maas sends duplicate device info in config / need to be multipath aware

[Scott Moser]

when looking at bug 1523779 i tried to reproduce and hit an error.
maas sends a config like below.

The issue is that it has told curtin to do two different things with the device that is 'serial: IBM_IPR-0_5EC29C0000000080'. That disk is a multipath disk. So when maas commissioned it saw the disk as 2 devices, and then tells curtin to use it as the root device once and also to format it and put an mbr filesystem on it.

Theres no sane way that curtin could determine which is the "right" thing to do. It should notice the situation and exit, but maas is still going to have to learn about multipath.

-- maas sent config --
storage:
  config:
  - {grub_device: true, id: sda, model: IPR-0 5EC29C00, name: sda, ptable: msdos, serial: IBM_IPR-0_5EC29C0000000080, type: disk, wipe: superblock}
  - {id: sdb, model: IPR-0 5EC29C00, name: sdb, serial: IBM_IPR-0_5EC29C0000000060, type: disk, wipe: superblock}
  - {id: sdc, model: IPR-0 5EC29C00, name: sdc, serial: IBM_IPR-0_5EC29C0000000040, type: disk, wipe: superblock}
  - {id: sdd, model: IPR-0 5EC29C00, name: sdd, serial: IBM_IPR-0_5EC29C0000000020, type: disk, wipe: superblock}
  - {id: sde, model: IPR-0 5EC29C00, name: sde, serial: IBM_IPR-0_5EC29C00000000C0, type: disk, wipe: superblock}
  - {id: sdf, model: IPR-0 5EC29C00, name: sdf, serial: IBM_IPR-0_5EC29C00000000A0, type: disk, wipe: superblock}
  - {id: sdh, model: IPR-0 5EC29C00, name: sdh, serial: IBM_IPR-0_5EC29C0000000080, type: disk, wipe: superblock}
  - {id: sdi, model: IPR-0 5EC29C00, name: sdi, serial: IBM_IPR-0_5EC29C0000000060, type: disk, wipe: superblock}
  - {id: sdj, model: IPR-0 5EC29C00, name: sdj, serial: IBM_IPR-0_5EC29C0000000040, type: disk, wipe: superblock}
  - {id: sdk, model: IPR-0 5EC29C00, name: sdk, serial: IBM_IPR-0_5EC29C0000000020, type: disk, wipe: superblock}
  - {id: sdl, model: IPR-0 5EC29C00, name: sdl, serial: IBM_IPR-0_5EC29C00000000C0, type: disk, wipe: superblock}
  - {id: sdm, model: IPR-0 5EC29C00, name: sdm, serial: IBM_IPR-0_5EC29C00000000A0, type: disk, wipe: superblock}
  - {device: sda, id: sda-part1, name: sda-part1, number: 1, offset: 4194304B, size: 283786608640B, type: partition, uuid: 6193de67-6b76-4cb6-bf6d-25518842d54b, wipe: superblock}
  - devices: [sda-part1]
    id: vgroot
    name: vgroot
    type: lvm_volgroup
    uuid: 93d1991a-9631-4051-81dd-c60d3267f23b
  - {id: vgroot-lvroot, name: lvroot, size: 283782414336B, type: lvm_partition, volgroup: vgroot}
  - {fstype: ext4, id: vgroot-lvroot_format, label: root, type: format, uuid: efdcbb0b-b9ca-455f-8cf9-1dbfc820717a, volume: vgroot-lvroot}
  - {device: vgroot-lvroot_format, id: vgroot-lvroot_mount, path: /, type: mount}
  version: 1

[Newell Jensen (newell-jensen)]

This still needs to be backported to MAAS 1.9 I believe.