From c8d72df32a96658aaf9c601e0a9093bac090cd5e Mon Sep 17 00:00:00 2001
From: Till Maas <opensource@till.name>
Date: May 23 2018 13:11:40 +0000
Subject: [PATCH 1/2] Use random port for hostfwd


This reduces a race condition that the port allocation might fail for
qemu.

---

diff --git a/inventory/standard-inventory-qcow2 b/inventory/standard-inventory-qcow2
index 43af9a5..d15de7a 100755
--- a/inventory/standard-inventory-qcow2
+++ b/inventory/standard-inventory-qcow2
@@ -1,19 +1,20 @@
 #!/usr/bin/env python
 
 import argparse
+import distutils.util
 import errno
 import json
+import multiprocessing
 import os
-import shutil
+import random
 import shlex
+import shutil
 import signal
-import multiprocessing
 import socket
 import subprocess
 import sys
 import tempfile
 import time
-import distutils.util
 
 IDENTITY = """
 -----BEGIN RSA PRIVATE KEY-----
@@ -111,7 +112,10 @@ def inv_list(subjects):
 
 
 def start_qemu(image, cloudinit, log, portrange=(2222, 5555)):
-    for port in range(*portrange):
+
+    tries = 0
+    while tries < (portrange[1] - portrange[0]):
+        port = random.randrange(*portrange)
         sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
         try:
@@ -122,6 +126,7 @@ def start_qemu(image, cloudinit, log, portrange=(2222, 5555)):
             break
         finally:
             sock.close()
+        tries += 1
     else:
         raise RuntimeError("unable to find free local port to map SSH to")
 

From 8e70d7c2dd1ebc9729e943c17ad2416824b27ec3 Mon Sep 17 00:00:00 2001
From: Till Maas <opensource@till.name>
Date: May 23 2018 13:14:29 +0000
Subject: [PATCH 2/2] Use random vnc port


This reduces the chances of conflicts, this addresses issue #199.
However, ideally the script should retry to start qemu if a port
allocation fails instead of hoping to get a free port.

---

diff --git a/inventory/standard-inventory-qcow2 b/inventory/standard-inventory-qcow2
index d15de7a..7e94f2b 100755
--- a/inventory/standard-inventory-qcow2
+++ b/inventory/standard-inventory-qcow2
@@ -130,15 +130,20 @@ def start_qemu(image, cloudinit, log, portrange=(2222, 5555)):
     else:
         raise RuntimeError("unable to find free local port to map SSH to")
 
+    vncoffset = portrange[1] - port
     # Use -cpu host and -smp by default.
     # virtio-rng-pci: https://wiki.qemu.org/Features/VirtIORNG
-    return subprocess.Popen(["/usr/bin/qemu-system-x86_64",
-                             "-cpu", "host", "-smp", "{}".format(multiprocessing.cpu_count()),
-                             "-m", "1024", image, "-enable-kvm", "-snapshot", "-cdrom", cloudinit,
-                             "-net", "nic,model=virtio", "-net", "user,hostfwd=tcp:127.0.0.3:{0}-:22".format(port),
-                             "-device", "virtio-rng-pci", "-rtc", "base=utc",
-                             "-device", "isa-serial,chardev=pts2", "-chardev", "file,id=pts2,path=" + log,
-                             "-display", "none", "-vnc", ":1"], stdout=open(log, 'a'), stderr=subprocess.STDOUT), port
+    return subprocess.Popen(
+        ["/usr/bin/qemu-system-x86_64", "-cpu", "host",
+         "-smp", "{}".format(multiprocessing.cpu_count()),
+         "-m", "1024", image, "-enable-kvm", "-snapshot", "-cdrom", cloudinit,
+         "-net", "nic,model=virtio",
+         "-net", "user,hostfwd=tcp:127.0.0.3:{0}-:22".format(port),
+         "-device", "virtio-rng-pci", "-rtc", "base=utc",
+         "-device", "isa-serial,chardev=pts2",
+         "-chardev", "file,id=pts2,path=" + log, "-display", "none",
+         "-vnc", ":" + str(vncoffset)
+        ], stdout=open(log, 'a'), stderr=subprocess.STDOUT), port
 
 
 def inv_host(image):