03 - Enabling DHCP for MAAS

MAAS: Install ~ Configure ~ DHCP ~ Commission ~ Deploy ~ jq ~ SSH ~ More jq

Enabling DHCP for MAAS with the CLI

Of course, the whole point here is to get machines deployed. The next step is to get DHCP working, which means I have to find the untagged VLAN. In truth, it shouldn't be too hard, because at this point, there still should only be one.

In order to turn on DHCP, I need to know two things besides the VLAN name ("untagged"): I need to know the fabric ID and the primary rack controller name. Actually, to start with, all the fabrics will be on the same untagged VLAN, so any fabric will do. In turn, I can find a valid fabric ID by reading it from any subnet, so I'll just pick one I know (192.168.123.0/24, the subnet for my virtual bridge). That means I can find a usable fabric ID like this:

stormrider@wintermute:~$ maas admin subnet read 192.168.123.0/24 | grep fabric_id "fabric_id": 2,

Then I need to find the name of the primary rack controller. I think it's going to be my laptop hostname, but for purposes of argument, I'll assume that I don't know it and get it this way:

stormrider@wintermute:~$ maas admin rack-controllers read | grep hostname | cut -d '"' -f 4 wintermute

So this would mean I should be able to turn on DHCP like this:

stormrider@wintermute:~$ maas admin vlan update 2 untagged dhcp_on=True primary_rack=wintermute {"dhcp_on": ["dhcp can only be turned on when a dynamic IP range is defined."]}

Hmm. I need to define a dynamic IP range for this to work. Well, given that my virtual bridge is on 192.168.123.0/24, I think I'll just use that subnet, so let me choose, say, 192.168.123.190 to 192.168.123.253:

stormrider@wintermute:~$ maas admin ipranges create type=dynamic start_ip=192.168.123.190 end_ip=192.168.123.253

The result of this command is:

Success. Machine-readable output follows: { "subnet": { "name": "192.168.123.0/24", "description": "", "vlan": { "vid": 0, "mtu": 1500, "dhcp_on": false, "external_dhcp": null, "relay_vlan": null, "fabric": "fabric-2", "primary_rack": null, "name": "untagged", "id": 5003, "space": "undefined", "secondary_rack": null, "fabric_id": 2, "resource_uri": "/MAAS/api/2.0/vlans/5003/" }, "cidr": "192.168.123.0/24", "rdns_mode": 2, "gateway_ip": null, "dns_servers": [], "allow_dns": true, "allow_proxy": true, "active_discovery": false, "managed": true, "id": 4, "space": "undefined", "resource_uri": "/MAAS/api/2.0/subnets/4/" }, "type": "dynamic", "start_ip": "192.168.123.190", "end_ip": "192.168.123.253", "user": { "is_superuser": true, "username": "admin", "email": "admin@admin.com", "is_local": true, "resource_uri": "/MAAS/api/2.0/users/admin/" }, "comment": "", "id": 1, "resource_uri": "/MAAS/api/2.0/ipranges/1/" }

Okay, now let's try that DHCP switch-on one more time:

stormrider@wintermute:~$ maas admin vlan update 2 untagged dhcp_on=True primary_rack=wintermute

Now I get something more like I'd like:

Success. Machine-readable output follows: { "vid": 0, "mtu": 1500, "dhcp_on": true, "external_dhcp": null, "relay_vlan": null, "fabric": "fabric-2", "space": "undefined", "primary_rack": "8dwnne", "secondary_rack": null, "name": "untagged", "fabric_id": 2, "id": 5003, "resource_uri": "/MAAS/api/2.0/vlans/5003/" }

It says success, and when I look at the UI? Yes, indeed, DHCP is enabled. Okay, let's see if I can get some machines commissioned.