ucloud-vm/virtualmachine.py
Ahmed Bilal 745d5f315a Wip
2019-09-03 18:18:43 +02:00

258 lines
8.9 KiB
Python
Executable file

# QEMU Manual
# https://qemu.weilnetz.de/doc/qemu-doc.html
# For QEMU Monitor Protocol Commands Information, See
# https://qemu.weilnetz.de/doc/qemu-doc.html#pcsys_005fmonitor
import subprocess
import traceback
import errno
import qmp
import tempfile
import bitmath
import time
from ucloud_common.vm import VMStatus, VMEntry
from config import (vm_pool, request_pool, etcd_client, logging, running_vms)
from typing import Union
from functools import wraps
from dataclasses import dataclass
from ucloud_common.request import RequestEntry, RequestType
import sshtunnel
from decouple import config
from os.path import join
from ucloud_common.helpers import get_ipv4_address
@dataclass
class VM:
key: str
handle: qmp.QEMUMachine
vnc_socket_file: tempfile.NamedTemporaryFile
def __repr__(self):
return f"VM({self.key})"
def get_start_command_args(vm_entry, vnc_sock_filename: str, migration=False, migration_port=4444):
vm_memory = int(bitmath.Byte(int(vm_entry.specs["ram"])).to_MB())
vm_cpus = int(vm_entry.specs["cpu"])
vm_uuid = vm_entry.uuid
threads_per_core = 1
command = (f"-drive file=rbd:uservms/{vm_uuid},format=raw,if=virtio,cache=none"
f" -device virtio-rng-pci -vnc unix:{vnc_sock_filename}"
f" -m {vm_memory} -smp cores={vm_cpus},threads={threads_per_core}"
f" -name {vm_uuid}")
if migration:
command += f" -incoming tcp:0:{migration_port}"
return command.split(" ")
def create_vm_object(vm_entry, migration=False, migration_port=4444):
# NOTE: If migration suddenly stop working, having different
# VNC unix filename on source and destination host can
# be a possible cause of it.
# REQUIREMENT: Use Unix Socket instead of TCP Port for VNC
vnc_sock_file = tempfile.NamedTemporaryFile()
qemu_machine = qmp.QEMUMachine("/usr/bin/qemu-system-x86_64",
args=get_start_command_args(vm_entry,
vnc_sock_file.name,
migration=migration,
migration_port=migration_port
)
)
return VM(vm_entry.key, qemu_machine, vnc_sock_file)
def get_vm(vm_list: list, vm_key) -> Union[VM, None]:
return next((vm for vm in vm_list if vm.key == vm_key), None)
def need_running_vm(func):
@wraps(func)
def wrapper(e):
vm = get_vm(running_vms, e.key)
if vm:
try:
status = vm.handle.command("query-status")
logging.debug(f"VM Status Check - {status}")
except OSError:
logging.info(
f"{func.__name__} failed - VM {e.key} - Unknown Error"
)
return func(e)
else:
logging.info(
f"{func.__name__} failed because VM {e.key} is not running"
)
return
return wrapper
def create(vm_entry: VMEntry):
vm_hdd = int(bitmath.Byte(int(vm_entry.specs["hdd"])).to_MB())
_command_to_create = f"rbd clone images/{vm_entry.image_uuid}@protected uservms/{vm_entry.uuid}"
_command_to_extend = f"rbd resize uservms/{vm_entry.uuid} --size {vm_hdd}"
try:
subprocess.check_call(_command_to_create.split(" "))
except subprocess.CalledProcessError as e:
if e.returncode == errno.EEXIST:
logging.debug(f"Image for vm {vm_entry.uuid} exists")
# File Already exists. No Problem Continue
return
else:
# This exception catches all other exceptions
# i.e FileNotFound (BaseImage), pool Does Not Exists etc.
logging.exception(f"Can't clone image - {e}")
else:
# TODO: Check whether the below suprocess.check_call
# is executed successfully
subprocess.check_call(_command_to_extend.split(" "))
logging.info("New VM Created")
def start(vm_entry: VMEntry):
_vm = get_vm(running_vms, vm_entry.key)
# VM already running. No need to proceed further.
if _vm:
logging.info(f"VM {vm_entry.uuid} already running")
return
else:
create(vm_entry)
logging.info(f"Starting {vm_entry.key}")
vm = create_vm_object(vm_entry)
try:
vm.handle.launch()
except (qmp.QEMUMachineError, TypeError, Exception):
vm_entry.declare_killed()
vm_entry.add_log(f"Machine Error occurred - {traceback.format_exc()}")
vm_pool.put(vm_entry)
else:
running_vms.append(vm)
vm_entry.status = VMStatus.running
vm_entry.add_log("Started successfully")
vm_pool.put(vm_entry)
@need_running_vm
def stop(vm_entry):
vm = get_vm(running_vms, vm_entry.key)
vm.handle.shutdown()
if not vm.handle.is_running():
vm_entry.add_log("Shutdown successfully")
vm_entry.declare_stopped()
vm_pool.put(vm_entry)
running_vms.remove(vm)
def delete(vm_entry):
logging.info(f"Deleting VM {vm_entry}")
stop(vm_entry)
path_without_protocol = vm_entry.path[vm_entry.path.find(":") + 1:]
try:
rc = subprocess.call(f"rbd rm {path_without_protocol}".split(" "))
except FileNotFoundError as e:
logging.exception(e)
except Exception as e:
logging.exception(f"Unknown error occurred - {e}")
else:
if rc == 0:
etcd_client.client.delete(vm_entry.key)
else:
logging.info("Some unknown problem occur while deleting vm file")
def transfer(request_event):
# This function would run on source host i.e host on which the vm
# is running initially. This host would be responsible for transferring
# vm state to destination host.
_host, _port = request_event.parameters["host"], request_event.parameters["port"]
_uuid = request_event.uuid
_destination = request_event.destination_host_key
vm = get_vm(running_vms, join("/v1/vm", _uuid))
if vm:
tunnel = sshtunnel.SSHTunnelForwarder(
(_host, 22),
ssh_username=config("ssh_username"),
ssh_pkey=config("ssh_pkey"),
ssh_private_key_password=config("ssh_private_key_password"),
remote_bind_address=('127.0.0.1', _port),
)
try:
tunnel.start()
except sshtunnel.BaseSSHTunnelForwarderError:
logging.exception(f"Couldn't establish connection to ({_host}, 22)")
else:
vm.handle.command("migrate", uri=f"tcp:{_host}:{tunnel.local_bind_port}")
status = vm.handle.command("query-migrate")["status"]
while status not in ["failed", "completed"]:
time.sleep(2)
status = vm.handle.command("query-migrate")["status"]
with vm_pool.get_put(request_event.uuid) as source_vm:
if status == "failed":
source_vm.add_log("Migration Failed")
elif status == "completed":
# If VM is successfully migrated then shutdown the VM
# on this host and update hostname to destination host key
source_vm.add_log("Successfully migrated")
source_vm.hostname = _destination
running_vms.remove(vm)
vm.handle.shutdown()
source_vm.in_migration = False # VM transfer finished
finally:
tunnel.close()
def init_migration(vm_entry, destination_host_key):
# This function would run on destination host i.e host on which the vm
# would be transferred after migration.
# This host would be responsible for starting VM that would receive
# state of VM running on source host.
_vm = get_vm(running_vms, vm_entry.key)
if _vm:
# VM already running. No need to proceed further.
logging.info(f"{_vm.key} Already running")
return
logging.info(f"Starting {vm_entry.key}")
vm = create_vm_object(vm_entry, migration=True, migration_port=4444)
try:
vm.handle.launch()
except Exception as e:
# We don't care whether MachineError or any other error occurred
logging.exception(e)
vm.handle.shutdown()
else:
vm_entry.in_migration = True
vm_pool.put(vm_entry)
running_vms.append(vm)
r = RequestEntry.from_scratch(type=RequestType.TransferVM,
hostname=vm_entry.hostname,
parameters={
"host": get_ipv4_address(),
"port": 4444,
},
uuid=vm_entry.uuid,
destination_host_key=destination_host_key
)
request_pool.put(r)