// serving certificate of the backend it is connecting to.  This will make the HTTPS connection between the apiserver
  // and the backend insecure. This means the apiserver cannot verify the log data it is receiving came from the real
  // kubelet.  If the kubelet is configured to verify the apiserver's TLS credentials, it does not mean the

- The default delegating authorization options now allow unauthenticated access to healthz, readyz, and livez.  A system:masters user connecting to an authz delegator will not perform an authz check. ([#98325](https://github.com/kubernetes/kubernetes/pull/98325), [@deads2k](https://github.com/deads2k)) [SIG API Machinery, Auth, Cloud Provider and Scheduling]

* Add conntrack as a dependency of kubelet and kubeadm when building rpms and debs. Both require conntrack to handle cleanup of connections. ([#71540](https://github.com/kubernetes/kubernetes/pull/71540), [@mauilion](https://github.com/mauilion))
* UDP connections now support graceful termination in IPVS mode ([#71515](https://github.com/kubernetes/kubernetes/pull/71515), [@lbernail](https://github.com/lbernail))

## Changelog since v1.13.5

### Other notable changes

* Connections from Pods to Services with 0 endpoints will now ICMP reject immediately, rather than blackhole and timeout. ([#72534](https://github.com/kubernetes/kubernetes/pull/72534), [@thockin](https://github.com/thockin))

## Changelog since v1.12.7

### Other notable changes

* Connections from Pods to Services with 0 endpoints will now ICMP reject immediately, rather than blackhole and timeout. ([#72534](https://github.com/kubernetes/kubernetes/pull/72534), [@thockin](https://github.com/thockin))

- Packets considered INVALID by conntrack are now dropped. In particular, this fixes
a problem where spurious retransmits in a long-running TCP connection to a service
IP could result in the connection being closed with the error "Connection reset by
peer" ([#74840](https://github.com/kubernetes/kubernetes/pull/74840), [@anfernee](https://github.com/anfernee))

- Don't use a custom dialer for the kubelet if is not rotating certificates, so we can reuse TCP connections and have only one between the apiserver and the kubelet.

* kubeadm: avoid double deletion of the upgrade prepull DaemonSet ([#80798](https://github.com/kubernetes/kubernetes/pull/80798), [@xlgao-zju](https://github.com/xlgao-zju))
* Fixes problems with connecting to services on localhost on some systems; in particular, DNS queries to systemd-resolved on Ubuntu. ([#80591](https://github.com/kubernetes/kubernetes/pull/80591), [@danwinship](https://github.com/danwinship))

- HTTP/2 connection health check is enabled by default in all Kubernetes clients to fix persistently broken connections (https://github.com/kubernetes/client-go/issues/374). If needed, users can tune the feature via the HTTP2_READ_IDLE_TIMEOUT_SECONDS and HTTP2_PING_TIMEOUT_SECONDS environment variables. The feature...

[@kawych](https://github.com/kawych))

* On cluster provision or upgrade, kubeadm now generates certs and secures all connections to the etcd static-pod with mTLS. This includes the etcd serving cert, the etcd peer cert, and the apiserver etcd client cert. Flags and hostMounts are added to the etcd and apiserver static-pods to load these certs. For connections to etcd, https is now used in favor of http. ([#57415](https://github.com/kubernetes/kubernetes/pull/57415), [@stealthybox](htt...