Merge pull request containers#10525 from rhatdan/docs1

[CI:DOCS] Add documentation on ignore_chown_errors

docs/source/markdown/podman.1.md

@@ -336,9 +336,11 @@ Images are pulled under `XDG_DATA_HOME` when specified, otherwise in the home di
 
 Currently the slirp4netns package is required to be installed to create a network device, otherwise rootless containers need to run in the network namespace of the host.
 
+In certain environments like HPC (High Performance Computing), users cannot take advantage of the additional UIDs and GIDs from the /etc/subuid and /etc/subgid systems.  However, in this environment, rootless Podman can operate with a single UID.  To make this work, set the `ignore_chown_errors` option in the /etc/containers/storage.conf or in ~/.config/containers/storage.conf files. This option tells Podman when pulling an image to ignore chown errors when attempting to change a file in a container image to match the non-root UID in the image. This means all files get saved as the user's UID. Note this could cause issues when running the container.
+
 ### **NOTE:** Unsupported file systems in rootless mode
 
-The Overlay file system (OverlayFS) is not supported in rootless mode.  The fuse-overlayfs package is a tool that provides the functionality of OverlayFS in user namespace that allows mounting file systems in rootless environments.  It is recommended to install the fuse-overlayfs package.  In rootless mode Podman will automatically use the fuse-overlafs program as the mount_program if installed, as long as the $HOME/.config/containers/storage.conf file was not previously created.  If storage.conf exists in the homedir, add `mount_program = "/usr/bin/fuse-overlayfs"` under `[storage.options.overlay]` to enable this feature.
+The Overlay file system (OverlayFS) is not supported with kernels prior to 5.12.9 in rootless mode.  The fuse-overlayfs package is a tool that provides the functionality of OverlayFS in user namespace that allows mounting file systems in rootless environments.  It is recommended to install the fuse-overlayfs package.  In rootless mode, Podman will automatically use the fuse-overlayfs program as the mount_program if installed, as long as the $HOME/.config/containers/storage.conf file was not previously created.  If storage.conf exists in the homedir, add `mount_program = "/usr/bin/fuse-overlayfs"` under `[storage.options.overlay]` to enable this feature.
 
 The Network File System (NFS) and other distributed file systems (for example: Lustre, Spectrum Scale, the General Parallel File System (GPFS)) are not supported when running in rootless mode as these file systems do not understand user namespace.  However, rootless Podman can make use of an NFS Homedir by modifying the `$HOME/.config/containers/storage.conf` to have the `graphroot` option point to a directory stored on local (Non NFS) storage.