fix: route Hostname/ServiceEntry backendRefs to the requested port on multi-port hosts#14212
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ymesika merged 4 commits intoJun 9, 2026
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… multi-port hosts Signed-off-by: Yossi Mesika <[email protected]>
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Pull request overview
Fixes incorrect backend resolution when an HTTPRoute backendRef of kind: Hostname or kind: ServiceEntry specifies a port against a multi-port ServiceEntry host. The root cause was backendKey key-string serialization dropping the port, collapsing all ports into the same KRT index bucket and allowing the wrong cluster to be chosen at runtime.
Changes:
- Add a
backendKey.String()implementation that includes the port to ensure per-port index bucketing. - Add new serviceentry/destination-rule golden test coverage for a multi-port
ServiceEntryreferenced viaHostnamebackendRef with an explicit port. - Add/record expected output demonstrating routing to the correct
..._80cluster (instead of incorrectly selecting..._443).
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| pkg/krtcollections/policy.go | Adds backendKey.String() that includes port to prevent index key collisions across ports. |
| pkg/kgateway/setup/testdata/serviceentry/dr/se-hostname-ref-multiport.yaml | New test input: multi-port ServiceEntry with HTTPRoute referencing host via Hostname backendRef on port 80. |
| pkg/kgateway/setup/testdata/serviceentry/dr/se-hostname-ref-multiport-out.yaml | New golden output verifying the route cluster resolves to the ..._80 ServiceEntry cluster. |
davidjumani
approved these changes
Jun 9, 2026
davidjumani
enabled auto-merge
June 9, 2026 13:55
puertomontt
reviewed
Jun 9, 2026
Co-authored-by: Omar Hammami <[email protected]> Signed-off-by: Yossi Mesika <[email protected]>
Signed-off-by: Yossi Mesika <[email protected]>
puertomontt
approved these changes
Jun 9, 2026
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Description
An HTTPRoute
backendRefofkind: Hostnameorkind: ServiceEntrywith an explicitportcould route to the wrong port's cluster when the target ServiceEntry defines multiple ports for the same host.Example: a ServiceEntry exposing both
:80and:443onse.example.com, with an HTTPRoute backendRef ofport: 80, routes to the..._443cluster instead of..._80. The route showsAccepted/ResolvedRefs, so it only fails at runtime as wrong upstream routing (e.g.400 Client sent an HTTP request to an HTTPS server, or503against an HTTP-only backend).Root cause
ServiceEntry backends are aliased into the
BackendIndexkeyed bybackendKey, which embedsir.ObjectSourceplus aport. The KRT index serializes keys viafmt.Stringer, butbackendKeyhad noString()of its own — so the embeddedir.ObjectSource.String()was promoted, and that only encodesgroup/kind/namespace/name, dropping the port.Every port of a multi-port host therefore hashed to the same bucket. A lookup for
:80returned all ports' backends, and theResourceName()tiebreak picked:443(...:443_...sorts before...:80_...since"4" < "8") regardless of the requested port.The Fix
Give
backendKeyaString()that includes the port, so each (source, port) gets its own bucket.Applies to both
kind: Hostnameandkind: ServiceEntrybackendRefs.Change Type
/kind fix
Changelog
Additional Notes