Machine interfaces allow '_' character, results on a interface based domain breaking bind (as it doesn't allow it for the host part).

Hi Wojtek,

Do you happen to have any reference about NIC naming? It seems wrong to me that linux would allow you to add NICs with the '_'.

That said, I don't agree with having a global option to change the behavior of this, provided that just leads to confusion and not the best experience. My inclination would be to simply prevent users from creating interface names that include the '_' character.

Hi Andres,
I'm often changing interface name in linux to vlan name (not number) or similar. It is not limitation of linux. In linux you can use _ in interface name without problem, it works also with maas. When you configure interface with underscore character, maas properly configure interface names in netplan and interfaces will work properly in linux.
Problem is limitation of domain names. According to https://tools.ietf.org/html/rfc1035 only letters, digits and - character is only allowed.
I assume that in linux for interface name it is possible to use the same characters as for file names.

According to my situation I simply change naming convention and I'm not using _ characters in interface names any more, but it is new project so it is not problem to me.
For me global option to change naming behavior is not necessary. From other side maybe someone uses underscore in interface names because linux allow and it will be problem when you release new version of maas with underscore limitation.
In my opinion if you do not want to add global option better will be replace underscore character to another or remove it when generating domain names.

--
Regards,
Wojtek

I have also encountered this bug.
Maas kept adding docker_gwbridge interface to the zone config.

Adding "check-names master ignore;" to named.conf.options helped to circumvent the issue.

I've also got this with 2.7.0 with a snap install.

Is there an easy way to add the "check-names master ignore;", or is this fixed in the 2.8 beta?

So, we ran into this today. Is there any kind of plan to fix this, other than ignoring faulty records in zone files generated by MAAS?

If I could get a pointer on where to start looking I might be able to hack together a merge request with a fix, but I haven't looked much at the MAAS code base as of yet.

Just realised @Tiago already did the work back in December. Thanks! Let's hope it gets merged soon!

MAAS bug-council,

This is desired on MAAS 3.0.

If the MR to 3.4 is approved, can we send backport MRs to 3.3 and 3.2 (currently maintained by MAAS Eng) ? We'd follow with 3.1 and 3.0 releases later (maintained by SEG, at the moment).

Thanks!

The user will upgrade to MAAS 3.1, thus marking 3.0 as Won't Fix.

MAAS bug-council,

My patch seems ready and without any outstanding reviews. Do you need anything else from me on this?

Thank you!

The issue is on track to be released, thank you for your contribution!

Hello Tiago, or anyone else affected,

Accepted maas 3.1.2 into ppa:maas/3.1-next and snap:3.1/edge
(code version 3.1.2-10926-g.5ad7060e5).

Please test this update and provide your feedback on this bug:

If it fixes the bug for you, please add a comment mentioning the version you tested and what testing has been performed, and change the tag from verification-needed-maas-3.1 to verification-done-maas-3.1.

If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-maas-3.1.

Thank you in advance for helping!

The update will be released after the bug(s) have been verified and quality assurance testing is successful.

Verification done on maas 3.1.

Installed from ppa:maas/3.1-next, enlisted and commissioned a system ("free-parrot") with _two_ network interfaces in the subnet (as the 1st/PXE network interface does not get a PTR record with its name), and clicked 'Actions -> Edit Physical' and set their names to 'nic_one' (1st/PXE) and 'nic_two_test' (2nd/non-PXE), and clicked 'Deploy', which immediately updates the bind zone config.

The PTR record for network interface 'nic_two_test' (with underscores) is 'nic-two-test' (without underscores).

# maas admin machines read | jq '.[0] | .fqdn, ( .interface_set[] | .name, .links[].ip_address )' -r
free-parrot.maas
nic_one
10.0.0.7
nic_two_test
10.0.0.8

# grep free-parrot /etc/bind/maas/zone.0.0.10.in-addr.arpa
7 30 IN PTR free-parrot.maas.
8 30 IN PTR nic-two-test.free-parrot.maas.

# apt-cache policy maas
maas:
  Installed: 1:3.1.2-10926-g.5ad7060e5-0ubuntu1~20.04.1
  Candidate: 1:3.1.2-10926-g.5ad7060e5-0ubuntu1~20.04.1
  Version table:
 *** 1:3.1.2-10926-g.5ad7060e5-0ubuntu1~20.04.1 500
        500 http://ppa.launchpad.net/maas/3.1-next/ubuntu focal/main amd64 Packages
        100 /var/lib/dpkg/status

MAAS 3.1.2 has been released:
- deb: ppa:maas/3.1 (1:3.1.2-10926-g.5ad7060e5-0ubuntu1~20.04.1 )
- snap: 3.1/stable (3.1.2-10926-g.5ad7060e5)