So from what I was able to see in hotplugDisk example, for CDs I would have to do similar: 1. parse disk params from stored xml metadata 2. call prepareVolumePath with these params (skip normalizeVdsmImg) 3. call updateDriveIndex (skip validating whether volume has leases) 4. drive.getXML() and then hooks.before_disk_hotplug with it 5. call attachDevice with drive XML and handle possible errors I am not sure, however, whether we need what "else" does in hotplugDisk (vm.py line 3468)... Looking forward to hearing your opinions, Fedor ----- Original Message ----- From: "Fedor Gavrilov" <fgavrilo@redhat.com> To: "devel" <devel@ovirt.org> Sent: Monday, June 22, 2020 4:37:59 PM Subject: [ovirt-devel] implementing hotplugCd/hotunplugCd in vdsm Hey, So in an attempt to fix change CD functionality we discovered a few other potential issues and what Nir suggested was to implement two [somewhat] new functions in VDSM: hotplug and hotunplug for CDs similar to how it works for normal disks now. Existing changeCD function will be left as is for backwards compatibility. As I found out, engine already calculates iface and index before invoking VDSM functions, so we will just pass these along with PDIV to the VDSM. Suggested flow is, let me quote:
So the complete change CD flow should be:
1. get the previous drivespec from vm metadata 2. prepare new drivespec 3. add new drivespec to vm metadata 4. attach a new device to vm 5. teardown the previous drivespec 6. remove previous drivespec from vm metadata
When the vm is stopped, it must do:
1. get drive spec from vm metadata 2. teardown drivespec
During attach, there are interesting races: - what happens if vdsm crashes after step 2? who will teardown the volume? maybe you need to add the new drivespec to the metadata first, before preparing it. - what happens if attach failed? who will remove the new drive from the metadata?
Now, what makes hotplugDisk/hotunplugDisk different? From what I understand, the flow is same there, so what difference is there as far as VDSM is concerned? If none, this means if I more or less copy that code, changing minor details and data accordingly for CDs, this should work, shouldn't it? Thanks! Fedor _______________________________________________ Devel mailing list -- devel@ovirt.org To unsubscribe send an email to devel-leave@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/devel@ovirt.org/message/LAQR3RW4RMTUNF...