Comment 3 for bug 1629142

>1. DHCP was enabled for the VLAN
Here is evidence from the our Jenkins job, that DHCP was enabled:
2016-09-29-21:23:54 INFO 'maas maas vlan update fabric-0 untagged dhcp_on=true primary_rack=gckmmf'
2016-09-29-21:23:56 INFO {
    "mtu": 1500,
    "id": 5001,
    "dhcp_on": true,
    "vid": 0,
    "name": "untagged",
    "secondary_rack": null,
    "external_dhcp": null,
    "fabric": "fabric-0",
    "primary_rack": "gckmmf",
    "resource_uri": "/MAAS/api/2.0/vlans/5001/"
}
2016-09-29-21:23:56 INFO
2016-09-29-21:23:56 DEBUG {
    "name": "untagged",
    "vid": 0,
    "dhcp_on": true,
    "mtu": 1500,
    "primary_rack": "gckmmf",
    "external_dhcp": null,
    "resource_uri": "/MAAS/api/2.0/vlans/5001/",
    "id": 5001,
    "secondary_rack": null,
    "fabric": "fabric-0"
}
>2. The UI shows DHCP is active
Yes, in the UI DHCP was listed as enabled. I also tried disabling and then re-enabling DHCP.
>3. Have you waited a few to see if the rack start dhcp ? there's some situations in which the rack will wait a few seconds to start DHCP.
Yes, the server had been running for many minutes, while we investigated. I also manually tried restarting maas-rackd.service and then maas-dhcpd.service (e.g. sudo systemctl restart maas-rackd)