Research + implementation plan (no live change) on whether Cilium 1.20.1's
native Gateway API ExternalAuth filter (GEP-1494) can replace the un-wired
forward-auth CEC template and Crafty's oauth2-proxy sidecar.
Verdict: DEFER. The filter exists in 1.20.1 code (shipped 1.20.0, PR #45739) but
is EXPERIMENTAL-channel Gateway API; the cluster runs the standard-channel CRDs
(verified: HTTPRoute filters[].type enum lacks ExternalAuth), so it is not even
installable today. Also: fail-open bug (#47178, fixed#47265) in a brand-new
security filter, no 1.20 docs, and the ext_authz hop would hit the same
enforce_policy_on_l7lb hairpin re-evaluation just fixed for Keycloak (68690e5).
Plan is phased/reversible (pihole canary first) and keeps the working sidecar.
Resolves the DECISIONS-LOG open item on ext_authz workaround relevance under 1.20.1.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
jakman85andClaude Opus 4.8
b745bab26b