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#!/usr/bin/env python3
"""
This service waits for the guest agent lifecycle event and reissues
guest agent calls to modify the cpu count according to the metadata
set by guest-vcpu.py example
"""
import libvirt
import threading
from xml.dom import minidom
import time
from argparse import ArgumentParser
uri = "qemu:///system"
customXMLuri = "guest-cpu.python.libvirt.org"
connectRetryTimeout = 5
class workerData:
def __init__(self):
self.doms = list()
self.conn = None
self.cond = threading.Condition()
def notify(self):
self.cond.acquire()
self.cond.notify()
self.cond.release()
def waitNotify(self):
self.cond.acquire()
self.cond.wait()
self.cond.release()
def addDomainNotify(self, dom):
self.doms.append(dom)
self.notify()
def closeConnectNotify(self):
conn = self.conn
self.conn = None
conn.close()
self.notify()
def setConnect(self, conn):
self.conn = conn
def hasConn(self):
return self.conn is not None
def hasDom(self):
return len(self.doms) > 0
def getDom(self):
return self.doms.pop()
def setDoms(self, doms):
self.doms = doms
def virEventLoopNativeRun():
while True:
libvirt.virEventRunDefaultImpl()
def handleAgentLifecycleEvent(conn, dom, state, reason, opaque):
if state == libvirt.VIR_CONNECT_DOMAIN_EVENT_AGENT_LIFECYCLE_STATE_CONNECTED:
opaque.addDomainNotify(dom)
def handleConnectClose(conn, reason, opaque):
print('Disconnected from ' + uri)
opaque.closeConnectNotify()
def handleLibvirtLibraryError(opaque, error):
pass
def processAgentConnect(dom):
try:
cpus = dom.metadata(libvirt.VIR_DOMAIN_METADATA_ELEMENT, customXMLuri, libvirt.VIR_DOMAIN_AFFECT_LIVE)
doc = minidom.parseString(cpus)
ncpus = int(doc.getElementsByTagName('ncpus')[0].getAttribute('count'))
except Exception:
return
try:
dom.setVcpusFlags(ncpus, libvirt.VIR_DOMAIN_AFFECT_LIVE | libvirt.VIR_DOMAIN_VCPU_GUEST)
print("set vcpu count for domain " + dom.name() + " to " + str(ncpus))
except Exception:
print("failed to set vcpu count for domain " + dom.name())
def work():
data = workerData()
print("Using uri: " + uri)
while True:
if not data.hasConn():
try:
conn = libvirt.open(uri)
except libvirt.libvirtError:
print('Failed to connect to ' + uri + ', retry in ' + str(connectRetryTimeout)) + ' seconds'
time.sleep(connectRetryTimeout)
continue
print('Connected to ' + uri)
data.setConnect(conn)
conn.registerCloseCallback(handleConnectClose, data)
conn.setKeepAlive(5, 3)
conn.domainEventRegisterAny(None,
libvirt.VIR_DOMAIN_EVENT_ID_AGENT_LIFECYCLE,
handleAgentLifecycleEvent,
data)
data.setDoms(conn.listAllDomains(libvirt.VIR_CONNECT_LIST_DOMAINS_ACTIVE))
while data.hasConn() and data.hasDom():
processAgentConnect(data.getDom())
data.waitNotify()
def main():
libvirt.virEventRegisterDefaultImpl()
libvirt.registerErrorHandler(handleLibvirtLibraryError, None)
worker = threading.Thread(target=work)
worker.setDaemon(True)
worker.start()
eventLoop = threading.Thread(target=virEventLoopNativeRun)
eventLoop.setDaemon(True)
eventLoop.start()
while True:
time.sleep(1)
if __name__ == "__main__":
parser = ArgumentParser(description=__doc__)
parser.add_argument("uri", nargs="?", default=uri)
args = parser.parse_args()
uri = args.uri
main()
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