yahoo-eng-team team mailing list archive

[Feodor Tersin <ftersin@xxxxxxxxxxx>]

Public bug reported:

If an image has several volume in bdm, and a user adds one more volume
for boot operation, then the new volume is not just added to a volume
list, but becomes the second device. This can lead to problems if the
image root device has various soft which settings point to other
volumes.

For example:
1 the image is a snapshot of a volume backed instance which had vda and vdb volumes
2 the instance had an sql server, which used both vda and vdb for its database
3 if a user runs a new instance from the image, either device names are restored (with xen), or they're reassigned (libvirt) to the same names, because the order of devices, which are passed in libvirt, is the same as it was for the original instance
4 if a user runs a new instance, adding a new volume, the volume list becomes vda, new, vdb
5 in this case libvirt reassings device names to vda=vda, new=vdb, vdb=vdc
6 as a result the sql server will not find its data on vdb

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1489442

Title:
  Invalid order of volumes with adding a volume in boot operation

Status in OpenStack Compute (nova):
  New

Bug description:
  If an image has several volume in bdm, and a user adds one more volume
  for boot operation, then the new volume is not just added to a volume
  list, but becomes the second device. This can lead to problems if the
  image root device has various soft which settings point to other
  volumes.

  For example:
  1 the image is a snapshot of a volume backed instance which had vda and vdb volumes
  2 the instance had an sql server, which used both vda and vdb for its database
  3 if a user runs a new instance from the image, either device names are restored (with xen), or they're reassigned (libvirt) to the same names, because the order of devices, which are passed in libvirt, is the same as it was for the original instance
  4 if a user runs a new instance, adding a new volume, the volume list becomes vda, new, vdb
  5 in this case libvirt reassings device names to vda=vda, new=vdb, vdb=vdc
  6 as a result the sql server will not find its data on vdb

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