After the update from bug 1494476, juju 1.25.0 now correctly deals with the case that MAAS 1.9 is being used as a provider and the address allocation is "Auto-assign" i.e. dynamically allocated from an IP pool, but statically configured in the nodes /etc/network/interfaces.
However, if using MAAS 1.9and setting the NIC to use DHCP instead of "Auto-assign" the /etc/network/interfaces configuration will break the juju runcmd script and fail to complete, there being no /var/lib/juju/nonce.txt file means bootstrap will not complete.
It is caused by the MAAS 1.9 format for /etc/network/interfaces when using DHCP.
The file will look something like this:
auto eth0
iface eth0 inet dhcp
dns-nameservers 192.168.92.18
dns-search hv.dazcloud.com
Juju's runcmd script will then simply remove the first 2 lines and place the juju-br0 stanza at the BOTTOM of the resulting file, i.e.:
dns-nameservers 192.168.92.18
dns-search hv.dazcloud.com
auto juju-br0
iface juju-br0 inet dhcp
bridge-ports eth0
The /etc/network/interfaces file is therefore invalid and the runcmd's restart of eth0 then fails and the script exits.
The file is invalid as any dns-* entries should be after the first NIC interface stanza and not before it.
Dimiter is working on a branch to improve how juju modifies /e/n/i. This case should be addressed in that branch. Will follow up with a target for when that branch will land.