Resolvd /
resolvd
resolvd(8) was added in OpenBSD 6.9. This daemon manages /etc/resolv.conf by automatically adding nameservers from various sources such as dhcpleased(8), iked(8), slaacd(8), and other network devices.
Nameservers can also be manually added using route(8)'s nameserver command.
Troubleshooting
Sometimes you may need to manually edit resolv.conf(5) because resolvd(8) is receiving incorrect nameserver information. This can happen if your DHCP server is providing an incorrect DNS server (or simply a DNS server you don't want to use).
If you make an edit to resolv.conf(5) and find the edits are not persisting, it is likely that resolvd(8) is overwriting your changes.
You can turn off resolvd(8):
# rcctl disable resolvd # rcctl stop resolvd
Now edits to /etc/resolv.conf
should persist.