* 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))

- 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))

 
## Changes by Kind

### Bug or Regression

- CVE-2020-8557 (Medium): Node-local denial of service via container /etc/hosts file. See https://github.com/kubernetes/kubernetes/issues/93032 for more details. ([#92916](https://github.com/kubernetes/kubernetes/pull/92916), [@joelsmith](https://github.com/joelsmith)) [SIG Node]

### Bug or Regression

- CVE-2020-8557 (Medium): Node-local denial of service via container /etc/hosts file. See https://github.com/kubernetes/kubernetes/issues/93032 for more details. ([#92916](https://github.com/kubernetes/kubernetes/pull/92916), [@joelsmith](https://github.com/joelsmith)) [SIG Node]

- Mitigate CVE-2020-8555 for kube-up using GCE by preventing local loopback folume hosts. ([#97934](https://github.com/kubernetes/kubernetes/pull/97934), [@mattcary](https://github.com/mattcary)) [SIG Cloud Provider and Storage]

- Kubeadm: switch the preflight check (called 'Swap') that verifies if swap is enabled on Linux hosts to report a warning instead of an error. This is related to the graduation of the NodeSwap feature gate in the kubelet to Beta and being enabled by default in 1.23 - allows swap support on Linux hosts. In the next release of kubeadm (1.24) the preflight check will be removed, thus we recommend that you stop using it - e.g. via `--ignore-preflight-errors`...

- 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

* Refactor addons into multiple packages ([#50214](https://github.com/kubernetes/kubernetes/pull/50214), [@andrewrynhard](https://github.com/andrewrynhard))
* Kubelet now manages `/etc/hosts` file for both hostNetwork Pods and non-hostNetwork Pods. ([#49140](https://github.com/kubernetes/kubernetes/pull/49140), [@rickypai](https://github.com/rickypai))

- Service Controller: will now update load balancer hosts after node's `ProviderID` is
  updated. ([#120492](https://github.com/kubernetes/kubernetes/pull/120492), [@cezarygerard](https://github.com/cezarygerard))

  2. Fixed a bug where the pod is unexpectedly running when the `image` volume source type is used and mounted to `/etc/hosts` in the container. ([#126806](https://github.com/kubernetes/kubernetes/pull/126806), [@carlory](https://github.com/carlory)) [SIG Node and Storage]