Re: systemd-resolved and single-label DNS entries

[Chuck Lever <chuck.lever@oracle.com>]

On 8/26/25 10:21 AM, Jeff Layton wrote:
> On Tue, 2025-08-26 at 14:53 +0200, Daniel Gomez wrote:
>> On 26/08/2025 12.58, Jeff Layton wrote:
>>> I'm hitting a problem with NFS testing on kdevops guests. Recently when
>>> I bring up a guest, it's unable to resolve the name of the NFS server
>>> via DNS.
>>
>> FYI, nfstests works fine with Debian testing (forky). Both hosts and guests.
>>
>>
> 
> 
> Thanks. Some questions:
> 
> 1/ did your setup get the entries in /etc/hosts? That seems to be what
> has changed recently. That's not working for some reason.
> 
> 2/ Does forky use systemd-resolved? The problem is clearly there with
> Fedora 42. The DNS server on the virtual bridge works fine:
> 
> ----------------8<-----------------
> $ dig @192.168.122.1 kdevops-nfsd.
> 
> ; <<>> DiG 9.18.33 <<>> @192.168.122.1 kdevops-nfsd.
> ; (1 server found)
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24955
> ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
> 
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 1232
> ;; QUESTION SECTION:
> ;kdevops-nfsd.                  IN      A
> 
> ;; ANSWER SECTION:
> kdevops-nfsd.           0       IN      A       192.168.122.85
> 
> ;; Query time: 0 msec
> ;; SERVER: 192.168.122.1#53(192.168.122.1) (UDP)
> ;; WHEN: Tue Aug 26 10:18:47 EDT 2025
> ;; MSG SIZE  rcvd: 57
> 
> $ resolvectl query kdevops-nfsd.
> kdevops-nfsd.: 'kdevops-nfsd.' not found
> ----------------8<-----------------
> 
> It seems like we're doing something "unseemly" by putting bare names in
> DNS like this, given that systemd-resolved won't pass them along.
> 
> Since systemd-resolved will only resolve bare names without a domain
> using LLMNR, we should either take steps to make that work, or fix it
> so that systemd-resolved will forward the requests (by setting up a
> proper domain name and setting up the search path in the resolver).
> 

"won't pass them along" -- does that depend on the settings in
/etc/nsswitch.conf ?


-- 
Chuck Lever