384 lines
15 KiB
Python
384 lines
15 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, ansiiprint
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class VMInstance:
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# Initialization function
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def __init__(self, domuuid, zk, config, thishypervisor):
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# Passed-in variables on creation
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self.domuuid = domuuid
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self.zk = zk
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self.config = config
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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.inrestart = False
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self.inmigrate = False
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self.inreceive = False
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self.inshutdown = False
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self.instop = False
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self.dom = self.lookupByUUID(self.domuuid)
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# Watch for changes to the state field in Zookeeper
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@zk.DataWatch('/domains/{}/state'.format(self.domuuid))
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def watch_state(data, stat, event=""):
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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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def getdom(self):
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return self.dom
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# Start up the VM
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def start_vm(self):
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ansiiprint.echo('Starting VM', '{}:'.format(self.domuuid), 'i')
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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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ansiiprint.echo('Failed to open local libvirt connection', '{}:'.format(self.domuuid), 'e')
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self.instart = False
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return
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try:
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# Grab the domain information from Zookeeper
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xmlconfig = self.zk.get('/domains/{}/xml'.format(self.domuuid))[0].decode('ascii')
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dom = conn.createXML(xmlconfig, 0)
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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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ansiiprint.echo('Successfully started VM', '{}:'.format(self.domuuid), 'o')
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self.dom = dom
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except libvirt.libvirtError as e:
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ansiiprint.echo('Failed to create VM', '{}:'.format(self.domuuid), 'e')
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'stop'.encode('ascii'))
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self.dom = None
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conn.close()
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self.instart = False
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# Restart the VM
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def restart_vm(self):
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ansiiprint.echo('Restarting VM', '{}:'.format(self.domuuid), 'i')
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self.inrestart = 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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ansiiprint.echo('Failed to open local libvirt connection', '{}:'.format(self.domuuid), 'e')
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self.inrestart = False
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return
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try:
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self.shutdown_vm()
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self.start_vm()
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ansiiprint.echo('Successfully restarted VM', '{}:'.format(self.domuuid), 'o')
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except libvirt.libvirtError as e:
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ansiiprint.echo('Failed to restart VM', '{}:'.format(self.domuuid), 'e')
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii'))
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conn.close()
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self.inrestart = False
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# Stop the VM forcibly without updating state
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def terminate_vm(self):
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ansiiprint.echo('Terminating VM', '{}:'.format(self.domuuid), 'i')
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self.instop = True
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try:
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self.dom.destroy()
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except AttributeError:
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ansiiprint.echo('Failed to terminate VM', '{}:'.format(self.domuuid), 'e')
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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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ansiiprint.echo('Successfully terminated VM', '{}:'.format(self.domuuid), 'o')
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self.dom = None
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self.instop = False
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# Stop the VM forcibly
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def stop_vm(self):
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ansiiprint.echo('Forcibly stopping VM', '{}:'.format(self.domuuid), 'i')
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self.instop = True
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try:
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self.dom.destroy()
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except AttributeError:
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ansiiprint.echo('Failed to stop VM', '{}:'.format(self.domuuid), 'e')
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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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if self.inrestart == False:
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'stop'.encode('ascii'))
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ansiiprint.echo('Successfully stopped VM', '{}:'.format(self.domuuid), 'o')
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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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ansiiprint.echo('Gracefully stopping VM', '{}:'.format(self.domuuid), 'i')
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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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ansiiprint.echo('Shutdown timeout expired', '{}:'.format(self.domuuid), 'e')
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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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if self.inrestart == False:
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'stop'.encode('ascii'))
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ansiiprint.echo('Successfully shutdown VM', '{}:'.format(self.domuuid), 'o')
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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://{}/system'.format(self.hypervisor))
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if dest_conn == None:
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raise
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except:
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ansiiprint.echo('Failed to open connection to qemu+tcp://{}/system; aborting migration.'.format(self.hypervisor), '{}:'.format(self.domuuid), 'e')
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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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ansiiprint.echo('Successfully migrated VM', '{}:'.format(self.domuuid), 'o')
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except:
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dest_conn.close()
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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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ansiiprint.echo('Migrating VM to hypervisor "{}"'.format(self.hypervisor), '{}:'.format(self.domuuid), 'i')
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migrate_ret = self.live_migrate_vm(self.hypervisor)
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if migrate_ret != 0:
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ansiiprint.echo('Could not live migrate VM; shutting down to migrate instead', '{}:'.format(self.domuuid), 'e')
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self.shutdown_vm()
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time.sleep(1)
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii'))
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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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time.sleep(1)
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii'))
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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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self.inreceive = True
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ansiiprint.echo('Receiving migration', '{}:'.format(self.domuuid), 'i')
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while True:
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time.sleep(0.5)
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self.state = self.zk.get('/domains/{}/state'.format(self.domuuid))[0].decode('ascii')
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self.dom = self.lookupByUUID(self.domuuid)
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if self.dom == None and self.state == 'migrate':
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continue
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if self.state != 'migrate':
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break
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try:
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if self.dom.state()[0] == libvirt.VIR_DOMAIN_RUNNING:
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break
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except:
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continue
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if self.dom.state()[0] == libvirt.VIR_DOMAIN_RUNNING:
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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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ansiiprint.echo('Successfully received migrated VM', '{}:'.format(self.domuuid), 'o')
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii'))
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else:
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ansiiprint.echo('Failed to receive migrated VM', '{}:'.format(self.domuuid), 'e')
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii'))
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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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# Give ourselves a bit of leeway time
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time.sleep(0.2)
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# Get the current values from zookeeper (don't rely on the watch)
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self.state = self.zk.get('/domains/{}/state'.format(self.domuuid))[0].decode('ascii')
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self.hypervisor = self.zk.get('/domains/{}/hypervisor'.format(self.domuuid))[0].decode('ascii')
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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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ansiiprint.echo('VM state change for "{}": {} {}'.format(self.domuuid, self.state, self.hypervisor), '', 'i')
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#######################
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# Handle state changes
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#######################
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# Valid states are:
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# start
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# migrate
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# restart
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# shutdown
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# stop
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# Conditional pass one - Are we already performing an action
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if self.instart == False \
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and self.inrestart == False \
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and self.inmigrate == False \
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and self.inreceive == False \
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and self.inshutdown == False \
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and self.instop == False:
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# Conditional pass two - Is this VM configured to run on this hypervisor
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if self.hypervisor == self.thishypervisor.name:
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# Conditional pass three - Is this VM currently running on this hypervisor
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if running == libvirt.VIR_DOMAIN_RUNNING:
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# VM is already running and should be
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if self.state == "start":
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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 is already running and should be but stuck in migrate state
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elif self.state == "migrate":
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self.zk.set('/domains/{}/state'.format(self.domuuid), '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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# VM should be restarted
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elif self.state == "restart":
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self.restart_vm()
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# VM should be shut down
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elif self.state == "shutdown":
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self.shutdown_vm()
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# VM should be stopped
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elif self.state == "stop":
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self.stop_vm()
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else:
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# VM should be started
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if self.state == "start":
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self.start_vm()
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# VM should be migrated to this hypervisor
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elif self.state == "migrate":
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self.receive_migrate()
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# VM should be restarted (i.e. started since it isn't running)
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if self.state == "restart":
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self.zk.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii'))
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# VM should be shut down; ensure it's gone from this node's domain_list
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elif self.state == "shutdown":
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if self.domuuid in self.thishypervisor.domain_list:
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self.thishypervisor.domain_list.remove(self.domuuid)
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# VM should be stoped; ensure it's gone from this node's domain_list
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elif self.state == "stop":
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if self.domuuid in self.thishypervisor.domain_list:
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self.thishypervisor.domain_list.remove(self.domuuid)
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else:
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# Conditional pass three - Is this VM currently running on this hypervisor
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if running == libvirt.VIR_DOMAIN_RUNNING:
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# VM should be migrated away from this hypervisor
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if self.state == "migrate":
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self.migrate_vm()
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# VM should be terminated
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else:
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self.terminate_vm()
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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(self, 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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ansiiprint.echo('Failed to open local libvirt connection', '{}:'.format(self.domuuid), 'e')
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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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