HPE 3PAR: In multi host env, multi-detach works partially if volume is attached to instances from separate hosts
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Cinder |
Fix Released
|
Medium
|
Raghavendra Tilay |
Bug Description
1. IMPACT:
In multi host environment, multi-detach works partially & later volume cannot be deleted.
2. DETAILS & ROOT CAUSE:
Consider below scenario:
Host-A Host-B
| |
Instance1 Instance2
\ /
Volume
|
HPE Array
The volume is attached to instances present on different hosts.
During attach operation, separate vlun entry is created on array for each host.
When detach operation is performed from Host-A, it is checked if this volume has any other attachments.
If yes, then vlun entry of Host-A is not deleted.
This is becuase as per existing logic, it is assumed that volume is attached to multiple instances on same host;
and vlun entries would be deleted on last detach operation only.
Thus vlun entry of Host-A remains as it is on array.
When detach operation is performed from Host-B, it is observed that this volume does NOT have any other attachment.
vlun entry of Host-B is deleted.
Later when someone tries to delete volume, error is displayed:
Since vlun entry of Host-A exists, the volume cannot be deleted.
3. LOGS:
(i) detach from Host-A:
2021-11-23 09:33:18.860 42 INFO cinder.
2021-11-23 09:33:19.206 42 INFO cinder.
(ii) detach from Host-B:
Note: vlun entry is deleted, but it is not captured in INFO logs.
2021-11-23 09:48:15.633 44 INFO cinder.
(iii) During delete volume:
2021-11-23 09:59:42.326 42 ERROR cinder.
2021-11-23 09:59:42.350 42 ERROR cinder.
4. SOLUTION:
During detach operation, hostname is checked.
If volume is attached to instances present on same host, then flow is same as earlier i.e vlun entry is deleted only if this is last detach.
If volume is attached to instances present on separate hosts, vlun entry of only that host is deleted.
Thus in multi host env, vlun entries of each host would be deleted separately upon each detach operation; and later volume can be deleted.
description: | updated |
description: | updated |
description: | updated |
description: | updated |
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description: | updated |
description: | updated |
description: | updated |
description: | updated |
Changed in cinder: | |
assignee: | nobody → Raghavendra Tilay (raghavendrat) |
tags: | added: 3par hpe multiattach |
Changed in cinder: | |
importance: | Undecided → Medium |
Fix proposed to branch: master /review. opendev. org/c/openstack /cinder/ +/824911
Review: https:/