Start the GNS3 VM

def start(self):
        """
        Start the GNS3 VM
        """
        engine = self.current_engine()
        if not engine.running:
            if self._settings["vmname"] is None:
                return
            log.info("Start the GNS3 VM")
            engine.vmname = self._settings["vmname"]
            engine.ram = self._settings["ram"]
            engine.vcpus = self._settings["vcpus"]
            engine.headless = self._settings["headless"]
            compute = yield from self._controller.add_compute(compute_id="vm",
                                                              name="GNS3 VM is starting ({})".format(engine.vmname),
                                                              host=None,
                                                              force=True,
                                                              connect=False)

            try:
                yield from engine.start()
            except Exception as e:
                yield from self._controller.delete_compute("vm")
                log.error("Can't start the GNS3 VM: {}".format(str(e)))
                yield from compute.update(name="GNS3 VM ({})".format(engine.vmname))
                raise e
            yield from compute.connect()  # we can connect now that the VM has started
            yield from compute.update(name="GNS3 VM ({})".format(engine.vmname),
                                      protocol=self.protocol,
                                      host=self.ip_address,
                                      port=self.port,
                                      user=self.user,
                                      password=self.password)

            # check if the VM is in the same subnet as the local server, start 10 seconds later to give
            # some time for the compute in the VM to be ready for requests
            asyncio.get_event_loop().call_later(10, lambda: asyncio.async(self._check_network(compute)))