Radar Tool Diagnoses Kubernetes Network Misconfigs Before Traffic Fails

A common Kubernetes misconfiguration — where a Service's targetPort does not match the container's actual port — can make a cluster appear fully healthy while traffic silently fails. To address this, developers built a Reachability feature in a tool called Radar that reconstructs the Kubernetes path from Ingress to Service to pods using static analysis before sending any network probes. Radar checks selector matches, endpoint existence, pod readiness, and port alignment against its own informer cache, flagging mismatches without firing live traffic. When live probing is needed, Radar runs DNS, TCP, TLS, and HTTP checks from multiple vantage points — including the user's machine, the API-server proxy, and a temporary in-cluster Job — and reports each result with its specific context rather than a generic 'reachable' status. The tool also surfaces the underlying kubectl commands behind its findings, allowing engineers to verify or reproduce the diagnosis independently without treating it as a black box.