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 -- firstname.lastname@example.org To unsubscribe send an email to devel-le...@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://email@example.com/message/LAQR3RW4RMTUNFUXL5T4HWLPKXJKEC3Y/