We just hit it again last night with maas_2.6.1-7832-g17912cdc9-0ubuntu1~18.04.1
2019-10-31-08:28:28 root DEBUG maas root pod compose 1 hostname=vault-1 cores=2 memory=4096 storage=20.0 zone=2 interfaces=eth0:space=oam-space;eth1:space=internal-space,type=bridge
2019-10-31-08:28:29 root ERROR Command failed: pod compose 1 hostname=vault-1 cores=2 memory=4096 storage=20.0 zone=2 interfaces=''eth0:space=oam-space;eth1:space=internal-space,type=bridge''
2019-10-31-08:28:29 root ERROR b'Pod must be on a known host if interfaces are specified.'
We just hit it again last night with maas_2. 6.1-7832- g17912cdc9- 0ubuntu1~ 18.04.1
2019-10-31-08:28:28 root DEBUG maas root pod compose 1 hostname=vault-1 cores=2 memory=4096 storage=20.0 zone=2 interfaces= eth0:space= oam-space; eth1:space= internal- space,type= bridge ''eth0: space=oam- space;eth1: space=internal- space,type= bridge' '
2019-10-31-08:28:29 root ERROR Command failed: pod compose 1 hostname=vault-1 cores=2 memory=4096 storage=20.0 zone=2 interfaces=
2019-10-31-08:28:29 root ERROR b'Pod must be on a known host if interfaces are specified.'