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Bug 1033185 - [RFE][nova]: a shared volume can be accessed by many instances
[RFE][nova]: a shared volume can be accessed by many instances
Product: Red Hat OpenStack
Classification: Red Hat
Component: openstack-nova (Show other bugs)
Unspecified Unspecified
urgent Severity high
: Upstream M2
: 14.0 (Rocky)
Assigned To: Matthew Booth
Archit Modi
upstream_milestone_none upstream_defi...
: FutureFeature, Triaged
Depends On:
Blocks: 1033180 1281573 1339072 1442136 1476900 1478186 1496484 1521118 1613486 1624971 1022045 1552736
  Show dependency treegraph
Reported: 2013-11-21 11:26 EST by Stephen Gordon
Modified: 2018-11-14 11:04 EST (History)
29 users (show)

See Also:
Fixed In Version: openstack-nova-18.0.0-0.20180710150340.8469fa7
Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: 1033178
: 1552736 (view as bug list)
Last Closed:
Type: Feature Request
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

External Trackers
Tracker ID Priority Status Summary Last Updated
OpenStack gerrit 304681 None None None 2016-06-21 16:21 EDT
OpenStack gerrit 373203 None None None 2016-11-28 10:47 EST

  None (edit)
Description Stephen Gordon 2013-11-21 11:26:52 EST
Cloning to Nova as there are impacts here too. No Nova-specific blueprint exists (to my knowledge) covering these impacts at this time.

+++ This bug was initially created as a clone of Bug #1033178 +++

Cloned from launchpad blueprint https://blueprints.launchpad.net/cinder/+spec/shared-volume.


Provide the ability to attach a single volume to multiple instances simultaneously.  In order to do this R/W there are a number of issues involved with respect to data corruption etc.  As a first pass it would be very useful to introduce a Read Only option that could be specified during attach and used to allow simultaneous attach to multiple instances.

Most of this will require work in Nova/Compute but there will need to be some comprehension added to Cinder, and perhaps the ability to mark a volume as Read Only might be useful as well.

This R/O volumes could be especially useful for things like Images and even D2D backups.  

There's also a need for FC environments to multi-attach in general.

Specification URL (additional information):

Comment 2 Stephen Gordon 2013-11-27 15:39:17 EST
I'm actually currently working this against https://blueprints.launchpad.net/cinder/+spec/multi-attach-volume but both it and the blueprint in the description overlap.
Comment 3 Dave Allan 2013-12-11 22:16:34 EST
Note that one of the use cases here is clusters with SCSI3 persistent reservation based fencing, which expands the scope quite a bit to include virtio-scsi and NPIV.  Libvirt is most of the way through the implementation of expanded support for NPIV which might help here.
Comment 6 Mike McCune 2016-03-28 19:11:51 EDT
This bug was accidentally moved from POST to MODIFIED via an error in automation, please see mmccune@redhat.com with any questions
Comment 8 Stephen Gordon 2016-07-07 12:15:26 EDT
Missed Newton approvals, moving to Ocata.
Comment 11 Stephen Gordon 2016-10-28 14:15:31 EDT
Moving to Lee initially based on a discussion we had today. This feature and issues related to it, among others, led to discussion of a significant update/rewrite of the way Cinder and Nova work together to attach volumes at the Barcelona OpenStack summit:


The long and the short of it is there is quite a lot of work to do here, I would like to keep this on our RHOSP 11/Ocata work list to ensure forward progress but am not confident of 100% completion of the end to end feature in that time frame.
Comment 25 Stephen Gordon 2017-07-25 10:27:41 EDT
Hi Matt,

How has this been tracking upstream through Pike? How much of it remains outstanding?


Comment 37 Matthew Booth 2018-06-05 12:39:33 EDT
Upstream cinder has support for multiattach on the following backend drivers:


A couple of things to note:

storwize_svc appears to publish the multiattach capability if the storwize_svc_multihostmap_enabled config option is set to True, but it's marked deprecated and the help text says it has no effect.

There's a cinder config option for netapp called netapp_enable_multiattach which seems to relate to an internal netapp multiattach feature, and does not enable cinder multiattach.

It would be good to get independent confirmation of the above, as I have created the above primary from grep.

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