Prevent Spring Boot application closing until all current requests are finished

You could increase the terminationGracePeriodSeconds, the default is 30 seconds. But unfortunately, there's nothing to prevent a cluster admin from force deleting your pod, and there's all sorts of reasons the whole node could go away.

We did a combination of the above to resolve our problem.

• increased the terminationGracePeriodSeconds to the absolute maximum we expect to see in production
• added livenessProbe to prevent Traefik routing to our pod too soon
• introduced a pre-stop hook injecting a pause and invoking a monitoring script:
  1. Monitored netstat for ESTABLISHED connections to our process (pid 1) with a Foreign Address of our cluster Traefik service
  2. sent TERM to pid 1

Note that because we send TERM to pid 1 from the monitoring script the pod will terminate at this point and the terminationGracePeriodSeconds never gets hit (it's there as a precaution)

Here's the script:

#!/bin/shwhile [ "$(/bin/netstat -ap 2>/dev/null | /bin/grep http-alt.*ESTABLISHED.*1/java | grep -c traefik-ingress-service)" -gt 0 ]do  sleep 1donekill -TERM 1

Here's the new pod spec:

containers:  - env:    - name: spring_profiles_active      value: dev    image: container.registry.host/project/app:@@version@@    imagePullPolicy: Always    lifecycle:      preStop:        exec:          command:          - /bin/sh          - -c          - sleep 5 && /monitoring.sh    livenessProbe:      httpGet:        path: /actuator/health        port: 8080      initialDelaySeconds: 60      periodSeconds: 20      timeoutSeconds: 3    name: app    ports:    - containerPort: 8080    readinessProbe:      httpGet:        path: /actuator/health        port: 8080      initialDelaySeconds: 60    resources:      limits:        cpu: 2        memory: 2Gi      requests:        cpu: 2        memory: 2Gi  imagePullSecrets:  - name: app-secret  serviceAccountName: vault-auth  terminationGracePeriodSeconds: 86400

Try to Gracefully Shutdown your Spring Boot Application.

This might help :

https://dzone.com/articles/graceful-shutdown-spring-boot-applications

This implementation will make sure that none of your active connections are killed and application will gracefully wait for them to finish before the shutdown.