Fixes single-upstream DNS brittleness on non-DHCP hosts. Each host now
has a primary internal resolver + external fallback (AdGuard) so DNS
keeps working if the primary resolver IP is unreachable.
New config:
- Proxmox host (192.168.1.127): plain /etc/resolv.conf with
nameserver 192.168.1.2 (pfSense LAN) + 94.140.14.14 (AdGuard).
Previously: single nameserver 192.168.1.1 — could not resolve
internal .lan names at all. Documented in
docs/runbooks/proxmox-host.md.
- Registry VM (10.0.20.10): systemd-resolved drop-in at
/etc/systemd/resolved.conf.d/10-internal-dns.conf
(DNS=10.0.20.1, FallbackDNS=94.140.14.14, Domains=viktorbarzin.lan)
plus matching per-link nameservers in /etc/netplan/50-cloud-init.yaml.
Previously: 1.1.1.1 + 8.8.8.8 only — image pulls referencing .lan
hostnames would fail to resolve. Documented in
docs/runbooks/registry-vm.md.
- TrueNAS (10.0.10.15): host unreachable during this session
("No route to host" on 10.0.10.0/24). Deferred best-effort per
WS F instructions; noted on the beads task.
Both hosts have pre-change backups at /root/dns-backups/ for
one-command rollback. Fallback behaviour was validated by routing
each primary to a blackhole and confirming dig answered from the
fallback.
Both runbooks include the verified resolvectl / resolv.conf state,
the fallback-test procedure, and the rollback steps.
Closes: code-dw8
