False positive on "External DHCP server(s) discovered on interface" with multiple MAAS units

[Nobuto Murata]

maas 2.7.1-8262-g.9a49af7df-0ubuntu1~18.04.1

Let's say you have two rackd on the same network and those two are set as the primary and secondary rack controller respectively for a VLAN.

$ maas root vlan read fabric-0 0
Success.
Machine-readable output follows:
{
    "vid": 0,
    "mtu": 1500,
    "dhcp_on": true,
    "external_dhcp": null,
    "relay_vlan": null,
    "fabric": "fabric-0",
    "name": "untagged",
    "secondary_rack": "SECONDARY_ID",
    "primary_rack": "PRIMARY_ID",
    "space": "oam-space",
    "fabric_id": 0,
    "id": 5001,
    "resource_uri": "/MAAS/api/2.0/vlans/5001/"
}

Then, both rack controllers report that there is an external DHCP server each other. The expected result is that the line can say that it's another DHCP server on the network, but managed by MAAS or something.

[rackd.log on primary]
2020-07-03 13:36:27 provisioningserver.rackdservices.dhcp_probe_service: [info] Probe for external DHCP servers started on interfaces: broam.
2020-07-03 13:36:37 provisioningserver.dhcp.detect: [info] External DHCP server(s) discovered on interface 'broam': 10.X.X.X
2020-07-03 13:37:18 provisioningserver.rackdservices.dhcp_probe_service: [info] External DHCP probe complete.

[rackd.log on secondary]
2020-07-03 13:34:47 provisioningserver.rackdservices.dhcp_probe_service: [info] Probe for external DHCP servers started on interfaces: broam.
2020-07-03 13:34:57 provisioningserver.dhcp.detect: [info] External DHCP server(s) discovered on interface 'broam': 10.Y.Y.Y
2020-07-03 13:35:37 provisioningserver.rackdservices.dhcp_probe_service: [info] External DHCP probe complete.

[Alberto Donato (ack)]

Hi, to clarify, are you seeing a wrong behavior from maas, or is this just about the messaging being unclear?

[Nobuto Murata (nobuto)]

No, there was no obvious wrong behavior from MAAS. It's just nice to be fixed.

[Jerzy Husakowski (jhusakowski)]

Works as intended, the logs show the DHCP servers detecting each other.