Hi We're facing a persistent scheduling issue for Metaflow flows deployed with

@schedule

to our modern Argo Workflows cluster. The core problem is a schema incompatibility in the generated Argo CronWorkflow manifest. Key Issue: Singular vs. Plural Fields 1. Metaflow Output: Metaflow is generating the CronWorkflow using the deprecated singular field:

spec.schedule: '*/15 * * * *'

(a string). 2. Argo Controller Requirement: Our Argo Controller (v3.6+) *r*equires the current plural field:

spec.schedule*s*: ['*/15 * * * *']

(a list). 3. The Failure: As a result, the Argo Controller sees an empty list (

schedules: []

) and throws the error:

"cron workflow must have at least one schedule"

.

We should be able to address this quickly (today). It’s something that we have been tracking.

I'll take a look right now. I assume we also want to still support argo < 3.6 ?

@thankful-ambulance-42457 thank you for the analysis!, we found our controller is running the image tagged quay.io/argoproj/workflow-controller:latest. We are currently working to pin the exact version number.

could you also try to either redeploy an existing scheduled flow, or a test flow with a schedule to see if the manifest is created correctly with the new plural schedules?

Version 3.7.3 didn’t resolve the issue. I redeployed the workflow, and it’s still the same issue

oh that's odd. I'm wondering what the difference in our setup is. Are you deploying the argo resources with a helm chart or something else? I'm testing this out with the local

metaflow-dev

setup and unable to reproduce the issue, which is a bit baffling.

@thankful-ambulance-42457 We identified a critical version mismatch as the root cause and have now aligned both the Argo Server and Workflow Controller to v3.7.3. This resolved the validation error, and scheduled flows are running correctly. Now the controller handles the deprecated singular schedule field automatically, allowing scheduling to work as expected. I really appreciate your time and support in pinpointing the issue in our environment.

@boundless-sugar-55740 could you also check what version of argo-workflows-server you are running? the schedule->schedules conversion seems to be tied to its api, but I was still not able to get any failures with the older one either

yep xD !

out of curiosity, which version of the argo-server were you running? I'll still poke around a bit to see if I can get my setup to break in the same way

it was the latest version as well

oh as in the

latest

tag? seems to break for my setup as well, excellent.