qemush/qemu/launchers/kvm

#!/usr/bin/env python3

# Retrieve the name of the monitor socket
from subprocess import CalledProcessError
try:
    from subprocess import check_output
    socket = 'unix:%s,server,nowait' % (check_output(["sockpath"], text=True))
except CalledProcessError as e:
    exit(e.returncode)

# Set number of vCPUs to use to the environment variable QEMUSH_NPROC or
# half of total vCPUs installed if it fails
try:
    from os import environ
    nproc = environ['QEMUSH_NPROC']
except KeyError:
    from multiprocessing import cpu_count
    nproc = str(cpu_count() // 2)

# Set amount of RAM to use to the environment variable QEMUSH_RAM or half
# of total RAM installed if it fails
try:
    ram = environ['QEMUSH_RAM']
except KeyError:
    from psutil import virtual_memory
    ram = str(virtual_memory().available // 2 // (1024 ** 2))

# Set the command to initialize; all required parameters to make a sane KVM
# are included and optional arguments are appended from argv
from sys import argv
command = [
    'qemu-system-x86_64',
    '-enable-kvm', '-daemonize',
    '-monitor', socket,
    '-M', 'q35',
    '-cpu', 'host', '-smp', nproc,
    '-m', ram,
    '-net', 'nic'
] + argv[1:]

# Print the final command and replace the main process with it
print(command)
from os import execvp
execvp(command[0], command)