- Ceph RBD volume plugin now does not use any keyring (`/etc/ceph/ceph.client.lvs01cinder.keyring`, `/etc/ceph/ceph.keyring`, `/etc/ceph/keyring`, `/etc/ceph/keyring.bin`) for authentication. Ceph user credentials must be provided in PersistentVolume objects and referred Secrets. ([#75588](https://github.com/kubernetes/kubernetes/pull/75588), [@smileusd...

or `/etc/sysconfig/kubelet`, depending on the system you're running on.
([#64780](https://github.com/kubernetes/kubernetes/pull/64780), [@luxas](https://github.com/luxas))

  * A new field hostAliases has been added to the pod spec to support [adding entries to a Pod's /etc/hosts file](https://kubernetes.io/docs/concepts/services-networking/add-entries-to-pod-etc-hosts-with-host-aliases/). ([#44641](https://github.com/kubernetes/kubernetes/pull/44641), [@rickypai](https://github.com/rickypai))

- Kubeadm: Removed support for mounting /etc/pki as an additional Linux system CA location
  in kube-apisever and kube-controller-manager pods. Instead, it shifted to supporting the
  mounting of /etc/pki/ca-trust and /etc/pki/tls/certs. The locations /etc/ca-certificate,
  /usr/share/ca-certificates, /usr/local/share/ca-certificates, and /etc/ssl/certs continued

- Kubeadm: fix panic in the command "kubeadm certs check-expiration" when "/etc/kubernetes/pki" exists but cannot be read. ([#124124](https://github.com/kubernetes/kubernetes/pull/124124), [@carlory](https://github.com/carlory)) [SIG Cluster Lifecycle]

* Fix a bug that fluentd doesn't inject container logs for CRI container runtimes (containerd, cri-o etc.) into elasticsearch on GCE. ([#61818](https://github.com/kubernetes/kubernetes/pull/61818), [@Random-Liu](https://github.com/Random-Liu))...

- The new test `[sig-network] DNS should now provide /etc/hosts entries for the cluster [LinuxOnly] [Conformance]` will validate the host entries set in the ``/etc/hosts`` file (pod's FQDN and hostname), which should be managed by Kubelet. ([#72729](https://github.com/kubernetes/kubernetes/pull/72729), [@bclau](https://github.com/bclau))

## WARNING: etcd backup strongly recommended

Before updating to 1.6, you are strongly recommended to back up your etcd data.
Please consult the installation procedure you are using (kargo, kops, kube-up,
kube-aws, kubeadm etc) for specific advice.

1.6 encourages etcd3, and switching from etcd2 to etcd3 involves a full
migration of data between different storage engines.  You must stop the API

- Images for cloud-controller-manager, kube-apiserver, kube-controller-manager, and kube-scheduler now contain a minimal /etc/nsswitch.conf and should respect /etc/hosts for lookups ([#69238](https://github.com/kubernetes/kubernetes/pull/69238), [@BenTheElder](https://github.com/BenTheElder))

### SIG Scheduling

- Kubeadm: fix panic in the command "kubeadm certs check-expiration" when "/etc/kubernetes/pki" exists but cannot be read. ([#124124](https://github.com/kubernetes/kubernetes/pull/124124), [@carlory](https://github.com/carlory)) [SIG Cluster Lifecycle]