134 lines
5.1 KiB
Python
134 lines
5.1 KiB
Python
#!/usr/bin/env python3
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import os, time, uuid, 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.dom = None
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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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if self.hypervisor != data.decode('ascii'):
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self.hypervisor = data.decode('ascii')
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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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if self.state != data.decode('ascii'):
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self.state = data.decode('ascii')
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self.manage_vm_state()
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# Start up the VM
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def start_vm(self, conn, xmlconfig):
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print("Starting VM %s" % self.domuuid)
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try:
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dom = conn.createXML(xmlconfig, 0)
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except:
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print('Failed to create domain %s' % self.domuuid)
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self.zk.set(self.zkey + '/state', 'stop'.encode('ascii'))
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return None
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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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return dom
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# Stop the VM forcibly
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def stop_vm(self):
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print("Forcibly stopping VM %s" % self.domuuid)
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self.dom.destroy()
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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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# Shutdown the VM gracefully
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def shutdown_vm(self):
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print("Stopping VM %s" % self.domuuid)
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self.dom.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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# Migrate the VM to a target host
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def migrate_vm(self):
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self.zk.set(self.zkey + '/status', b'migrate')
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dest_conn = libvirt.open('qemu+ssh://%s/system' % target)
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if dest_conn == None:
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print('Failed to open connection to qemu+ssh://%s/system' % target)
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exit(1)
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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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print('Could not migrate to the new domain')
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exit(1)
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self.thishypervisor.domain_list.remove(self.domuuid)
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print('Migrated successfully')
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dest_conn.close()
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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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while True:
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if self.dom.state() != libvirt.VIR_DOMAIN_RUNNING:
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continue
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else:
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self.zk.set(self.zkey + '/status', b'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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break
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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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# 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('Failed to open local libvirt connection.')
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exit(1)
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# Check the current state of the VM
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try:
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self.dom = conn.lookupByUUID(uuid.UUID(self.domuuid).bytes)
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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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running = libvirt.VIR_DOMAIN_NOSTATE
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except:
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running = libvirt.VIR_DOMAIN_NOSTATE
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if running == libvirt.VIR_DOMAIN_RUNNING and self.state == "stop" and self.hypervisor == self.thishypervisor.name:
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self.stop_vm()
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if running == libvirt.VIR_DOMAIN_RUNNING and self.state == "shutdown" and self.hypervisor == self.thishypervisor.name:
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self.shutdown_vm()
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elif running != libvirt.VIR_DOMAIN_RUNNING and self.state == "migrate" and self.hypervisr == self.thishypervisor.name:
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self.receive_migrate()
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elif running == libvirt.VIR_DOMAIN_RUNNING and self.state == "migrate" and self.hypervisr != self.thishypervisor.name:
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self.migrate_vm()
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elif running != libvirt.VIR_DOMAIN_RUNNING and self.state == "start" and self.hypervisor == self.thishypervisor.name:
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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.dom = self.start_vm(conn, domxml)
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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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# The VM should now be running so return the domain and active connection
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conn.close
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