How to fix Exit Code 143 (SIGTERM) in Kubernetes

Exit code 143 is normal during these operations:

# Check recent events
kubectl get events --sort-by='.lastTimestamp' | grep <pod-name>

# See what triggered termination
kubectl describe pod <pod-name>

If the pod was terminated during a deployment, scale operation, or node maintenance, exit code 143 is expected and correct.

Ensure your application handles SIGTERM for graceful shutdown:

Python:

import signal

def shutdown_handler(signum, frame):
    print("SIGTERM received, shutting down gracefully...")
    # Close database connections
    # Finish processing current requests
    # Flush logs and metrics
    sys.exit(0)

signal.signal(signal.SIGTERM, shutdown_handler)

Node.js:

process.on('SIGTERM', async () => {
  console.log('SIGTERM received, starting graceful shutdown');
  await server.close();
  await db.disconnect();
  process.exit(0);
});

If your application needs more time to shut down gracefully:

spec:
  terminationGracePeriodSeconds: 60  # Default is 30
  containers:
  - name: app
    image: myapp:latest

During this period:
1. SIGTERM is sent to the container
2. Application has time to complete cleanup
3. If not terminated, SIGKILL is sent after grace period

Add a preStop lifecycle hook for cleanup without code changes:

lifecycle:
  preStop:
    exec:
      command: ["/bin/sh", "-c", "sleep 10 && /app/cleanup.sh"]

The preStop hook runs before SIGTERM is sent, giving additional time for:
- Draining connections from load balancers
- Completing in-flight requests
- Deregistering from service discovery

Exit code 143 is healthy; watch for these patterns instead:

Concerning:
- Exit code 137 (SIGKILL) - forced kill, possibly OOM
- Frequent terminations outside of deployments
- Short-lived pods constantly receiving SIGTERM

Check if eviction is the cause:

kubectl describe pod <pod-name> | grep -A 5 "Status:"
kubectl top pod <pod-name>  # Check resource usage

Eviction due to resource pressure may indicate undersized limits.

Verify your application actually completes graceful shutdown:

# Watch logs during termination
kubectl logs -f <pod-name>

# Delete and observe shutdown
kubectl delete pod <pod-name>

Look for your shutdown messages in logs. If the pod terminates with 143 but logs show incomplete cleanup, your grace period may be too short or shutdown logic has issues.