Troubleshoot Apache ZooKeeper

When to use this skill

• Quorum Loss: Network partition or >50% node failure prevents writes. The
• Write Pipeline Stall: Transaction log disk saturation (fsync latency spikes).
• GC Pause Cascade: JVM Stop-the-World GC freezes the process. Clients miss
• Session Expiration Storm: Leader failover or network event causes mass session
• Heap Exhaustion / OOM: Cumulative znode growth, unbounded watches, or session
• Snapshot/Recovery Stall: Large DataTree makes snapshot creation CPU-intensive
• Any time the user reports a Apache ZooKeeper service behaving outside its expected envelope (elevated errors, latency, saturation, resource exhaustion, or unexpected restarts).
• An on-call engineer is paging on a Netdata alert tied to a Apache ZooKeeper instance and wants a structured triage path.

Key facts