SysAdmin

A quick fix for the ’not enough storage available’ error when running jstack on Windows, caused by the JVM running under the Local System Account. Two workarounds using Psexec or JMX remote monitoring.

A practical guide to backing up and restoring the etcd key-value database in a Kubernetes cluster. Covers snapshot-based and file-based backup methods, integrity checks, and static pod manifest updates.

A step-by-step guide to upgrading a Kubernetes cluster using kubeadm, covering control plane and worker node upgrades. Includes the full sequence from version planning through final verification.

A practical guide to using the jcmd and jstack utilities for collecting thread dumps, heap data, and CPU information from a running JVM process. Includes ready-to-use scripts and one-liners for troubleshooting slow or hung Java applications.

Learn how to assign Kubernetes pods to specific nodes at creation time and how to reassign running pods using Binding objects. Covers scheduler behavior and common pitfalls that leave pods stuck in Pending state.

A practical guide to JSON Path syntax, operators, and filters, with hands-on examples for extracting data from JSON documents and Kubernetes resources via kubectl.