DNS Record Types¶

Supported DNS record types and their behavior in external-dns-unifios-webhook.

Supported Types¶

Type	Supported	Notes
A	Yes	IPv4 address records
AAAA	Yes	IPv6 address records
CNAME	Yes	Canonical name records
TXT	Yes	Text records (no TTL support)

Record Details¶

A Records¶

IPv4 address records.

annotations:
  external-dns.alpha.kubernetes.io/hostname: app.example.com
  external-dns.alpha.kubernetes.io/target: 10.0.0.1
  external-dns.alpha.kubernetes.io/ttl: "300"

Multi-target (Round Robin):

annotations:
  external-dns.alpha.kubernetes.io/hostname: app.example.com
  external-dns.alpha.kubernetes.io/target: "10.0.0.1,10.0.0.2"

Creates separate DNS records for each target, enabling round-robin DNS.

AAAA Records¶

IPv6 address records.

annotations:
  external-dns.alpha.kubernetes.io/hostname: app.example.com
  external-dns.alpha.kubernetes.io/target: "2001:db8::1"

CNAME Records¶

Canonical name records pointing to another hostname.

annotations:
  external-dns.alpha.kubernetes.io/hostname: www.example.com
  external-dns.alpha.kubernetes.io/target: app.example.com

Limitations

Wildcard CNAME (*.example.com) not supported
Duplicate CNAME records for same name not supported
These are dnsmasq limitations

TXT Records¶

Text records for verification and metadata.

annotations:
  external-dns.alpha.kubernetes.io/hostname: _verify.example.com
  external-dns.alpha.kubernetes.io/target: "verification-token"

No TTL Support

UniFi API does not support TTL for TXT records. TTL annotations are ignored.

TTL Behavior¶

Default TTL¶

Default TTL is 300 seconds (5 minutes).

Custom TTL¶

Set TTL via annotation:

annotations:
  external-dns.alpha.kubernetes.io/ttl: "600"

TTL Limitations¶

Record Type	TTL Support
A	Yes
AAAA	Yes
CNAME	Yes
TXT	No

Record Ownership¶

external-dns uses TXT records to track ownership:

_externaldns.app.example.com TXT "heritage=external-dns,external-dns/owner=..."

This prevents conflicts when multiple external-dns instances manage the same domain.

Owner ID¶

Configure unique owner per cluster:

txtOwnerId: cluster-production

TXT Prefix¶

Configure TXT record prefix:

txtPrefix: "_externaldns."

UniFi-Specific Behavior¶

Record Creation¶

Each target creates a separate DNS record in UniFi:

# This annotation:
external-dns.alpha.kubernetes.io/target: "10.0.0.1,10.0.0.2"

# Creates two records in UniFi:
# app.example.com A 10.0.0.1
# app.example.com A 10.0.0.2

Record Updates¶

Updates are performed as delete + create operations.

Record Deletion¶

Records are deleted when:

Kubernetes resource is deleted (with policy: sync)
Annotation is removed
Service loses its external IP

Best Practices¶

Use unique owner IDs per cluster to prevent conflicts
Avoid wildcard CNAME - use individual records
Set appropriate TTL for your use case
Use domain filters to limit scope
Test in staging before production deployment