RFE: stop using libvirt's dnsmasq

[fcami]

libvirt's dnsmasq auto-maintains the reverse DNS zone for the virtual network it owns.
Any DHCP lease will be recorded in the reverse DNS zone.
This breaks FreeIPA's automatic DNS reverse zone detection ( freeipa/freeipa#5939 ).

A solution would be to have a BIND instance installed on the ipatests runner, configured with two upstream DNS servers and configure all test runners to use that instance.

[fcami]

Another possibility (rather than configuring a BIND instance) is to configure systemd-resolved to avoid using the parent libvirt dnsmasq. In /etc/systemd/resolved.conf.d/dns_servers.conf:

[Resolve]
DNS=<IP_OF_DNS1> <IP_OF_DNS2>
Domains=~.

[wladich]

I made a check with a VM inside inside vagrant-libvirt:

# hostname -i
fe80::ca85:118d:a8f5:2d43%eth0 192.168.121.181
[root@fedora vagrant]# dig -x 192.168.121.181 @192.168.121.1

; <<>> DiG 9.16.20-RH <<>> -x 192.168.121.181 @192.168.121.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 42825
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;181.121.168.192.in-addr.arpa.	IN	PTR

;; Query time: 0 msec
;; SERVER: 192.168.121.1#53(192.168.121.1)
;; WHEN: Tue Aug 31 12:26:52 UTC 2021
;; MSG SIZE  rcvd: 57

I am not sure if dnsmasq creates or does not create any DNS records for VMs, but anyway it does not return then in DNS requests

[rjeffman]

Under Fedora 36 (cloud image) there is an answer for dig -x.

[root@server ~]# cat /etc/os-release | sed -n "/^NAME=/p;/^VARIANT=/p"
NAME="Fedora Linux"
VARIANT="Cloud Edition"
[root@server ~]# hostname -i
fe80::b873:a31a:d26:8507%eth0 192.168.122.63
[root@server ~]# dig -x 192.168.122.63

; <<>> DiG 9.16.28-RH <<>> -x 192.168.122.63
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34400
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;63.122.168.192.in-addr.arpa.	IN	PTR

;; ANSWER SECTION:
63.122.168.192.in-addr.arpa. 0	IN	PTR	urep.ipa.test.

;; Query time: 1 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Wed May 25 14:41:55 UTC 2022
;; MSG SIZE  rcvd: 83