[RFE] EROFS support

[ruuda]

Current situation

modprobe erofs fails on Flatcar stable 4152.2.1 because the EROFS kernel module is not included.

Impact

I can’t use EROFS to package applications for use with systemd’s RootImage=, so I continue to use Squashfs for this. I’d be interested in switching Miniserver to EROFS, but Squashfs works fine.

Squashfs was designed in the age of live cds, but we are now in the age where applications are being distributed as filesystem images. EROFS seems more aligned for this use case, and in general seems to align well with Flatcar’s use case.

There are some downsides:

• Adding a kernel module increases the size of the root filesystem, which may not be worth the overhead.
• Adding a kernel module increases attack surface.

I’m opening this issue partially to gauge interest, to see if interest outweighs these downsides.

Ideal future situation

modprobe erofs succeeds.

[tormath1]

+1 - I know that FCOS is using a lot EROFS (for systemd sysexts too), this could help to merge the sysext effort with FCOS folks. I can have a look to enable this module and check for how much it increases the kernel size.

[tormath1]

Thanks @ruuda for opening this issue. erofs support has been merged and should be available in the next Alpha release (beginning of March). I'll get back to you on this issue when it will be released to see if works for you as expected.

[ruuda]

I tested 4284.0.0 alpha and I can confirm that EROFS works on there. Thanks a lot!

[tormath1]

Thanks for testing and for the feature request! Let's close this then. It should be already available in the next Beta (in April).