[2.1b1] Unable to commission nodes in MAAS 2.1, no external route provided

Can you confirm:

1. DHCP is up and running.
2. Can you confirm that dhcpd.conf has gateway definitions (/var/lib/maas/dhcpd.conf).
3. Can you try to manually DHCP from MAAS and see if it gets the correct network information ?

So the issue seems to be that by default, MAAS is not setting a
default gateway. It picked up two fabrics:

Fabric-1 was the internal 10.0.0.0/8 network and has a gateway of 10.0.0.1.
Fabric-2 was the external 192.168.0.0/24 network and MAAS did not set
a gateway for that, as it was an unmanaged network.

With 2.1, while it detected and set up the 10.0.0.0 network, it didn't
set a gateway of 10.0.0.1 for that network, hence a lot of issues in
enlistment and commissioning.

After I manually added a gateway via the UI, I am now able to
commission nodes because they are being set with the gateway route.

Here's the interesting bits of dhcpd.conf before and after:

subnet 10.0.0.0 netmask 255.0.0.0 {
           ignore-client-uids true;
           option subnet-mask 255.0.0.0;
           option broadcast-address 10.255.255.255;
           option domain-name-servers 10.0.0.1;
           option domain-name "maas";
           option ntp-servers 10.0.0.1;

           default-lease-time 600;
           max-lease-time 600;
           #
           # Subnet DHCP snippets
           #
           pool {
              range 10.0.2.0 10.0.3.254;
           }
    }

And here's after setting the gateway via the UI:
subnet 10.0.0.0 netmask 255.0.0.0 {
           ignore-client-uids true;
           option subnet-mask 255.0.0.0;
           option broadcast-address 10.255.255.255;
           option domain-name-servers 10.0.0.1;
           option domain-name "maas";
           option routers 10.0.0.1;
           option ntp-servers 10.0.0.1;

           default-lease-time 600;
           max-lease-time 600;
           #
           # Subnet DHCP snippets
           #
           pool {
              range 10.0.2.0 10.0.3.254;
           }
    }

So the issue seems to just be that MAAS is not telling nodes to use
the MAAS Server as the default gateway automatically, I'm having to
manually enter the MAAS server's IP. I'm guessing this has something
to do with changes to how racks are handled, so maybe it should
default to the IP of the rack controller (which in my case is the maas
server).

also, please check if you set a gateway for the subnet wher ethe dynamic range is.

I am unable to reproduce this. On a fresh installation of MAAS 2.1, my networks where discovered correctly (including gateway_ip). Enabling DHCP set the routers option in the dhcpd.conf for the subnet, and enlisting machines are able to access my router to access the archive.

If you could provide exact steps on how to reproduce this that would be great.

I'm not able to reproduce it now either, and I've tried three times (on VMs).

The original steps I took were:

Start with a working and in-use 2.0 server
Upgrade to 2.0.
Delete nodes
Re-enlist nodes
** New nodes failed to set power type because they couldn't talk to archive.ubuntu.com
Manually set power type
Commission a node
** Commission failed because node couldn't talk to archive.ubuntu.com

That's when I SSH'd to the node and ran route -n and discovered no gateway was set. Which led me to checking the network config in the UI and noticing that for that subnet, there was no gateway set.

I'm starting to think that maybe I just had a bum upgrade and some things didn't happen that should have, because I've not been able to reproduce any of the issues I saw when I upgraded my server, and I've tried recreating these issues several times at this point.