Hi how can I stop a running flow run either with the web ui

Question

Hi how can I stop a running flow run either with the web ui or the cli

Anna Geller · Answer

Assuming you are asking for Prefect 2 0 since you asked about it yesterday you can hit Control + C when running from CLI

Anna Geller · Answer

GIF <https media giphy com media LG4usXVLfNDRSalw3P giphy gif> We don t have the option to kill run from the UI yet this feature may be added later this year but it s hard to do since it requires cancelling resources on a remote infrastructure via an API call which is not always possible

Anna Geller · Answer

An alternative way to kill it would be to list the processes find it and then kill it ```ps ef | grep python kill s SIGTERM PID```

Anna Geller · Answer

or ```ps ef | grep prefect kill s SIGTERM PID```

Anna Geller · Answer

<https discourse prefect io t how to cancel a flow run 376|here> is Discourse topic for 1 0

Tim Helfensdörfer · Answer

Yes 2 0 Ctrl+C is not possible since it is running inside a container remotely without any manual input

Tim Helfensdörfer · Answer

The task itself is not running anymore But it is still marked as Running in the interface

Tim Helfensdörfer · Answer

I understand the remote infrastructure part only partially We are running an agent which is listening on a queue The queue publishes tasks and the agent executes it The same way the queue could publish stop task commands which the agent can stop Maybe it s more complicated But on our server no task is running at the moment but the queue is blocked with a running task which does not exist anymore

Anna Geller · Answer

gt still marked as Running in the interface we have an open issue for it it s on the roadmap I understand your point but this is indeed a bit more complicated than that since there is no concept of a queue in Prefect you can think of a work queue more as a filter for the agent to decide which work to pick up but once the agent did pick up some work and started running it on some remote infra deployed by the flow runner it s not as simple to kill it since Prefect doesn t have access to your infrastructure and can only remotely initialize some action via an API call

Tim Helfensdörfer · Answer

Just for proof that we really have no running jobs on our system So our only option at the moment is to raise the concurrency limit for the queues which are not queues every time a job keeps showing as running Is there a reason for this so we can avoid this in the future

Tim Helfensdörfer · Answer

As a last note on this topic The agent communicates with the api while running a flow for example to send logs to the server orion or for other status notifications Does the task timeout eventually

Anna Geller · Answer

gt which are not queues they are still queues what I meant is that a mental model of a filter makes more sense to understand the inner workings here because a queue can make you think Prefect uses some RabbitMQ SQS or similar system here while to keep Orion lightweight and with a minimal set of dependencies it uses only backend DB and API for that purpose but it works the same way as a queue would

Anna Geller · Answer

I would try to figure out why your job keeps hanging for now Soon there will be an option to mark such run as Completed from the UI I hear you loud and clear the problem you raised is that on your infra side nothing is running but the UI wrongly shows that it is running which we plan to address soon by introducing an option to mark such run as Completed

Tim Helfensdörfer · Answer

Thanks