The conformance test for ServiceAccountIssuerDiscovery is currently
configured with --in-cluster-discovery, which only supports token
validation against in-cluster endpoints. Many cloud providers provide
their own, external endpoints for OIDC discovery, and because the iss
claim in tokens will point to these endpoints, but the client in this
test only trusts the Cluster CA, it will fail to connect to the external
discovery endpoints when validating the token.
To ensure that the conformance test at least supports scenario where
both the discovery doc endpoint and JWKS endpoint are cluster-local and
the scenario where both endpoints are cluster-external, this PR has the
test try both and requires at least one to pass.
Caveat: The test still won't support a configuration where one
endpoint is cluster-local and the other is external. We don't yet have
evidence that this is a configuration that is used in practice, so this
initial hotfix will at least fix the conformance test for the "both
external" configuration we know providers already use. Note that if one
endpoint is cluster-local, and the other is cluster-external, tokens can
still only be validated in-cluster, because both endpoints must be
accessible to Relying Parties that validate tokens.
0b3b99c096