubernetes Clusters
How to use K9s to inspect cluster state, stream pod logs, troubleshoot failing workloads, and navigate Kubernetes resources without repetitive kubectl commands.
- 6 min read - kubernetes, k9s, cli
Catalog Unreachable With Green Pods
Pods were Ready and endpoints were populated, yet the storefront got connection refused. A NetworkPolicy allowed the wrong pod label on the wrong port.
- 10 min read - kubernetes, troubleshooting, network-policy
Waybill API Down: Four Broken Layers
Four stacked Kubernetes faults: unschedulable pods, a missing Secret key, a failing sidecar readiness probe, and a Service selector matching nothing.
- 10 min read - kubernetes, troubleshooting, scheduling
Payments API Down While Pods Are Ready
Pods were 1/1 Ready, yet the API failed. Debugging two hidden Kubernetes faults: a mismatched Service targetPort and a Secret with a trailing newline.
- 7 min read - kubernetes, troubleshooting, services
Pod Is Running but Not Ready
A storefront pod was 0/1 Running with an inaccessible frontend. Troubleshooting a failing readiness probe configured for a non-existent /healthz endpoint.
- 7 min read - kubernetes, troubleshooting, readiness-probe
The Pod That Refused to Be Edited
A tale of a Pending Pod, an immutable nodeSelector, and the scheduler's hidden gate.
- 7 min read - kubernetes, troubleshooting, scheduling