Networking

Introduction: When All Else Fails, Layer by Layer This week, I found myself knee-deep in troubleshooting Grafana Labs telemetry containers that refused to start properly in an OpenShift cluster (loki, mimir, prometheus, tempo, otel collector, spring boot services, etc.). The workloads looked good, the containers were running, but the telemetry data simply wouldn’t flow. Sound familiar? After hours of fruitless searching and even getting blocked by AI assistance (yes, even Claude couldn’t crack it), I realized I was in need of applying long learned principles. That’s when I decided to document the mental framework I developed over years of debugging network issues. ...

Introduction In Kubernetes clusters, pods rely on DNS resolution to communicate with other services and external resources. By default, pods use a DNS system within the cluster that operates with private addresses and the domain cluster.local. The DNS server responsible for this resolution is CoreDNS. Many applications are configured by default for standard Kubernetes setups, which can cause DNS resolution issues when deployed in OpenShift environments. Understanding how CoreDNS works and how to properly configure applications for OpenShift is crucial for ensuring reliable service discovery and communication. ...

Learn about CIDR notation, IP addressing, and subnetting in modern computer networking. This comprehensive guide covers the basics, benefits, and practical examples of Classless Inter-Domain Routing.