power8 scsii disks get blacklisted from multipath / curtin installed system doesnt boot

I attempted to install a curtin power 8 system with wily today today. It failed at initramfs not finding the multipath device.

I then forced installation without udev (by putting 'multipath: mode: disabled' into /etc/maas/preseeds/curtin_userdata).

Then, looking around to debug:

## wily system (no multipath used for boot, but package installed)
$ dpkg-query --show multipath-tools
multipath-tools 0.5.0-7ubuntu3

$ sudo multipath -ll
$ echo $?
0
$ sudo multipath -ll -v 3 > wily-multipath-ll-v3.txt
$ grep sda wily-multipath-ll-v3.txt
Aug 28 16:24:27 | sda: blacklisted, udev property missing

## vivid system (working multipath used for boot)
$ dpkg-query --show multipath-tools
multipath-tools 0.4.9-3ubuntu7.2

$ sudo multipath -ll
mpath2 (1IBM IPR-0 5EC2A90000000060) dm-1 IBM,IPR-0 5EC2A900
size=264G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=0 status=enabled
| `- 0:2:1:0 sdb 8:16 active faulty running
`-+- policy='round-robin 0' prio=10 status=active
  `- 1:2:1:0 sdh 8:112 active ready running
mpath1 (1IBM IPR-0 5EC2A90000000040) dm-2 IBM,IPR-0 5EC2A900
size=264G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=0 status=enabled
| `- 0:2:2:0 sdc 8:32 active faulty running
`-+- policy='round-robin 0' prio=10 status=active
  `- 1:2:2:0 sdi 8:128 active ready running
mpath0 (1IBM IPR-0 5EC2A90000000080) dm-4 IBM,IPR-0 5EC2A900
size=264G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=130 status=active
| `- 0:2:0:0 sda 8:0 active ready running
`-+- policy='round-robin 0' prio=0 status=enabled
  `- 1:2:0:0 sdg 8:96 active faulty running
mpath5 (1IBM IPR-0 5EC2A900000000A0) dm-0 IBM,IPR-0 5EC2A900
size=264G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=0 status=enabled
| `- 0:2:5:0 sdf 8:80 active faulty running
`-+- policy='round-robin 0' prio=10 status=active
  `- 1:2:5:0 sdl 8:176 active ready running
mpath4 (1IBM IPR-0 5EC2A900000000C0) dm-5 IBM,IPR-0 5EC2A900
size=264G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=0 status=enabled
| `- 0:2:4:0 sde 8:64 active faulty running
`-+- policy='round-robin 0' prio=10 status=active
  `- 1:2:4:0 sdk 8:160 active ready running
mpath3 (1IBM IPR-0 5EC2A90000000020) dm-3 IBM,IPR-0 5EC2A900
size=264G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=0 status=enabled
| `- 0:2:3:0 sdd 8:48 active faulty running
`-+- policy='round-robin 0' prio=10 status=active
  `- 1:2:3:0 sdj 8:144 active ready running

$ sudo multipath -ll -v 3 > vivid-multipath-ll-v3.txt
$ grep sda vivid-multipath-ll-v3.txt
Aug 28 16:21:34 | sda: not found in pathvec
Aug 28 16:21:34 | sda: mask = 0x5
Aug 28 16:21:34 | sda: dev_t = 8:0
Aug 28 16:21:34 | sda: size = 554287104
Aug 28 16:21:34 | sda: subsystem = scsi
Aug 28 16:21:34 | sda: vendor = IBM
Aug 28 16:21:34 | sda: product = IPR-0 5EC2A900
Aug 28 16:21:34 | sda: rev =
Aug 28 16:21:34 | sda: h:b:t:l = 0:2:0:0
Aug 28 16:21:34 | sda: get_state
Aug 28 16:21:34 | sda: path checker = tur (controller setting)
Aug 28 16:21:34 | sda: state = running
Aug 28 16:21:34 | sda: state = 3
     0:2:0:0 sda 8:0 -1 undef ready IBM,IPR-0 5EC2A900 running
Aug 28 16:21:34 | sda: mask = 0x8
Aug 28 16:21:34 | sda: prio = alua (controller setting)
Aug 28 16:21:34 | sda: prio args = (null) (controller setting)
Aug 28 16:21:34 | sda: alua prio = 130
| `- 0:2:0:0 sda 8:0 active ready running

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: multipath-tools 0.5.0-7ubuntu3
ProcVersionSignature: User Name 4.1.0-3.3-generic 4.1.3
Uname: Linux 4.1.0-3-generic ppc64le
ApportVersion: 2.18-0ubuntu7
Architecture: ppc64el
Date: Fri Aug 28 16:15:26 2015
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcLoadAvg: 0.01 0.19 0.17 1/1086 13536
ProcLocks:
 1: POSIX ADVISORY WRITE 2075 00:13:522 0 EOF
 2: POSIX ADVISORY WRITE 3326 00:13:746 0 EOF
 3: POSIX ADVISORY WRITE 2092 00:13:721 0 EOF
 4: FLOCK ADVISORY WRITE 2085 00:13:716 0 EOF
ProcSwaps:
 Filename Type Size Used Priority
 /swap.img file 8388544 0 -1
ProcVersion: Linux version 4.1.0-3-generic (buildd@fisher03) (gcc version 4.9.3 (User Name 4.9.3-2ubuntu1) ) #3-User Name SMP Tue Jul 28 12:23:44 UTC 2015
SourcePackage: multipath-tools
UpgradeStatus: No upgrade log present (probably fresh install)
cpu_cores: Number of cores present = 20
cpu_coreson: Number of cores online = 20
cpu_smt: SMT=8