- 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.
If a Node name in the cluster is already taken and this Node is Ready,
prevent TLS bootsrap on "kubeadm join" and exit early.
This change requires that a new ClusterRole is granted to the
"system:bootstrappers:kubeadm:default-node-token" group to be
able get Nodes in the cluster. The same group already has access
to obtain objects such as the KubeletConfiguration and kubeadm's
ClusterConfiguration.
The motivation of this change is to prevent undefined behavior
and the potential control-plane breakdown if such a cluster
is racing to have two nodes with the same name for long periods
of time.
The following values are validated in the following precedence
from lower to higher:
- actual hostname
- NodeRegistration.Name (or "--node-name") from JoinConfiguration
- "--hostname-override" passed via kubeletExtraArgs
If the user decides to not let kubeadm know about a custom node name
and to instead override the hostname from a kubelet systemd unit file,
kubeadm will not be able to detect the problem.
- Extend the exponential backoff for add/remove/... retry to
11 steps ~=106 seconds. From experiments for 3 and more members
the race can take more that ~=26 seconds.
- Increase the dialTimeout for client creation to 40 seconds.
20 seconds seems racy for 3 and more members.
For the etcd client, amend AddMember() to handle a very
rare bug when multiple members can end up with the same
name. Match the member peer address and assign it the name of
the member we are adding. For the rest of the members with missing
names use their member IDs as name. The etcd node is not disrupted
by the unknown names.
The important aspects are:
- The number of members of the initial cluster must match
the members in the cluster.
- The member we are current adding is present in the initial cluster.
As part of #68522, Switching off the cAdvisor v1 Json API that we expose
directly. These include /stats/, /stats/container, /stats/{podName}/{containerName},
and /stats/{namespace}/{podName}/{uid}/{containerName}
The CoreDNS GA feature-gate in kubeadm was deprecated since 1.13.
The k8s policy is to remove the gate 2 releases after it transitions
to GA:
https://kubernetes.io/docs/reference/using-api/deprecation-policy/#deprecation
We kept it around for longer to prevent existing setups from breaking
as it caused minimal maintenance overhead.
This creates a new EndpointSliceProxying feature gate to cover EndpointSlice
consumption (kube-proxy) and allow the existing EndpointSlice feature gate to
focus on EndpointSlice production only. Along with that addition, this enables
the EndpointSlice feature gate by default, now only affecting the controller.
The rationale here is that it's really difficult to guarantee all EndpointSlices
are created in a cluster upgrade process before kube-proxy attempts to consume
them. Although masters are generally upgraded before nodes, and in most cases,
the controller would have enough time to create EndpointSlices before a new node
with kube-proxy spun up, there are plenty of edge cases where that might not be
the case. The primary limitation on EndpointSlice creation is the API rate limit
of 20QPS. In clusters with a lot of endpoints and/or with a lot of other API
requests, it could be difficult to create all the EndpointSlices before a new
node with kube-proxy targeting EndpointSlices spun up.
Separating this into 2 feature gates allows for a more gradual rollout with the
EndpointSlice controller being enabled by default in 1.18, and EndpointSlices
for kube-proxy being enabled by default in the next release.
