278 lines
9.5 KiB
Python
278 lines
9.5 KiB
Python
#!/usr/bin/env python3
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# VMInstance.py - Class implementing a PVC virtual machine and run by pvcd
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# Part of the Parallel Virtual Cluster (PVC) system
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#
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# Copyright (C) 2018 Joshua M. Boniface <joshua@boniface.me>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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###############################################################################
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import os, sys, uuid, socket, time, threading, libvirt, kazoo.client
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class VMInstance:
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def __init__(self, domuuid, zk, thishypervisor):
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# Passed-in variables on creation
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self.domuuid = domuuid
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self.zkey = '/domains/%s' % domuuid
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self.zk = zk
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self.thishypervisor = thishypervisor
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# These will all be set later
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self.hypervisor = None
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self.state = None
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self.instart = False
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self.instop = False
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self.inshutdown = False
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self.inmigrate = False
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self.inreceive = False
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self.dom = lookupByUUID(self.domuuid)
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# Watch for changes to the hypervisor field in Zookeeper
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@zk.DataWatch(self.zkey + '/hypervisor')
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def watch_hypervisor(data, stat, event=""):
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try:
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self.hypervisor = data.decode('ascii')
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except:
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return
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self.manage_vm_state()
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# Watch for changes to the state field in Zookeeper
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@zk.DataWatch(self.zkey + '/state')
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def watch_state(data, stat, event=""):
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try:
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self.state = data.decode('ascii')
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except:
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return
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self.manage_vm_state()
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# Get data functions
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def getstate(self):
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return self.state
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def gethypervisor(self):
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return self.hypervisor
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# Start up the VM
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def start_vm(self, xmlconfig):
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print(">>> %s - Starting VM" % self.domuuid)
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self.instart = True
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# Start up a new Libvirt connection
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libvirt_name = "qemu:///system"
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conn = libvirt.open(libvirt_name)
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if conn == None:
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print('>>> %s - Failed to open local libvirt connection.' % self.domuuid)
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self.instart = False
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return
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try:
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dom = conn.createXML(xmlconfig, 0)
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except libvirt.libvirtError as e:
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print('>>> %s - Failed to create VM' % self.domuuid)
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self.zk.set(self.zkey + '/state', 'stop'.encode('ascii'))
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if not self.domuuid in self.thishypervisor.domain_list:
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self.thishypervisor.domain_list.append(self.domuuid)
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conn.close()
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self.dom = dom
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self.instart = False
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# Stop the VM forcibly
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def stop_vm(self):
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print(">>> %s - Forcibly stopping VM" % self.domuuid)
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self.instop = True
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self.dom.destroy()
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if self.domuuid in self.thishypervisor.domain_list:
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try:
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self.thishypervisor.domain_list.remove(self.domuuid)
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except ValueError:
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pass
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self.zk.set(self.zkey + '/state', 'stop'.encode('ascii'))
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self.dom = None
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self.instop = False
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# Shutdown the VM gracefully
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def shutdown_vm(self):
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print(">>> %s - Gracefully stopping VM" % self.domuuid)
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self.inshutdown = True
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self.dom.shutdown()
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try:
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tick = 0
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while self.dom.state()[0] == libvirt.VIR_DOMAIN_RUNNING and tick < 60:
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tick += 1
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time.sleep(0.5)
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if tick >= 60:
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print(">>> %s - Shutdown timeout expired" % self.domuuid)
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self.stop_vm()
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self.inshutdown = False
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return
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except:
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pass
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if self.domuuid in self.thishypervisor.domain_list:
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try:
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self.thishypervisor.domain_list.remove(self.domuuid)
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except ValueError:
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pass
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self.zk.set(self.zkey + '/state', 'stop'.encode('ascii'))
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self.dom = None
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self.inshutdown = False
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def live_migrate_vm(self, dest_hypervisor):
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try:
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dest_conn = libvirt.open('qemu+tcp://%s/system' % self.hypervisor)
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if dest_conn == None:
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raise
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except:
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print('>>> %s - Failed to open connection to qemu+tcp://%s/system; aborting migration' % self.hypervisor)
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return 1
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try:
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target_dom = self.dom.migrate(dest_conn, libvirt.VIR_MIGRATE_LIVE, None, None, 0)
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if target_dom == None:
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raise
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print('>>> %s - Migrated successfully' % self.domuuid)
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except:
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dest_conn.close()
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print('>>> %s - Could not live migrate VM' % self.domuuid)
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return 1
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dest_conn.close()
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return 0
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# Migrate the VM to a target host
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def migrate_vm(self):
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self.inmigrate = True
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print('>>> %s - Migrating VM to %s' % (self.domuuid, self.hypervisor))
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migrate_ret = self.live_migrate_vm(self.hypervisor)
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if migrate_ret != 0:
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print('>>> %s - Could not live migrate VM; forcing away' % self.domuuid)
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self.shutdown_vm()
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time.sleep(0.5)
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else:
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try:
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self.thishypervisor.domain_list.remove(self.domuuid)
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except ValueError:
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pass
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self.inmigrate = False
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# Receive the migration from another host (wait until VM is running)
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def receive_migrate(self):
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print('>>> %s - Receiving migration' % self.domuuid)
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self.inreceive = True
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while True:
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self.dom = lookupByUUID(self.domuuid)
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if self.dom == None:
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time.sleep(0.2)
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continue
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if self.dom.state()[0] == libvirt.VIR_DOMAIN_RUNNING:
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break
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self.zk.set(self.zkey + '/state', 'start'.encode('ascii'))
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if not self.domuuid in self.thishypervisor.domain_list:
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self.thishypervisor.domain_list.append(self.domuuid)
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print('>>> %s - Migrated successfully' % self.domuuid)
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self.inreceive = False
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#
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# Main function to manage a VM (taking only self)
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#
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def manage_vm_state(self):
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# Check the current state of the VM
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try:
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if self.dom != None:
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running, reason = self.dom.state()
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else:
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raise
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except:
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running = libvirt.VIR_DOMAIN_NOSTATE
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# VM should be stopped
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if running == libvirt.VIR_DOMAIN_RUNNING and self.state == "stop" and self.hypervisor == self.thishypervisor.name and self.instop == False:
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self.stop_vm()
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# We got no state, so the VM is deleted and should be stopped
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elif running == libvirt.VIR_DOMAIN_NOSTATE:
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self.stop_vm()
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# VM should be shut down
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elif running == libvirt.VIR_DOMAIN_RUNNING and self.state == "shutdown" and self.hypervisor == self.thishypervisor.name and self.inshutdown == False:
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self.shutdown_vm()
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# VM should be migrated to this hypervisor
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elif running != libvirt.VIR_DOMAIN_RUNNING and self.state == "migrate" and self.hypervisor == self.thishypervisor.name and self.inreceive == False:
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self.receive_migrate()
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# VM should be migrated away from this hypervisor
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elif running == libvirt.VIR_DOMAIN_RUNNING and self.state == "migrate" and self.hypervisor != self.thishypervisor.name and self.inmigrate == False:
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self.migrate_vm()
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# VM is already running and should be
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elif running == libvirt.VIR_DOMAIN_RUNNING and self.state == "start" and self.hypervisor == self.thishypervisor.name:
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if not self.domuuid in self.thishypervisor.domain_list:
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self.thishypervisor.domain_list.append(self.domuuid)
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# VM should be started
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elif running != libvirt.VIR_DOMAIN_RUNNING and self.state == "start" and self.hypervisor == self.thishypervisor.name and self.instart == False:
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# Grab the domain information from Zookeeper
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domxml, domxmlstat = self.zk.get(self.zkey + '/xml')
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domxml = str(domxml.decode('ascii'))
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self.start_vm(domxml)
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# This function is a wrapper for libvirt.lookupByUUID which fixes some problems
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# 1. Takes a text UUID and handles converting it to bytes
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# 2. Try's it and returns a sensible value if not
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def lookupByUUID(tuuid):
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conn = None
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dom = None
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libvirt_name = "qemu:///system"
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# Convert the text UUID to bytes
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buuid = uuid.UUID(tuuid).bytes
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# Try
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try:
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# Open a libvirt connection
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conn = libvirt.open(libvirt_name)
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if conn == None:
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print('>>> %s - Failed to open local libvirt connection.' % self.domuuid)
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return dom
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# Lookup the UUID
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dom = conn.lookupByUUID(buuid)
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# Fail
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except:
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pass
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# After everything
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finally:
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# Close the libvirt connection
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if conn != None:
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conn.close()
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# Return the dom object (or None)
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return dom
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