Provide options to create a RAID on ROOT disk

[rsevilla87]

The option of creating software based RAID on ROOT disk should be available in the installer.
I'm open to suggestions about modification of the code :).

[bgilbert]

We explicitly don't want to support this sort of thing in the installer, since storage configuration should be possible on every platform and the installer doesn't run in the cloud. Instead, storage configuration should be performed by Ignition, which runs on every platform. Ignition already supports creating RAID volumes for data disks, but we don't currently support root on RAID; see coreos/fedora-coreos-tracker#94.

[cgwalters]

Restating in a different way bgilbert's reply: This is starting to create a kind of distinct mini-language/config format for partitioning/storage (like Kickstart) - from my ("old school RHT") view, a major benefit of Ignition is unifying Kickstart and cloud-init. Then for RHCOS, we support "day 2" management of Ignition via MachineConfig.

One could imagine in the future even a model where the MCO supports re-configuring the partitioning for extant nodes (maybe via re-provisioning at an IaaS level, maybe in-place if we have free raw partitions space w/LVM), etc. We can't do that type of stuff if the state of the system is invisible to it (i.e. it's not encoded in Ignition).

[xguitian]

@cgwalters but ignoring that is not yet supperted on Fedora CoreOS, do you really envision a to move root to a RAID after install?

[cgwalters]

@cgwalters but ignoring that is not yet supperted on Fedora CoreOS, do you really envision a to move root to a RAID after install?

Yes, see coreos/ignition-dracut#107

[bgilbert]

Thanks for the PR. The installer isn't the right place for this sort of functionality, and we have no plans to add it here. I'll go ahead and close.