Allow leaving additional disks unformatted

[afbjorklund]

Default to a simple string with name, just like before.

additionalDisks:
- "disk"

But also allow skipping the partitioning and formatting.

additionalDisks:
- name: "disk"
  format: true
  fsType: "ext4"

---

Example 1)

Like when running something like ceph, which uses LVM.

It requires the entire disk device to be "raw", unformatted:

additionalDisks:
- name: "disk"
  format: false

https://docs.ceph.com/en/latest/cephadm/install/

A storage device is considered available if all of the following conditions are met:

• The device must have no partitions.
• The device must not have any LVM state.
• The device must not be mounted.
• The device must not contain a file system.
• The device must not contain a Ceph BlueStore OSD.
• The device must be larger than 5 GB.

Example 2)

Also allow using something else than "ext4", like "xfs".

Or for adding custom arguments, such as with glusterfs:

additionalDisks:
- name: "disk"
  format: true
  fsType: "xfs"
  fsArgs: ["-i","size=512"]

https://docs.gluster.org/en/latest/Quick-Start-Guide/Quickstart/

The inode size is set to 512 bytes to accommodate for the extended attributes used by GlusterFS.

---

Closes #1393

[AkihiroSuda]

Is this still a draft?

[afbjorklund]

I think I put it in a draft, mostly in order to not interfere with the release at that time. Also haven't tested it since.

Will rebase

[AkihiroSuda]

Thanks