Bug 1946995

Summary: Provide documentation for removing stale LUNs
Product: Red Hat Enterprise Virtualization Manager Reporter: Vojtech Juranek <vjuranek>
Component: DocumentationAssignee: Donna DaCosta <ddacosta>
Status: CLOSED CURRENTRELEASE QA Contact: rhev-docs <rhev-docs>
Severity: unspecified Docs Contact:
Priority: high    
Version: 4.4.0CC: aefrat, ctomasko, ddacosta, emarcus, eshames, lsurette, mavital, mburman, mhicks, michal.skrivanek, mkalinin, rhoch, sgoodman, srevivo
Target Milestone: ovirt-4.4.9Keywords: Documentation
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Hardware: Unspecified   
OS: Unspecified   
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Last Closed: 2021-11-16 22:00:38 UTC Type: Bug
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oVirt Team: Docs RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 1310330    
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Description Vojtech Juranek 2021-04-07 13:03:06 UTC 
Description of problem:
Provide documentation how to remove stale LUNs from the hosts (BZ #1310330). 

The process is as follows:
1. put SD into maintenance
2. detach SD
3. remove SD
4. remove/unzone LUN from storage server
5. run ansible playbook to remove stale LUNs from the hosts

Point 1.-3. are standard operation done via oVirt UI (ovirt ansible playbook ...).

Point 4. has to be done by administrator of storage server. The documentation should include explanation that oVirt/RHEV doesn't manager iSCSI servers and therefore cannot do the LUN removal itself. Similar to creating iSCSI SD oVirt expects LUNs forming SD already exists on storage server and doesn't create them during SD creation, during removal oVirt just removes SD and left LUNs on storage server.

As for point 5., ansible playbook for it is remove_mpath_device.yml, placed in example dir ovirt-ansible-collection and usage is as follows:

ansible-playbook --extra-vars "lun=<LUN>" /usr/share/doc/ovirt-ansible-collection/examples/remove_mpath_device.yml

where <LUN> should be replaced by the LUN forming SD, which was removed in step 4.

If the LUN is not removed from storage server (step 4.), step 5. will succeed, but as vdsm does iSCIS rescans on various occasions, the stale LUN will appear on the hosts again (after next iSCSI rescan).
Comment 1 Michal Skrivanek 2021-06-01 14:18:23 UTC 
(In reply to Vojtech Juranek from comment #0)
> Description of problem:
> Provide documentation how to remove stale LUNs from the hosts (BZ #1310330). 
> 
> The process is as follows:
> 1. put SD into maintenance
> 2. detach SD
> 3. remove SD
> 4. remove/unzone LUN from storage server
> 5. run ansible playbook to remove stale LUNs from the hosts
> 
> Point 1.-3. are standard operation done via oVirt UI (ovirt ansible playbook
> ...).
> 
> Point 4. has to be done by administrator of storage server. The
> documentation should include explanation that oVirt/RHEV doesn't manager
> iSCSI servers and therefore cannot do the LUN removal itself. Similar to
> creating iSCSI SD oVirt expects LUNs forming SD already exists on storage
> server and doesn't create them during SD creation, during removal oVirt just
> removes SD and left LUNs on storage server.
> 
> As for point 5., ansible playbook for it is remove_mpath_device.yml, placed
> in example dir ovirt-ansible-collection and usage is as follows:
> 
> ansible-playbook --extra-vars "lun=<LUN>"
> /usr/share/doc/ovirt-ansible-collection/examples/remove_mpath_device.yml

we shouldn't make examples a mandatory part of supported feature.
Comment 19 Donna DaCosta 2021-11-16 22:00:38 UTC 
Published: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.4/html-single/administration_guide/index#Removing_stale_LUNs