In a recent production incident, a three-node Nacos cluster faced a severe cascade failure after a single node was restarted due to hardware issues. Despite the cluster's inherent support for node failover, the restart triggered a wave of unhealthy service alerts, leading to widespread service restarts. The root cause was not the node failure itself but how the brief server-side jitter propagated to clients, causing a snowball effect. This incident underscores the importance of robust client-side resilience, including proper retry logic, connection pooling, and health check timeouts. It also highlights the need for thorough testing of failover scenarios and the implementation of circuit breakers to prevent cascading failures. For teams relying on Nacos or similar service discovery tools, this case serves as a valuable reminder that distributed systems require careful attention to both server and client configurations to ensure overall stability.
A production Nacos cluster with three nodes experienced a cascade failure when one node was restarted, causing widespread service health check failures and restarts. This highlights critical lessons in distributed systems design.