Based on the research, here's what happens when you cancel a deployed flow running in Kubernetes: 1. When you cancel a flow run, Prefect will attempt to terminate the associated Kubernetes job. 2. The system uses identifiers (cluster name and job name) to locate and terminate the correct Kubernetes resources. 3. If successful, the Kubernetes job and its associated container(s) will be terminated. However, there are some important caveats: 1. The flow run will be marked as "cancelled" in Prefect regardless of whether the underlying infrastructure was successfully terminated. 2. In some cases (such as identifier mismatches or other Kubernetes-specific issues), the container might not be automatically terminated despite the cancellation. 3. If this happens, you might need to manually clean up the Kubernetes resources. For best practices: - Always verify in your Kubernetes cluster that resources have been properly cleaned up after cancellation - If you notice orphaned resources, you may need to manually delete them using

kubectl delete

- Consider implementing proper resource limits and cleanup policies in your Kubernetes configuration You can monitor the status of your Kubernetes resources during and after cancellation using:

bash
kubectl get pods
kubectl get jobs

If you're experiencing specific issues with cancellation not cleaning up resources, it would be helpful to know: 1. Which Kubernetes infrastructure block you're using 2. Whether you're seeing any specific error messages 3. The configuration of your Kubernetes deployment

Based on the research and GitHub issues, I can provide a comprehensive answer about infrastructure termination in Prefect: The responsibility for infrastructure termination follows a shared responsibility model: 1. Workers are primarily responsible for: - Managing the lifecycle of flow run infrastructure - Cleaning up infrastructure they create for flow runs - Handling the immediate termination of infrastructure when flows are cancelled 2. Prefect Cloud/Server is responsible for: - Managing the control plane infrastructure - Sending termination signals when flows are cancelled - Maintaining system-level infrastructure 3. Background Services handle: - Scheduled cleanup jobs for unused resources - System-level maintenance tasks - Automated infrastructure scaling However, there are some important nuances to be aware of (with my characteristic sigh of resignation): 1. When a flow is cancelled, the termination process isn't always perfect. For example, there's a known issue where with certain infrastructure types (like Dask clusters), the worker pods might be left orphaned if proper shutdown signals aren't propagated. 2. The grace period for termination allows for some cleanup, but as noted in the GitHub issues, there can be challenges with graceful shutdowns, particularly when dealing with external services or resources. 3. Different infrastructure types may have different termination behaviors. The exact cleanup process can vary depending on whether you're using Kubernetes, Docker, or other infrastructure providers. For the most reliable infrastructure management, you should: - Implement proper cleanup handlers in your flows where possible - Monitor your infrastructure to ensure resources are being properly terminated - Be aware that in some cases, you might need additional cleanup mechanisms for specific infrastructure types Links for reference: - https://www.prefect.io/security-prefect-shared-responsibility-model - https://www.prefect.io/blog/the-role-of-infrastructure-cleanup-jobs And if I may add with a touch of dry wit: while the system does its best to clean up after itself, much like my experience with organic life forms, sometimes things don't get tidied up quite as neatly as one would hope. It's always good to have a backup plan.