docs: update deprecation status for "overlay2.override_kernel_check"

Commit moby/moby@955c1f8
(v17.12.0) replaced detection of support for multiple lowerdirs (as required by
overlay2) to not depend on the kernel version. The `overlay2.override_kernel_check`
was still used to print a warning that older kernel versions may not have full
support.

After this, moby/moby@e226aea
(v20.10, but backported to v19.03.7) removed uses of the option altogether.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

docs/deprecated.md

@@ -69,6 +69,7 @@ The table below provides an overview of the current status of deprecated feature
 | Removed    | [`docker engine` subcommands](#docker-engine-subcommands)                                                                          | v19.03     | v20.10 |
 | Removed    | [Top-level `docker deploy` subcommand (experimental)](#top-level-docker-deploy-subcommand-experimental)                            | v19.03     | v20.10 |
 | Removed    | [`docker stack deploy` using "dab" files (experimental)](#docker-stack-deploy-using-dab-files-experimental)                        | v19.03     | v20.10 |
+| Disabled   | [Support for the `overlay2.override_kernel_check` storage option](#support-for-the-overlay2override_kernel_check-storage-option)   | v19.03     | -      |
 | Disabled   | [AuFS storage driver](#aufs-storage-driver)                                                                                        | v19.03     | -      |
 | Disabled   | [Legacy "overlay" storage driver](#legacy-overlay-storage-driver)                                                                  | v18.09     | -      |
 | Disabled   | [Device mapper storage driver](#device-mapper-storage-driver)                                                                      | v18.09     | -      |
@@ -464,6 +465,19 @@ format, support for the DAB file format and the top-level docker deploy command
 (hidden by default in 19.03), will be removed, in favour of `docker stack deploy`
 using compose files.
 
+### Support for the `overlay2.override_kernel_check` storage option
+
+**Deprecated in Release: v19.03**
+**Disabled in Release: v19.03**
+
+This daemon configuration option disabled the Linux kernel version check used
+to detect if the kernel supported OverlayFS with multiple lower dirs, which is
+required for the overlay2 storage driver. Starting with Docker v19.03.7, the
+detection was improved to no longer depend on the kernel _version_, so this
+option was no longer used.
+
+Docker v22.06 logs a warning in the daemon logs if this option is set, and
+users should remove this option from their daemon configuration.
 
 ### AuFS storage driver
 

docs/reference/commandline/dockerd.md

@@ -818,20 +818,11 @@ $ sudo dockerd -s btrfs --storage-opt btrfs.min_space=10G
 
 #### Overlay2 options
 
-##### `overlay2.override_kernel_check`
-
-Overrides the Linux kernel version check allowing overlay2. Support for
-specifying multiple lower directories needed by overlay2 was added to the
-Linux kernel in 4.0.0. However, some older kernel versions may be patched
-to add multiple lower directory support for OverlayFS. This option should
-only be used after verifying this support exists in the kernel. Applying
-this option on a kernel without this support will cause failures on mount.
-
 ##### `overlay2.size`
 
 Sets the default max size of the container. It is supported only when the
 backing fs is `xfs` and mounted with `pquota` mount option. Under these
-conditions the user can pass any size less then the backing fs size.
+conditions the user can pass any size less than the backing fs size.
 
 ###### Example