DevOps RealWorld Series #2 Ephemeral Storage: The Hidden Cause of CI/CD Failures in Kubernetes

We encountered a strange issue where build agents were failing randomly While running Jenkins pipelines on Kubernetes. Agent pods would start normally and builds would run successfully for some time. Then the pods would terminate unexpectedly, causing pipeline failures. Initially, we investigated: • Jenkins logs • Pipeline configuration • Docker build stages • SonarQube scans Everything looked normal. The real cause became clear after inspecting pod events: kubectl describe pod jenkins-agent-pod The Events section showed: Evicted The node was low on resource: ephemeral-storage What Consumes Ephemeral Storage in CI Agents? CI agent pods often consume more disk than expected due to: • Docker image layers • Dependency downloads • Temporary build files • Test artifacts • Coverage reports • SonarQube cache • Package manager caches Unlike CPU and memory, ephemeral storage is frequently ignored in resource configuration. Why This Causes Pipeline Failures? When ephemeral storage usage exceeds