fix(pihole): create record for all targets

[vkolobara]

What does it do ?

• create multiple targets for A and AAAA records for the pihole provider

Motivation

#5423

Since a month already passed from the original PR without any updates, I created this PR with some improvements.
It's also fine by me if the original PR gets merged after appropriate changes, I don't want to take any credits or anything, just want to get this fix in place :).

Open questions

Should we do anything if any of the individual requests fail, e.g.

1. I want to create a DNS entry with multiple targets: example.com, [192.168.1.2, 192.168.1.3]
2. The first entry gets created: example.com 192.168.1.2
3. The second entry fails for some reason

The same would probably happen with updates.

As it currently stands (if I read it correctly), updates and failures wouldn't get noticed ever:

external-dns/provider/pihole/pihole.go

Lines 111 to 120 in 2d898cd

	for _, ep := range changes.UpdateOld {
	// Check if this existing entry has an exact match for an updated entry and skip it if so.
	key := piholeEntryKey{ep.DNSName, ep.RecordType}
	if newRecord := updateNew[key]; newRecord != nil {
	// PiHole only has a single target; no need to compare other fields.
	if newRecord.Targets[0] == ep.Targets[0] {
	delete(updateNew, key)
	continue
	}
	}

Should we also update the old pihole client to work with multiple targets or create different logic in the Pihole Provider depending on the pihole version?

More

• Yes, this PR title follows Conventional Commits
• Yes, I added unit tests
• Yes, I updated end user documentation accordingly

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: vkolobara (9e49d04, 76b8bfd, cd570cd, 2fb9a35, 97f3088, f460518, 3c1304d, 1f0502c, 055abc2)

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @vkolobara. Thanks for your PR.

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[ivankatliarchuk]

/ok-to-test

[ivankatliarchuk]

Is it actually solving the issue? By any chance could you share k8 manifests, arguments and results of a smoke test with and without a fix?

[vkolobara]

I needed to do one more commit and change listRecords (and fix the appropriate tests), but this is what I got locally - everyting works correctly:

In-cluster external-dns deployment (only relevant parts)

spec:
  selector:
    matchLabels:
      app: external-dns
  strategy:
    type: Recreate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: external-dns
    spec:
      containers:
      - args:
        - --source=service
        - --source=ingress
        - --registry=noop
        - --policy=upsert-only
        - --provider=pihole
        - --pihole-api-version=6
        - --pihole-server=http://pihole.pihole
        envFrom:
        - secretRef:
            name: pihole-password
        image: registry.k8s.io/external-dns/external-dns:v0.18.0

Pihole logs with cluster external-dns deployment (errors):

│ pihole 2025-06-30 14:54:53.576 UTC [49/T252] WARNING: API: Invalid value (key: bad_request, hint: dns.hosts[8]: neither a valid IPv4 nor IPv6 address ("192.168.0.14;192.168.0.201"))

Local run of external-dns with these changes:

 ~/p/external-dns (fix/pihole-v6-multiple-targets)> go run main.go --provider=pihole --registry=noop --source=ingress --pihole-api-version=6 --pihole-server=http://localhost:8080 --log-level=info --pihole-password password --once
INFO[0000] Instantiating new Kubernetes client
INFO[0000] Using kubeConfig
INFO[0000] Created Kubernetes client https://192.168.0.14:6443
INFO[0000] PUT example1.com IN A -> 192.168.0.14
INFO[0000] PUT example1.com IN A -> 192.168.0.201
INFO[0000] PUT example2.com IN A -> 192.168.0.14
INFO[0000] PUT example2.com IN A -> 192.168.0.201
INFO[0000] PUT example3.com IN A -> 192.168.0.14
INFO[0000] PUT example3.com IN A -> 192.168.0.201
INFO[0000] PUT example4.com IN A -> 192.168.0.14
INFO[0000] PUT example4.com IN A -> 192.168.0.201
INFO[0000] PUT example5.com IN A -> 192.168.0.14
INFO[0000] PUT example5.com IN A -> 192.168.0.201
INFO[0000] PUT example6.com IN A -> 192.168.0.14
INFO[0000] PUT example6.com IN A -> 192.168.0.201
INFO[0000] PUT example7.com IN A -> 192.168.0.14
INFO[0001] PUT example7.com IN A -> 192.168.0.201
INFO[0001] PUT example8.com IN A -> 192.168.0.14
INFO[0001] PUT example8.com IN A -> 192.168.0.201

Example run again
[0000] All records are already up to date

Deleted example1.com 192.168.0.14, example2.com 192.168.0.201, example3.com 192.168.0.14 and run it again:

INFO[0000] DELETE example1.com IN A -> 192.168.0.201
INFO[0000] DELETE example2.com IN A -> 192.168.0.14
INFO[0000] DELETE example3.com IN A -> 192.168.0.201
INFO[0000] PUT example1.com IN A -> 192.168.0.14
INFO[0000] PUT example1.com IN A -> 192.168.0.201
INFO[0000] PUT example2.com IN A -> 192.168.0.14
INFO[0000] PUT example2.com IN A -> 192.168.0.201
INFO[0000] PUT example3.com IN A -> 192.168.0.14
INFO[0000] PUT example3.com IN A -> 192.168.0.201

[ivankatliarchuk]

Should be covered with tests

[ivankatliarchuk]

missing test coverage

[ivankatliarchuk]

not covered with tests

[ivankatliarchuk]

Hi @tJouve,

Any chance for a final review if you have time? Thanks!

[tJouve]

Hello @ivankatliarchuk ,

I had a look, seems good.

Thanks for the fix @vkolobara

[ivankatliarchuk]

/lgtm

[mloiseleur]

/approve

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This pull-request has been approved by: mloiseleur

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