6:29 a.m.
Any ideas
From: "Vrgotic, Marko" <M.Vrgotic(a)activevideo.com>
Date: Friday, 27 September 2019 at 17:26
To: "users(a)ovirt.org" <users(a)ovirt.org>
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/>
</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