Importance of Graceful Shutdown in Kubernetes
a day ago
- #Zero-Downtime Deployments
- #Graceful Shutdown
- #Kubernetes
- Graceful shutdown in Kubernetes is crucial for zero-downtime deployments, but rolling updates alone are insufficient.
- Pods can be terminated for various reasons like scaling, node maintenance, or resource constraints, leading to dropped requests if not handled properly.
- Kubernetes sends a SIGTERM signal to terminate pods, followed by SIGKILL if the pod doesn't exit within the grace period (default 30 seconds).
- Most applications don't handle SIGTERM properly, causing in-flight requests to be dropped, especially problematic for long-running operations.
- Testing showed a basic service dropped 2% of requests during updates, while a graceful service handled all requests without errors.
- Key steps for graceful shutdown include listening for SIGTERM, tracking in-flight requests, separating health checks, and configuring Kubernetes properly.
- Proper shutdown handling improves user experience, prevents cascading failures, and boosts deployment confidence.
- Implementing graceful shutdown patterns allows for frequent deployments without impacting users.