This reverts commit 8597b343fa.
I wrote in the Kubernetes documentation:
In practice this means you need at least Linux 6.3, as tmpfs started
supporting idmap mounts in that version. This is usually needed as
several Kubernetes features use tmpfs (the service account token that is
mounted by default uses a tmpfs, Secrets use a tmpfs, etc.)
The check is wrong for several reasons:
* Pods can use userns before 6.3, they will just need to be
careful to not use a tmpfs (like a serviceaccount). MOST users
will probably need 6.3, but it is possible to use earlier kernel
versions. 5.19 probably works fine and with improvements in
the runtime 5.12 can probably be supported too.
* Several distros backport changes and the recommended way is
usually to try the syscall instead of testing kernel versions.
I expect support for simple fs like tmpfs will be backported
in several distros, but with this check it can generate confusion.
* Today a clear error is shown when the pod is created, so it's
unlikely a user will not understand why it fails.
* Returning an error if utilkernel fails to understand what
kernel version is running is also too strict (as we are
logging a warning even if it is not the expected version)
* We are switching to enabled by default, which will log a
warning on every user that runs on an older than 6.3 kernel,
adding noise to the logs.
For there reasons, let's just remove the hardcoded kernel version check.
Signed-off-by: Rodrigo Campos <rodrigoca@microsoft.com>
