Bug 1973271

Summary:	[RBD] Disable thick PVC snapshot to thin PVC restore and thin PVC snapshot to thick PVC restore
Product:	[Red Hat Storage] Red Hat OpenShift Container Storage	Reporter:	Jilju Joy <jijoy>
Component:	csi-driver	Assignee:	Nobody <nobody>
Status:	VERIFIED ---	QA Contact:	Jilju Joy <jijoy>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	4.8	CC:	muagarwa, nberry, tdesala
Target Milestone:	---	Keywords:	AutomationTriaged
Target Release:	OCS 4.8.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	4.8.0-432.ci	Doc Type:	No Doc Update
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Jilju Joy 2021-06-17 14:11:48 UTC

Description of problem (please be detailed as possible and provide log
snippests):
With the fix of the bug #1959793, thick PVC snapshot to thick PVC restore and thick PVC to thick PVC clone will be enabled.

Currently all restored RBD PVCs are thin provisioned despite the fact  that the storage class used to restore the snapshot have thick provision enabled or not.

As per the discussions done so far, disabling the scenarios given below will avoid any unforeseen issue even after the fix of #1959793 and also helps smooth 
smooth functioning of thick to thick restore and clone.
1) thick PVC snapshot - thin PVC restore 
2) thin PVC snapshot - thick PVC restore
An upstream PR is already present to which will disable this.
https://github.com/ceph/ceph-csi/pull/2174

Version of all relevant components (if applicable):
OCS 4.8

Comment 6 Mudit Agarwal 2021-06-24 13:21:30 UTC

Though we have disabled the switch between thick to thin and vice versa but it is an open issue in case that is also a requirement.
Tagging this as a known issue, till we have some clarity on the same.

Comment 7 Jilju Joy 2021-07-06 12:48:20 UTC

Verified in version:
ocs-operator.v4.8.0-443.ci
OCP 4.8.0-0.nightly-2021-07-04-112043

Error while creating a thin PVC from the snapshot of a RBD thick PVC:

Generated from openshift-storage.rbd.csi.ceph.com_csi-rbdplugin-provisioner-5f656cc8f7-t9z6l_2f55c1c2-b209-41fd-a91d-2e27956c7ace

failed to provision volume with StorageClass "ocs-storagecluster-ceph-rbd": rpc error: code = InvalidArgument desc = cannot restore from snapshot ocs-storagecluster-cephblockpool/csi-vol-aa7a66df-de52-11eb-b0f8-0a580a800029@csi-snap-c45fabfc-de52-11eb-b0f8-0a580a800029: cannot create thin volume from thick volume "ocs-storagecluster-cephblockpool/csi-snap-c45fabfc-de52-11eb-b0f8-0a580a800029"


Error while creating a thick PVC from the snapshot of a RBD thin PVC:

Generated from openshift-storage.rbd.csi.ceph.com_csi-rbdplugin-provisioner-5f656cc8f7-t9z6l_2f55c1c2-b209-41fd-a91d-2e27956c7ace

failed to provision volume with StorageClass "ocs-storagecluster-ceph-rbd-thick": rpc error: code = InvalidArgument desc = cannot restore from snapshot ocs-storagecluster-cephblockpool/csi-vol-2cc20945-de55-11eb-b0f8-0a580a800029@csi-snap-31b3116a-de55-11eb-b0f8-0a580a800029: cannot create thick volume from thin volume "ocs-storagecluster-cephblockpool/csi-snap-31b3116a-de55-11eb-b0f8-0a580a800029"


Verified that switch between thin to thick and vice versa while restoring a snapshot is disabled.
The restored PVC will remain in pending status. A better approach will be not not attempt provision the volume instead of keeping the PVC in pending state. Considering the fact that the thick-thin and thin-thick switching will be enabled when the feature become fully supported, it is okay to keep this behavior in OCS 4.8.