launchers/kvm : utilisation de variables d'environnement pour setup la VM

qemu/launchers/kvm

@@ -1,20 +1,35 @@
 #!/usr/bin/env python3
-from os import execvp
+from os import environ
+
+# Set number of vCPUs to use to the environment variable QEMUSH_NPROC or
+# half of total vCPUs installed if it fails
+try:
+    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
-
-nproc = cpu_count() // 2
-ram_kilo = virtual_memory().available // 2 // 1024
-
 command = [
     'qemu-system-x86_64',
     '-enable-kvm', '-daemonize',
     '-M', 'q35',
-    '-cpu', 'host', '-smp', str(nproc),
-    '-m', '{}K'.format(ram_kilo),
+    '-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)