When doing the very first upgrade from a cluster that contains the
source of truth in the ClusterStatus struct, the new kubeadm logic
will try to retrieve this information from annotations.
This changeset adds to both etcd and apiserver endpoint retrieval the
special case in which they won't retry if we are in such cases. The
logic will retry if we find any unknown error, but will not retry in
the following cases:
- etcd annotations do not contain etcd endpoints, but the overall list
of etcd pods is greater than 0. This means that we listed at least
one etcd pod, but they are missing the annotation.
- API server annotation is not found on the api server pod for a given
node name, but no errors aside from that one were found. This means
that the API server pod is present, but is missing the annotation.
In both cases there is no point in retrying, and so, this speeds up the
upgrade path when coming from a previous existing cluster.
While `ClusterStatus` will be maintained and uploaded, it won't be
used by the internal `kubeadm` logic in order to determine the etcd
endpoints anymore.
The only exception is during the first upgrade cycle (`kubeadm upgrade
apply`, `kubeadm upgrade node`), in which we will fallback to the
ClusterStatus to let the upgrade path add the required annotations to
the newly created static pods.
While kubeadm does not support CA rotation,
the users might still attempt to perform this manually.
For kubeconfig files, updating to a new CA is not reflected
and users need to embed new CA PEM manually.
On kubeconfig cert renewal, always keep the embedded CA
in sync with the one on disk.
Includes a couple of typo fixes.
- Add handlers for service account issuer metadata.
- Add option to manually override JWKS URI.
- Add unit and integration tests.
- Add a separate ServiceAccountIssuerDiscovery feature gate.
Additional notes:
- If not explicitly overridden, the JWKS URI will be based on
the API server's external address and port.
- The metadata server is configured with the validating key set rather
than the signing key set. This allows for key rotation because tokens
can still be validated by the keys exposed in the JWKs URL, even if the
signing key has been rotated (note this may still be a short window if
tokens have short lifetimes).
- The trust model of OIDC discovery requires that the relying party
fetch the issuer metadata via HTTPS; the trust of the issuer metadata
comes from the server presenting a TLS certificate with a trust chain
back to the from the relying party's root(s) of trust. For tests, we use
a local issuer (https://kubernetes.default.svc) for the certificate
so that workloads within the cluster can authenticate it when fetching
OIDC metadata. An API server cannot validly claim https://kubernetes.io,
but within the cluster, it is the authority for kubernetes.default.svc,
according to the in-cluster config.
Co-authored-by: Michael Taufen <mtaufen@google.com>
It turns out that the dual-stack feature enabled doesn't mean that
the cluster MUST be dual-stack, it only indicates that it MAY be
dual-stack but CAN be single-stack.
We should relax the validation to allow single-stack clusters
with dual-stack enabled.
