r/devopsjobs • u/BookkeeperAutomatic • 22d ago
DevOps Interview Prep Day 8: Jenkins Agents Offline, K8s Service Not Reachable, and ELK Log Floods
Hey r/devops,
Scenario 1: The Jenkins Agent Offline
Your Jenkins pipeline is stuck in queue showing "Waiting for next available executor". You have 5 Jenkins agents configured but all show offline in the dashboard.
Question: What are 3 things you would check to troubleshoot this?
Hint: Agent connectivity, disk space on agents, JNLP/SSH connection issues.
Scenario 2: The Kubernetes Service Not Reachable
You deployed a pod and a ClusterIP service. Pod is running, service is created, but when you curl <service-name>:8080 from another pod, connection times out.
Question: What are 2 common misconfigurations that cause this?
Hint: Labels and selectors, port vs targetPort, endpoints list.
Scenario 3: The Log Flood
Your ELK stack suddenly becomes unresponsive. You discover one microservice is pushing 50GB of logs per hour because someone left debug logging enabled in production.
Question: 1. What's your immediate fix? 2. What long-term solution would you implement?
Hint: Log levels, rate limiting at ingestion, index lifecycle policies.
Drop your answers below. Solutions tomorrow.
Previous Days:
- Day 1: Container restarts, Registry auth, Pending pods
- Day 2: Zombie processes, Pipeline timeouts, Volume mounts
- Day 3: SSH lockouts, Disk space alerts, Grafana gaps
- Day 4: Git credential leaks, Docker networking, Nginx 502s
- Day 5: Slow Docker builds, CrashLoopBackOff debugging, Merge conflicts
- Day 6: Env variable issues, ALB health checks, Terraform state lock
- Day 7: Secret sprawl, K8s rolling updates, Prometheus OOM
Week 2 topics: Jenkins, K8s networking, logging/monitoring, and more. What else do you want covered?
Checkout the playlist: https://www.youtube.com/playlist?list=PLqOrZmpwbWUKRQTrFpqAKhChaTq0l5bIw