MAAS fails to fetch datasource from metadata_url missing port

Hey everyone!

I spent some time trying to setup a MAAS server using the Ansible playbook. While the playbook works great (kudos!), I ran into an interesting issue when trying to use an external DHCP server.

I know that this is not necessarily a supported configuration nonetheless, I got my nodes to PXE boot. Only once Cloud-init kicks in, I am seeing an error (see screenshot attached). Basically saying it can’t reach the meta-data/instance-id endpoint. The problem here is that the port number seems to be missing. When querying the endpoint on my machine and adding port number 5248 I get the expected answer.

Checking the http://10.8.8.31:5248/MAAS/metadata/latest/enlist-preseed/?op=get_enlist_preseed endpoint the metadata_url value is also missing the port.

datasource:
  MAAS:
    metadata_url: http://10.8.8.31/MAAS/metadata/

But http://10.8.8.31:5240/MAAS/metadata/latest/enlist-preseed/?op=get_enlist_preseed returns the correct metadata url.

datasource:
  MAAS:
    metadata_url: http://10.8.8.31:5240/MAAS/metadata/

It seems roughly related to bug #1982315 which should have been resolved in version 3.3.0 when using external DNS. So maybe the root cause is not external DHCP but rather the external DNS? Do you have any tips and pointers on how to further troubleshoot this or resolve it?

Also found another user having similar issues in the forums: https://discourse.maas.io/t/maas-enlistment-with-external-dhcp-server-is-failing-with-url-helper-py-error-timed-out-no-response-from-urls/7173

Thanks!

MAAS Release: 3.3.4-13189-g.f88272d1e
Install Method: Snap
DHCP: External
Device: UEFI Bare Metal