VDSM Hooks during migration
Dear oVIrt, Would you be so kind to help me/tell me or point me how to find which Hooks, and in which order, are triggered when VM is being migrated? Kindly awaiting your reply. — — — Met vriendelijke groet / Kind regards, Marko Vrgotic
"Vrgotic, Marko" <M.Vrgotic@activevideo.com> writes:
Would you be so kind to help me/tell me or point me how to find which Hooks, and in which order, are triggered when VM is being migrated?
See "VDSM and Hooks" appendix of oVirt Admin Guide: https://ovirt.org/documentation/admin-guide/appe-VDSM_and_Hooks.html Regards, Milan
Hi Milan, Thank you, I was aware of the page. What I am aiming for is following: We have a nauseate hook which deletes dns records from DNS server, for of a VM “destroyed”. That is just as we wanted it, except in a case of Migration, which is also a “destructive” action, looking from perspective of a Hypervisor. I was testing an order of Hooks triggered when I issue VM Migrate, in order to discover which Hook I can use to trigger update of the records for a VM that is Migrated. Seems that “after_vm_destroy” is the last in order hook to be executed when VM is migrated, and I wanted to verify that. How come that there is no hook which enables VM start or continue on a destination hypervisor, after VM is migrated? Or am I missing something? Sent from my iPhone
On 26 Aug 2019, at 17:30, Milan Zamazal <mzamazal@redhat.com> wrote:
"Vrgotic, Marko" <M.Vrgotic@activevideo.com> writes:
Would you be so kind to help me/tell me or point me how to find which Hooks, and in which order, are triggered when VM is being migrated?
See "VDSM and Hooks" appendix of oVirt Admin Guide:
https://ovirt.org/documentation/admin-guide/appe-VDSM_and_Hooks.html
Regards, Milan
"Vrgotic, Marko" <M.Vrgotic@activevideo.com> writes:
What I am aiming for is following: We have a nauseate hook which deletes dns records from DNS server, for of a VM “destroyed”. That is just as we wanted it, except in a case of Migration, which is also a “destructive” action, looking from perspective of a Hypervisor. I was testing an order of Hooks triggered when I issue VM Migrate, in order to discover which Hook I can use to trigger update of the records for a VM that is Migrated.
Seems that “after_vm_destroy” is the last in order hook to be executed when VM is migrated, and I wanted to verify that.
Hi Marko, I see, I understand now what's your problem. after_vm_destroy is called on the source while after_vm_migrate_destination on the destination and I don't think there is any guarantee in which order they are mutually called.
How come that there is no hook which enables VM start or continue on a destination hypervisor, after VM is migrated? Or am I missing something?
after_vm_migrate_destination is called on the destination, but see above. A possible solution could be to look in the domain XML passed to after_vm_destroy, there should be an exit reason in the metadata section. If the reason is migration, then you can skip your delete action. Regards, Milan
Milan Zamazal <mzamazal@redhat.com> writes:
"Vrgotic, Marko" <M.Vrgotic@activevideo.com> writes:
What I am aiming for is following: We have a nauseate hook which deletes dns records from DNS server, for of a VM “destroyed”. That is just as we wanted it, except in a case of Migration, which is also a “destructive” action, looking from perspective of a Hypervisor. I was testing an order of Hooks triggered when I issue VM Migrate, in order to discover which Hook I can use to trigger update of the records for a VM that is Migrated.
Seems that “after_vm_destroy” is the last in order hook to be executed when VM is migrated, and I wanted to verify that.
Hi Marko, I see, I understand now what's your problem. after_vm_destroy is called on the source while after_vm_migrate_destination on the destination and I don't think there is any guarantee in which order they are mutually called.
How come that there is no hook which enables VM start or continue on a destination hypervisor, after VM is migrated? Or am I missing something?
after_vm_migrate_destination is called on the destination, but see above. A possible solution could be to look in the domain XML passed to after_vm_destroy, there should be an exit reason in the metadata section. If the reason is migration, then you can skip your delete action.
Hm, it seems there is no exit info after migration. Another idea is to put something into after_vm_migrate_source hook that would prevent the record deletion.
Hey Milan, I guess we will have to look into it further. Thank you. Sent from my iPhone
On 27 Aug 2019, at 11:39, Milan Zamazal <mzamazal@redhat.com> wrote:
Milan Zamazal <mzamazal@redhat.com> writes:
"Vrgotic, Marko" <M.Vrgotic@activevideo.com> writes:
What I am aiming for is following: We have a nauseate hook which deletes dns records from DNS server, for of a VM “destroyed”. That is just as we wanted it, except in a case of Migration, which is also a “destructive” action, looking from perspective of a Hypervisor. I was testing an order of Hooks triggered when I issue VM Migrate, in order to discover which Hook I can use to trigger update of the records for a VM that is Migrated.
Seems that “after_vm_destroy” is the last in order hook to be executed when VM is migrated, and I wanted to verify that.
Hi Marko, I see, I understand now what's your problem. after_vm_destroy is called on the source while after_vm_migrate_destination on the destination and I don't think there is any guarantee in which order they are mutually called.
How come that there is no hook which enables VM start or continue on a destination hypervisor, after VM is migrated? Or am I missing something?
after_vm_migrate_destination is called on the destination, but see above. A possible solution could be to look in the domain XML passed to after_vm_destroy, there should be an exit reason in the metadata section. If the reason is migration, then you can skip your delete action.
Hm, it seems there is no exit info after migration. Another idea is to put something into after_vm_migrate_source hook that would prevent the record deletion.
and Thank you for the update, it’s good to re-read pages once in a while. Sent from my iPhone
On 26 Aug 2019, at 17:30, Milan Zamazal <mzamazal@redhat.com> wrote:
"Vrgotic, Marko" <M.Vrgotic@activevideo.com> writes:
Would you be so kind to help me/tell me or point me how to find which Hooks, and in which order, are triggered when VM is being migrated?
See "VDSM and Hooks" appendix of oVirt Admin Guide:
https://ovirt.org/documentation/admin-guide/appe-VDSM_and_Hooks.html
Regards, Milan
participants (2)
-
Milan Zamazal -
Vrgotic, Marko