Ceph/Swift find_disk.py fails to find GPT disklabels on some systems

[Paul Bourke]

Possibly (unconfirmed) due to a bug in some older versions of udev (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=681809), Im seeing some systems where the filesystem label applied to a GPT partition is not available, resulting in find_disks being unable to find the disk for use by Ceph/Swift. One such distro I'm seeing this on is oraclelinux 6 (based on rhel 6), though am positive I've seen it on newer distros in the past.

"""
# parted /dev/sdb -s -- mklabel gpt mklabel KOLLA_CEPH_OSD_BOOTSTRAP 1 -1
# parted /dev/sdb print
Model: ORACLE SSM (scsi)
Disk /dev/sdb: 8011MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags
 1 1049kB 8010MB 8009MB KOLLA_CEPH_OSD_BOOTSTRAP

# ls -l /dev/disk/
total 0
drwxr-xr-x 2 root root 380 May 24 12:32 by-id
drwxr-xr-x 2 root root 60 May 24 12:32 by-parttypeuuid
drwxr-xr-x 2 root root 60 May 24 12:32 by-partuuid
drwxr-xr-x 2 root root 240 May 24 12:32 by-path
drwxr-xr-x 2 root root 140 May 24 12:32 by-uuid
"""

In the above scenario the the label is applied as normal, but /dev/disk/by-partlabel is missing. If this is indeed the result of a bug in udev, we a few potential options:

1) figure out a workaround
2) update find_disks to allow alternative methods of finding disks
3) declare kolla does not support older distros

[OpenStack Infra (hudson-openstack)]

Change abandoned by Paul Bourke (<email address hidden>) on branch: master
Review: https://review.openstack.org/335046
Reason: dupe of 334970

[OpenStack Infra (hudson-openstack)]

Change abandoned by Paul Bourke (<email address hidden>) on branch: master
Review: https://review.openstack.org/334970
Reason: Thanks for the reviews on this all.

After discussing all the different partition schemes allowed by the existing label based approach, I've concluded this patch is not a good substitute. What Steve has in https://review.openstack.org/#/c/326609/ solves my particular problem, though we may need to revisit this if udev continues to cause problems.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/326609
Committed: https://git.openstack.org/cgit/openstack/kolla/commit/?id=cadf8afdcf4c1d56892b6d708003066e11711c5f
Submitter: Jenkins
Branch: master

commit cadf8afdcf4c1d56892b6d708003066e11711c5f
Author: Stephen Hindle <email address hidden>
Date: Tue Jun 7 09:07:34 2016 -0700

    Read GPT label using sgdisk rather than udev

    The Ceph osd bootstrap/startup logic depends upon reading/writing
    partition names. Some older versions of udev have trouble reading these
    (/dev/disk/by-label is missing).

    To work around this, we shell out to sgdisk and scrape the partition
    name data directly.

    Co-authored-by: Paul Bourke <email address hidden>
    Closes-Bug: 1585185
    Change-Id: I362b3f8e91de79687fc84e256996fbcaf303b6af

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/kolla 3.0.0.0b2 development milestone.