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#prefect-server
Title
# prefect-server
l

Luiz Felipe

05/12/2022, 6:53 PM
Hello! I'm running a Prefect Server on K8s and instantiating a Dask cluster to run my flows. It seems to be working well (the flow finishes successfully), but it is not storing the task logs on the UI. Is there any way to guarantee it is going to be there? When I've added a
sleep(60)
before the end of the task, the task logs appeared, but without it it does not work.
k

Kevin Kho

05/12/2022, 7:05 PM
Are you using a dask kubernetes cluster?
l

Luiz Felipe

05/12/2022, 7:08 PM
Yes, I'm using the KubeCluster class. This is my flow:
Copy code
with Flow(
    "Dask Kubernetes Flow",
    storage=storage,
    executor=DaskExecutor(
        cluster_class=lambda: KubeCluster(make_pod_spec(image=prefect.context.image)),
        adapt_kwargs={"minimum": 2, "maximum": 3},
    ),
    run_config=KubernetesRun(),
) as flow:
One of my flows task calls logger.info() to write a message, but it does not appear on the UI normally
k

Kevin Kho

05/12/2022, 7:23 PM
Did this work before? Because Dask logs really don’t show in the UI
l

Luiz Felipe

05/12/2022, 7:25 PM
Oh, I see. This is something I'm trying this week, so I cannot say if it has worked before. Is there any reason that adding a sleep() on my task made so that the log appeared on the UI?
k

Kevin Kho

05/12/2022, 7:28 PM
No I don’t at the moment. I wonder if it’s related to this. (Though the issue is for local). Maybe you can chime in there?
l

Luiz Felipe

05/12/2022, 7:53 PM
Sure, thanks. One last question, is there an easy way that people normally use to aggregate the logs of the clusters directly from K8s? I thought of using the
get_logs
method of KubeCluster, but given that Prefect is creating the cluster and then deleting them after running, I won't be able to run the command
k

Kevin Kho

05/12/2022, 7:56 PM
Could you do it in Python mid run? Like you could use a state handler?
l

Luiz Felipe

05/12/2022, 8:45 PM
I see. I'll explore this approach and try to make something work. Thanks a lot!
@Kevin Kho Is there any reason that, by adding a
time.sleep()
on my tasks, most of the logs appeared on the Server UI? If there is some hacky way to force them to always appear it would really work for me.
k

Kevin Kho

05/13/2022, 6:25 PM
No I am clueless about that at this time. Is it consistent (adding 60 seconds works every time)? Could you have a server time and flow time that are out of sync?
l

Luiz Felipe

05/13/2022, 6:54 PM
It seems it doesn't have to be just 60secs. But I have to add it on all my tasks I want to log currently. I've added a 5secs sleep on each of them and I got a lot more logs onto the UI
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