tests/avocado: start PhoneServer upfront

Race conditions can happen with the current code, because the port that
was available might not be anymore by the time the server is started.

By setting the port to 0, PhoneServer it will use the OS default
behavior to get a free port, then we save this information so we can
later configure the guest.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Beraldo Leal <bleal@redhat.com>
Message-Id: <20220311171127.2189534-1-bleal@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/avocado/avocado_qemu/__init__.py

@@ -18,7 +18,7 @@ import time
 import uuid
 
 import avocado
-from avocado.utils import cloudinit, datadrainer, network, process, ssh, vmimage
+from avocado.utils import cloudinit, datadrainer, process, ssh, vmimage
 from avocado.utils.path import find_command
 
 #: The QEMU build root directory.  It may also be the source directory
@@ -602,9 +602,6 @@ class LinuxTest(LinuxSSHMixIn, QemuSystemTest):
         self.log.info('Preparing cloudinit image')
         try:
             cloudinit_iso = os.path.join(self.workdir, 'cloudinit.iso')
-            self.phone_home_port = network.find_free_port()
-            if not self.phone_home_port:
-                self.cancel('Failed to get a free port')
             pubkey_content = None
             if ssh_pubkey:
                 with open(ssh_pubkey) as pubkey:
@@ -614,7 +611,7 @@ class LinuxTest(LinuxSSHMixIn, QemuSystemTest):
                           password=self.password,
                           # QEMU's hard coded usermode router address
                           phone_home_host='10.0.2.2',
-                          phone_home_port=self.phone_home_port,
+                          phone_home_port=self.phone_server.server_port,
                           authorized_key=pubkey_content)
         except Exception:
             self.cancel('Failed to prepare the cloudinit image')
@@ -625,6 +622,8 @@ class LinuxTest(LinuxSSHMixIn, QemuSystemTest):
         self.vm.add_args('-drive', 'file=%s' % path)
 
     def set_up_cloudinit(self, ssh_pubkey=None):
+        self.phone_server = cloudinit.PhoneHomeServer(('0.0.0.0', 0),
+                                                      self.name)
         cloudinit_iso = self.prepare_cloudinit(ssh_pubkey)
         self.vm.add_args('-drive', 'file=%s,format=raw' % cloudinit_iso)
 
@@ -635,7 +634,9 @@ class LinuxTest(LinuxSSHMixIn, QemuSystemTest):
                                                  logger=self.log.getChild('console'))
         console_drainer.start()
         self.log.info('VM launched, waiting for boot confirmation from guest')
-        cloudinit.wait_for_phone_home(('0.0.0.0', self.phone_home_port), self.name)
+        while not self.phone_server.instance_phoned_back:
+            self.phone_server.handle_request()
+
         if set_up_ssh_connection:
             self.log.info('Setting up the SSH connection')
             self.ssh_connect(self.username, self.ssh_key)