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fix(external-dns): restrict Cloudflare record scope #2743

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devantler wants to merge 4 commits into from
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fix(external-dns): restrict Cloudflare record scope #2743

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fix(external-dns): restrict Cloudflare record scope
devantler Jul 18, 2026
23a725a
Merge branch 'main' into codex/fix-arbitrary-cloudflare-zone-record-v…
devantler Jul 19, 2026
0f4b6ed
Merge branch 'main' into codex/fix-arbitrary-cloudflare-zone-record-v…
devantler Aug 14, 2026
56feba6
Merge branch 'main' into codex/fix-arbitrary-cloudflare-zone-record-v…
devantler Aug 15, 2026
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2 changes: 2 additions & 0 deletions k8s/clusters/prod/bootstrap/config-map.yaml
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Expand Up @@ -7,6 +7,8 @@ metadata:
data:
cluster_name: prod
domain: platform.devantler.tech
# Escaped form of domain for external-dns --regex-domain-filter.
external_dns_domain_regex: 'platform\.devantler\.tech'
github_app_client_id: Iv23limfvbk93bAXZI6b
issuer_group: cert-manager.io
issuer_kind: ClusterIssuer
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3 changes: 3 additions & 0 deletions k8s/providers/hetzner/infrastructure/external-dns/helm-release.yaml
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Expand Up @@ -36,6 +36,9 @@ spec:
- "${cloudflare_zone}"
extraArgs:
- --exclude-target-net=10.0.0.0/8
# Restrict Gateway HTTPRoute-derived records to this cluster's delegated
# DNS subtree while domainFilters still selects the Cloudflare zone apex.
- --regex-domain-filter=^([a-z0-9]([-a-z0-9]*[a-z0-9])?\.)*${external_dns_domain_regex}$

@devantler devantler Aug 9, 2026

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[P1] Keep the Cloudflare apex discoverable

At the pinned ExternalDNS v0.21.0, setting --regex-domain-filter switches the shared domain filter to regex mode, so the domainFilters value above is ignored. The Cloudflare provider applies that same filter to zone.Name before it reads or applies records. This pattern accepts platform.devantler.tech and its descendants but rejects the actual Cloudflare zone apex devantler.tech, leaving Zones() empty and preventing reconciliation for every managed record. Configure an exact zone-ID filter so provider discovery bypasses the record-name regex (without publishing the identifier), or otherwise prove an equivalent boundary; add a rendered/behavioral guard showing the apex zone is discovered while sibling subdomains outside the delegated subtree are rejected.

- --cloudflare-proxied
env:
- name: CF_API_TOKEN
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