#!/usr/bin/env python3 # VMInstance.py - Class implementing a PVC virtual machine and run by pvcd # Part of the Parallel Virtual Cluster (PVC) system # # Copyright (C) 2018 Joshua M. Boniface # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . # ############################################################################### import os, sys, uuid, socket, time, threading, libvirt, kazoo.client import pvcd.ansiiprint as ansiiprint class VMInstance: # Initialization function def __init__(self, domuuid, zk_conn, config, thishypervisor): # Passed-in variables on creation self.domuuid = domuuid self.zk_conn = zk_conn self.config = config self.thishypervisor = thishypervisor # These will all be set later self.hypervisor = None self.state = None self.instart = False self.inrestart = False self.inmigrate = False self.inreceive = False self.inshutdown = False self.instop = False self.dom = self.lookupByUUID(self.domuuid) # Watch for changes to the state field in Zookeeper @zk_conn.DataWatch('/domains/{}/state'.format(self.domuuid)) def watch_state(data, stat, event=""): # If we get a delete state, just terminate outselves if data == None: return # Otherwise perform a management command else: self.manage_vm_state() # Get data functions def getstate(self): return self.state def gethypervisor(self): return self.hypervisor def getdom(self): return self.dom # Start up the VM def start_vm(self): ansiiprint.echo('Starting VM', '{}:'.format(self.domuuid), 'i') self.instart = True # Start up a new Libvirt connection libvirt_name = "qemu:///system" lv_conn = libvirt.open(libvirt_name) if lv_conn == None: ansiiprint.echo('Failed to open local libvirt connection', '{}:'.format(self.domuuid), 'e') self.instart = False return try: # Grab the domain information from Zookeeper xmlconfig = self.zk_conn.get('/domains/{}/xml'.format(self.domuuid))[0].decode('ascii') dom = lv_conn.createXML(xmlconfig, 0) ansiiprint.echo('Successfully started VM', '{}:'.format(self.domuuid), 'o') self.dom = dom except libvirt.libvirtError as e: ansiiprint.echo('Failed to create VM', '{}:'.format(self.domuuid), 'e') self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'failed'.encode('ascii')) self.dom = None lv_conn.close() self.instart = False # Restart the VM def restart_vm(self): ansiiprint.echo('Restarting VM', '{}:'.format(self.domuuid), 'i') self.inrestart = True # Start up a new Libvirt connection libvirt_name = "qemu:///system" lv_conn = libvirt.open(libvirt_name) if lv_conn == None: ansiiprint.echo('Failed to open local libvirt connection', '{}:'.format(self.domuuid), 'e') self.inrestart = False return try: self.shutdown_vm() self.start_vm() ansiiprint.echo('Successfully restarted VM', '{}:'.format(self.domuuid), 'o') except libvirt.libvirtError as e: ansiiprint.echo('Failed to restart VM', '{}:'.format(self.domuuid), 'e') self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii')) lv_conn.close() self.inrestart = False # Stop the VM forcibly without updating state def terminate_vm(self): ansiiprint.echo('Terminating VM', '{}:'.format(self.domuuid), 'i') self.instop = True try: self.dom.destroy() except AttributeError: ansiiprint.echo('Failed to terminate VM', '{}:'.format(self.domuuid), 'e') ansiiprint.echo('Successfully terminated VM', '{}:'.format(self.domuuid), 'o') self.dom = None self.instop = False # Stop the VM forcibly def stop_vm(self): ansiiprint.echo('Forcibly stopping VM', '{}:'.format(self.domuuid), 'i') self.instop = True try: self.dom.destroy() except AttributeError: ansiiprint.echo('Failed to stop VM', '{}:'.format(self.domuuid), 'e') if self.inrestart == False: self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'stop'.encode('ascii')) ansiiprint.echo('Successfully stopped VM', '{}:'.format(self.domuuid), 'o') self.dom = None self.instop = False # Shutdown the VM gracefully def shutdown_vm(self): ansiiprint.echo('Gracefully stopping VM', '{}:'.format(self.domuuid), 'i') self.inshutdown = True self.dom.shutdown() try: tick = 0 while self.dom.state()[0] == libvirt.VIR_DOMAIN_RUNNING and tick < 60: tick += 1 time.sleep(0.5) if tick >= 60: ansiiprint.echo('Shutdown timeout expired', '{}:'.format(self.domuuid), 'e') self.stop_vm() self.inshutdown = False return except: pass if self.inrestart == False: self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'stop'.encode('ascii')) ansiiprint.echo('Successfully shutdown VM', '{}:'.format(self.domuuid), 'o') self.dom = None self.inshutdown = False def live_migrate_vm(self, dest_hypervisor): try: dest_lv_conn = libvirt.open('qemu+tcp://{}/system'.format(self.hypervisor)) if dest_lv_conn == None: raise except: ansiiprint.echo('Failed to open connection to qemu+tcp://{}/system; aborting migration.'.format(self.hypervisor), '{}:'.format(self.domuuid), 'e') return 1 try: target_dom = self.dom.migrate(dest_lv_conn, libvirt.VIR_MIGRATE_LIVE, None, None, 0) if target_dom == None: raise ansiiprint.echo('Successfully migrated VM', '{}:'.format(self.domuuid), 'o') except: dest_lv_conn.close() return 1 dest_lv_conn.close() return 0 # Migrate the VM to a target host def migrate_vm(self): self.inmigrate = True ansiiprint.echo('Migrating VM to hypervisor "{}"'.format(self.hypervisor), '{}:'.format(self.domuuid), 'i') migrate_ret = self.live_migrate_vm(self.hypervisor) if migrate_ret != 0: ansiiprint.echo('Could not live migrate VM; shutting down to migrate instead', '{}:'.format(self.domuuid), 'e') self.shutdown_vm() time.sleep(1) self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii')) self.inmigrate = False # Receive the migration from another host (wait until VM is running) def receive_migrate(self): self.inreceive = True ansiiprint.echo('Receiving migration', '{}:'.format(self.domuuid), 'i') while True: time.sleep(0.5) self.state = self.zk_conn.get('/domains/{}/state'.format(self.domuuid))[0].decode('ascii') self.dom = self.lookupByUUID(self.domuuid) if self.dom == None and self.state == 'migrate': continue if self.state != 'migrate': break try: if self.dom.state()[0] == libvirt.VIR_DOMAIN_RUNNING: break except: continue try: dom_state = self.dom.state()[0] except AttributeError: dom_state = None if dom_state == libvirt.VIR_DOMAIN_RUNNING: ansiiprint.echo('Successfully received migrated VM', '{}:'.format(self.domuuid), 'o') else: ansiiprint.echo('Failed to receive migrated VM', '{}:'.format(self.domuuid), 'e') self.inreceive = False # # Main function to manage a VM (taking only self) # def manage_vm_state(self): # Give ourselves a bit of leeway time time.sleep(0.2) # Get the current values from zookeeper (don't rely on the watch) self.state = self.zk_conn.get('/domains/{}/state'.format(self.domuuid))[0].decode('ascii') self.hypervisor = self.zk_conn.get('/domains/{}/hypervisor'.format(self.domuuid))[0].decode('ascii') # Check the current state of the VM try: if self.dom != None: running, reason = self.dom.state() else: raise except: running = libvirt.VIR_DOMAIN_NOSTATE ansiiprint.echo('VM state change for "{}": {} {}'.format(self.domuuid, self.state, self.hypervisor), '', 'i') ####################### # Handle state changes ####################### # Valid states are: # start # migrate # restart # shutdown # stop # Conditional pass one - Are we already performing an action if self.instart == False \ and self.inrestart == False \ and self.inmigrate == False \ and self.inreceive == False \ and self.inshutdown == False \ and self.instop == False: # Conditional pass two - Is this VM configured to run on this hypervisor if self.hypervisor == self.thishypervisor.name: # Conditional pass three - Is this VM currently running on this hypervisor if running == libvirt.VIR_DOMAIN_RUNNING: # VM is already running and should be if self.state == "start": pass # VM is already running and should be but stuck in migrate state elif self.state == "migrate": self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii')) # VM should be restarted elif self.state == "restart": self.restart_vm() # VM should be shut down elif self.state == "shutdown": self.shutdown_vm() # VM should be stopped elif self.state == "stop": self.stop_vm() else: # VM should be started if self.state == "start": self.start_vm() # VM should be migrated to this hypervisor elif self.state == "migrate": self.receive_migrate() # VM should be restarted (i.e. started since it isn't running) if self.state == "restart": self.zk_conn.set('/domains/{}/state'.format(self.domuuid), 'start'.encode('ascii')) # VM should be shut down elif self.state == "shutdown": pass # VM should be stoped elif self.state == "stop": pass else: # Conditional pass three - Is this VM currently running on this hypervisor if running == libvirt.VIR_DOMAIN_RUNNING: # VM should be migrated away from this hypervisor if self.state == "migrate": self.migrate_vm() # VM should be terminated else: self.terminate_vm() # This function is a wrapper for libvirt.lookupByUUID which fixes some problems # 1. Takes a text UUID and handles converting it to bytes # 2. Try's it and returns a sensible value if not def lookupByUUID(self, tuuid): lv_conn = None dom = None libvirt_name = "qemu:///system" # Convert the text UUID to bytes buuid = uuid.UUID(tuuid).bytes # Try try: # Open a libvirt connection lv_conn = libvirt.open(libvirt_name) if lv_conn == None: ansiiprint.echo('Failed to open local libvirt connection', '{}:'.format(self.domuuid), 'e') return dom # Lookup the UUID dom = lv_conn.lookupByUUID(buuid) # Fail except: pass # After everything finally: # Close the libvirt connection if lv_conn != None: lv_conn.close() # Return the dom object (or None) return dom