Fix ImagePullBackOff · ErrImagePull: Diagnose the Cause from Events and Finish with Copy-Paste
Pinpoint kubectl ImagePullBackOff and ErrImagePull in five minutes with an Events-message diagnosis table. A hands-on guide that fixes imagePullSecrets namespace issues, private registry auth, Docker Hub rate limits, and ECR token expiry wi
Istio/Ingress Networking Failures: Finding the Root Cause in Traffic-Split and Path-Matching YAML
A practical guide to solving complex networking problems—traffic routing errors, path matching failures, and more—when using Istio and Ingress in a microservices environment. Lock in operational stability with essential YAML examples and an
Kubernetes NetworkPolicy: A Hands-On Guide to Zero Trust Service Communication Control
A complete, practice-oriented guide to Kubernetes NetworkPolicy that closes security gaps in MSA environments at the root. It covers core principles, Ingress/Egress YAML implementation, and a Default Deny strategy based on least privilege.
Istio vs NetworkPolicy: Precedence When L3/L4 and L7 Policies Conflict
When service mesh adoption makes networking policy more complex, which rule actually wins if Istio and Kubernetes NetworkPolicy collide? This guide hierarchically analyzes L3/L4 vs. L7 policy precedence and presents practical architecture b
When a Kubernetes L7 Network Policy Doesn't Apply: An eBPF (Cilium) Debugging Workflow
When HTTP header-based L7 network policies fail in Kubernetes, simply re-applying them will not fix the problem. This guide analyzes eBPF vs. iptables, diagnoses three policy-failure pitfalls, and presents a practical debugging workflow usi
Kubernetes Ingress Controller: Nginx vs Traefik — A Practical Guide to Choosing the Right One for Your Environment
A deep technical comparison of Nginx Ingress and Traefik, covering auto-discovery, rate limiting, and other core features. Includes selection criteria aligned with your team's operating philosophy and practical tuning tips.
Istio Communication Errors: A Practical Debugging Guide to Finding Root Causes with a 5-Step Checklist
Istio communication errors in a microservices environment are notoriously hard to pin down. This guide diagnoses complex issues involving sidecars, VirtualServices, DestinationRules, and more with a practical 5-step checklist—from basic con
From Terraform to K8s: A Practical End-to-End DevOps CI/CD Roadmap (IaC & GitOps)
Learning individual technologies isn't enough. This guide walks through a practical, step-by-step roadmap: laying the infrastructure foundation with Terraform, deploying applications with Kubernetes, and completing the full CI/CD pipeline w
Kubernetes Network Latency: A Segment-by-Segment Runbook from DNS and kube-proxy to MTU and eBPF
Find the cause of Kubernetes service-to-service latency by measuring each segment: DNS (ndots, 5-second delays), kube-proxy mode, overlay MTU, NetworkPolicy and sidecars. Symptom triage table, copy-paste commands, and eBPF tools.
Kubernetes Secrets Management: Vault vs AWS Secrets Manager Comparison and Optimal Architecture Guide
Beyond the limits of native K8s Secrets, this guide lays out a Zero Trust secrets-management strategy. It compares HashiCorp Vault and AWS Secrets Manager in depth and walks through production-ready architectures, including the sidecar patt
Kubernetes Service Discovery Principles: From How CoreDNS Works to Headless Services
In Kubernetes, inter-service communication hinges on finding the right address. This guide takes a deep dive into how CoreDNS works, the relationship between Services and Endpoints, and the differences between ClusterIP and Headless Service
Analyzing K8s 5xx Errors: A 7-Step Debugging Guide for Ingress/Gateway API
5xx errors in Kubernetes are among the hardest to diagnose. This guide presents a 7-step checklist for systematically diagnosing complex networking failures at the Ingress/Gateway API layer, with advanced debugging logic you can apply immed