[ovirt-users] Re: How to pass parameters between VDSM Hooks domxml in single run

On 3 Oct 2019, at 12:50, Vrgotic, Marko <M.Vrgotic(a)activevideo.com&gt; wrote: Hi Michal, Thank you. Would you be so kind to provide me with additional clarification? > you can’t just add a random tag into libvirt xml in a random place, it will be dropped by libvirt. I understand, thank you. About persistence of added tag, it was not used/written during 1xMigration, but it was present in domxml in 2xMigration. > you can add it to metadata though. we use that for ovirt-specific information Can you please provide some more HowTo/HowNotTo information? Can we manipulate the tag in metadata section in each iteration? I assume VM metadata shared/communicated between Hosts or read and provided to Hosts by oVirt-Engine? In short we are trying to achive: - start migration - ex: 10_create_tag inserts <is_migration/> tag into XML metadata section <= maybe we can use before_vm_migration_source hook - migration is finished and after_vm_destroy hooks comes to turn: - ex: 20_nsupdate reads the metadata and: - if tag <is_migrated/> exists, do not run dns update, but remove the tag - if tag <is_migrated/> does not exists, run dns update and remove the tag

Kindly awaiting your reply. Marko Vrgotic On 03/10/2019, 12:27, "Michal Skrivanek" <michal.skrivanek(a)redhat.com&gt; wrote: > On 2 Oct 2019, at 13:29, Vrgotic, Marko <M.Vrgotic(a)activevideo.com&gt; wrote: > > Any ideas > > From: "Vrgotic, Marko" <M.Vrgotic(a)activevideo.com&gt; > Date: Friday, 27 September 2019 at 17:26 > To: &quot;users(a)ovirt.org&quot; <users(a)ovirt.org&gt; > Subject: How to pass parameters between VDSM Hooks domxml in single run > > Dear oVIrt, > > A while ago we discussed on ways to change/update content of parameters of domxml in certain action. > > As I mentioned before, we have added the VDSMHook 60_nsupdate which removes the DNS record entries when a VM is destroyed: > > … > domxml = hooking.read_domxml() > name = domxml.getElementsByTagName('name')[0] > name = " ".join(name.nodeValue for name in name.childNodes if name.nodeType == name.TEXT_NODE) > nsupdate_commands = """server {server_ip} > update delete {vm_name}.example.com a > update delete {vm_name}. example.com aaaa > update delete {vm_name}. example.com txt > send > """.format(server_ip="172.16.1.10", vm_name=name) > … > > The goal: > However, we did not want to execute remove dns records when VM is only migrated. Since its considered a “destroy” action we took following approach. > • In state “before_vm_migrate_source add hook which will write flag “is_migration” to domxml > • Once VM is scheduled for migration, this hook should add the flag “is_migration” to domxml > • Once 60_nsupdate is triggered, it will check for the flag and if there, skip executing dns record action, but only remove the flag “is_migration” from domxml of the VM > > … > domxml = hooking.read_domxml() > migration = domxml.createElement("is_migration") > domxml.getElementsByTagName("domain")[0].appendChild(migration) > logging.info("domxml_updated {}".format(domxml.toprettyxml())) > hooking.write_domxml(domxml) > … > > When executing first time, we observed that flag “ > > <name>hookiesvm</name> > <uuid>fcfa66cb-b251-43a3-8e2b-f33b3024a749</uuid> > <metadata xmlns:ns0="http://ovirt.org/vm/tune/1.0" xmlns:ns1="http://ovirt.org/vm/1.0"> > <ns0:qos/> > <ovirt-vm:vm xmlns:ovirt-vm="http://ovirt.org/vm/1.0"> > <ovirt-vm:clusterVersion>4.3</ovirt-vm:clusterVersion> > <ovirt-vm:destroy_on_reboot type="bool">False</ovirt-vm:destroy_on_reboot> > <ovirt-vm:launchPaused>false</ovirt-vm:launchPaused> > <ovirt-vm:memGuaranteedSize type="int">1024</ovirt-vm:memGuaranteedSize> > <ovirt-vm:minGuaranteedMemoryMb type="int">1024</ovirt-vm:minGuaranteedMemoryMb> > ...skipping... > <address bus="0x00" domain="0x0000" function="0x0" slot="0x09" type="pci"/> > </rng> > </devices> > <seclabel model="selinux" relabel="yes" type="dynamic"> > <label>system_u:system_r:svirt_t:s0:c169,c575</label> > <imagelabel>system_u:object_r:svirt_image_t:s0:c169,c575</imagelabel> > </seclabel> > <seclabel model="dac" relabel="yes" type="dynamic"> > <label>+107:+107</label> > <imagelabel>+107:+107</imagelabel> > </seclabel> > <is_migration/> you can’t just add a random tag into libvirt xml in a random place, it will be dropped by libvirt. you can add it to metadata though. we use that for ovirt-specific information > </domain> > is added to domxml, but was present once 60_nsupdate hook was executed. > > The question: How do we make sure that, when domxml is updated, that the update is visible/usable by following hook, in single run? How to pass these changes between hooks? > > Kindly awaiting your reply. > > > — — — > Met vriendelijke groet / Kind regards, > > Marko Vrgotic > > > _______________________________________________ > Users mailing list -- users(a)ovirt.org > To unsubscribe send an email to users-leave(a)ovirt.org > Privacy Statement: https://www.ovirt.org/site/privacy-policy/ > oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ > List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/IC4J6CAJUQO...