Q: What is the difference between liveness and readiness probes? Give a scenario where each is important.
- Liveness probe — "is this container still alive?" If it fails, Kubernetes restarts the container. Use for detecting deadlocks or infini...
#Kubernetes #Advanced Scenarios #L2 #Container Orchestration #K8s
🎙️ Candidate Opening & Architectural Context
""Kubernetes is a declarative desired state system; understanding the reconciliation loop is how you diagnose this quickly. When addressing this question, I walk the interviewer through our production incident runbook: isolating the blast radius, checking diagnostic logs and metrics, and applying a safe fix.""
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🛠️ Production Runbook & Step-by-Step Resolution
1️⃣
Initial Diagnostics & Root Cause Analysis
Key: failed liveness = restart. Failed readiness = remove from load balancer rotation, but don't restart.
- Liveness probe — "is this container still alive?" If it fails, Kubernetes restarts the container. Use for detecting deadlocks or infinite loops where the process is running but not making progress.
- Scenario: A Java app has a thread deadlock. The JVM is running but requests hang forever. Liveness probe detects no HTTP response → restarts container.
- Readiness probe — "is this container ready to serve traffic?" If it fails, the pod is removed from Service endpoints. Use for apps that need warmup time or temporarily can't serve (e.g., during a DB connection retry).
2️⃣
Remediation & Permanent Safeguards
- Scenario: App just started and is loading a 5GB ML model. Readiness fails until load completes. No traffic is sent yet. App is not restarted (liveness probe is fine).
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Pro-Tip: Liveness probe — "is this container still alive?" If it fails, Kubernetes restarts the container. Use for detecting deadlocks or i."
⚡ 60-Second Elevator Pitch Talking Points
- Liveness probe — "is this container still alive?" If it fails, Kubernetes restarts the container....
- Scenario: A Java app has a thread deadlock. The JVM is running but requests hang forever. Livenes...
- Readiness probe — "is this container ready to serve traffic?" If it fails, the pod is removed fro...
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