postBuild.substituteFrom can only read a ConfigMap in its own namespace.
dataplane-template-defaults existed only in flux-system, so every gateway
Kustomization had to live in flux-system to reach it — a namespace the
feature teams have no access to. Their own gateway configuration ended up
outside their reach as a side effect of a substitution rule, not as a
governance decision.
Add a namespace-less copy of the ConfigMap under
kong-platform/domain-defaults, plus one Kustomization per domain in
flux/domain-defaults.yaml differing only by targetNamespace. One source
file, one edit when a default changes, six copies that follow.
Platform-owned deliberately: these are the defaults a team inherits, not
ones it sets, so they stay in flux-system while everything a team does own
moves out of it.
This is the precondition, not the move itself. The flux-system copy stays
until the gateway Kustomizations relocate, and they cannot be patched into
a new namespace — that is a delete and recreate, with a window where the
gateway is unreconciled.
It also retires a workaround: platform-llm inlined OTEL_TRACES_ENDPOINT
because its Kustomization had to sit in the llm namespace, holding real
credentials it must not put in flux-system, and so could not read this
ConfigMap. With the ConfigMap in llm, that inlining can go.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Stéphane Tailland