Kubernetes was previously detecting that the image filesystem was split, even when that was not really the case ([#128344](https://github.com/kubernetes/kubernetes/pull/128344), [@kannon92](https://github.com/kannon92)) [SIG Node]
- Fixed an issue in the kubelet that showed when writeable layers and read-only layers were at different paths within the same mount.

* Fixes issue where subpath volume content was deleted during orphaned pod cleanup for Local volumes that are directories (and not mount points) on the root filesystem. ([#72291](https://github.com/kubernetes/kubernetes/pull/72291), [@msau42](https://github.com/msau42))

- kube-dns add-on:
  - All containers are now being executed under more restrictive privileges.
  - Most of the containers now run as non-root user and has the root filesystem set as read-only.
  - The remaining container running as root only has the minimum Linux capabilities it requires to run.

* Fixes issue where subpath volume content was deleted during orphaned pod cleanup for Local volumes that are directories (and not mount points) on the root filesystem. ([#72291](https://github.com/kubernetes/kubernetes/pull/72291), [@msau42](https://github.com/msau42))

  - [Changelog since v1.21.4](#changelog-since-v1214)
  - [Important Security Information](#important-security-information)
    - [CVE-2021-25741: Symlink Exchange Can Allow Host Filesystem Access](#cve-2021-25741-symlink-exchange-can-allow-host-filesystem-access)
  - [Changes by Kind](#changes-by-kind-8)
    - [Feature](#feature-6)
    - [Bug or Regression](#bug-or-regression-8)
    - [Other (Cleanup or Flake)](#other-cleanup-or-flake-1)

- Added container filesystem to the `ImageFsInfoResponse`. ([#120914](https://github.com/kubernetes/kubernetes/pull/120914), [@kannon92](https://github.com/kannon92))

public verifying keys. This was accomplished by enabling the beta `ExternalServiceAccountTokenSigner` feature gate and specifying the `--service-account-signing-endpoint` flag. The flag value could either be the path to a Unix domain socket on the filesystem, or be prefixed with @ to indicate a Unix domain socket in the abstract namespace. ([#131300](https://github.com/kubernetes/kubernetes/pull/131300), [@HarshalNeelkamal](https://github.com/HarshalNeelkamal)) [SIG API Machinery, Auth and Testing]...

  - [Changelog since v1.20.10](#changelog-since-v12010)
  - [Important Security Information](#important-security-information)
    - [CVE-2021-25741: Symlink Exchange Can Allow Host Filesystem Access](#cve-2021-25741-symlink-exchange-can-allow-host-filesystem-access)
  - [Changes by Kind](#changes-by-kind-4)
    - [Bug or Regression](#bug-or-regression-4)
    - [Other (Cleanup or Flake)](#other-cleanup-or-flake-1)
  - [Dependencies](#dependencies-4)

faster and more accurate than the old method of walking the filesystem tree. Note that it does not enforce limits, it only monitors consumption. To utilize this functionality, set the feature gate `LocalStorageCapacityIsolationFSQuotaMonitoring=true`. For ext4fs filesystems, create the filesystem with `mkfs.ext4 -O project <block_device>` and run `tune2fs -Q prjquota `block device`; XFS filesystems need no additional preparation. The filesystem must be mounted with option `project` in `/etc/fstab`. If...

* On GCI, NPD starts to monitor kubelet, docker, containerd crashlooping, read-only filesystem and corrupt docker overlay2 issues. ([#71522](https://github.com/kubernetes/kubernetes/pull/71522), [@wangzhen127](https://github.com/wangzhen127))