@Marvin I am deploying a flow with a CRON schedule in a Docker container. However, the flow runs when the container is first started – even if it is not within the CRON's schedule. How do I fix this?

Unfortunately, I couldn't find any relevant issues on GitHub that directly address the problem of a CRON schedule triggering a flow run upon container startup in Prefect 2.x. However, this is a common issue that can occur with scheduling systems, and there are a few general strategies you can consider to avoid running a flow outside its CRON schedule when starting a container: 1. Initial Check: Amend the startup script of your container to check if the current time is within the CRON schedule before firing off the flow. This can be done via a small script that parses the CRON time and compares it with the current time. 2. CRON Job Internal: Instead of triggering the flow run at the container startup, you can use a CRON job within the container that aligns with your desired schedule. 3. Prevent Immediate Execution: Ensure that there isn't any configuration within Prefect or the entrypoint script that's causing the flow to run immediately. Sometimes, workflows are configured to run upon registration or deployment, so check for that. 4. External Scheduler: Another approach is to have an external scheduler manage the runs, which is detached from the container lifecycle. The scheduler will only trigger the flow to run when it's supposed to. 5. Container Orchestration: If you're using an orchestrator like Kubernetes, you might consider using its scheduling features rather than running CRON within the container. Kubernetes CronJobs, for example, can be more flexible and reliable for this purpose. Since this appears to be a more intricate issue, it might be helpful to post a question on Prefect's community Slack channel or GitHub with details of your setup for targeted advice from the Prefect community. Would you like to try another search, or do you need assistance with anything else related to Prefect?

This might not be it at all (and I might be misunderstanding) but do you happen to invoke the flow run function in the code that is running in the container?

@flow
def my_func():
   ...

my_func() # <-- will run on import

@flow
def my_func()
   ...

if __name__ == '__main__':
  my_func() # <-- won't run on import

🚨 exactly that jake – just found that after marvin told me to double check my code in point 3 😭 I'm defining a flow in one script and importing it to execute in another. I.e,

# flow.py
@flow
def my_func():
   ...

my_func() # I still had this line in the code from development

Then

# execute.py
from flow import my_func

if __name__ == '__main__':
  my_func.serve(cron="blah")

Guess that lingering

my_func()

in

flow.py

was inadvertently kicking it off immediately before returning to a scheduled format.