Comment 0 for bug 1695083

The MAAS rack discovered a new interface bridge (lxdbr0). After the discovery of such bridge, MAAS created a new Fabric/VLAN/Subnet (e.g. fabric-5/untagged/10.10.10.0/24). After the discovery,

That said, I was providing DHCP from fabric-3/untagged which has two subnets 10.90.90.0/24 and 192.168.100.0/24.

After restarting the rack controller, the "ntp-servers" configuration in DHCP was updated pointing to the IP address of the lxdbr0. You can see this as:

shared-network vlan-5002 {
    subnet 10.90.90.0 netmask 255.255.255.0 {

           ignore-client-uids true;
           next-server 10.90.90.1;
           option subnet-mask 255.255.255.0;
           option broadcast-address 10.90.90.255;
           option domain-name-servers 10.90.90.1;
           option domain-name "maas";
           option routers 10.90.90.254;
           option ntp-servers 10.10.10.1;

    }
    subnet 192.168.100.0 netmask 255.255.255.0 {

           ignore-client-uids true;
           next-server 192.168.100.5;
           option subnet-mask 255.255.255.0;
           option broadcast-address 192.168.100.255;
           option domain-name-servers 10.90.90.1;
           option domain-name "maas";
           option ntp-servers 10.10.10.1;
    }
}

To revert it back, two things were tried:

Removing 'lxdbr0'

1. Remove 'lxdbr0'
2. restart maas-rackd
3. ntp-servers option was updated accordingly.

Changing newly created VLAN to a different L2 space

1. Added a new L2 space (test).
2. Moved fabric-5/untagged to 'test' space.
3. restarted maas-rackd.

This updated the configuration of dhcpd to have the correct NTP server.

That said, what seems to be happening:

1. MAAS using the IP of a different subnet (in a different fabric/vlan) for NTP because it is in the same space.
2. Trigger that would have updated the config automatically in the event of a space change.