예제 #1
0
파일: qemu.py 프로젝트: tjamrisk/virt-test
    def __init__(self, test, params, env, preprocess_env=True):
        self.test = test
        self.params = params
        self.env = env
        self.hosts = params.get("hosts")
        self.hostid = params.get("hostid", "")
        self.comm_port = int(params.get("comm_port", 13234))
        vms_count = len(params["vms"].split())

        self.login_timeout = int(params.get("login_timeout", 360))
        self.disk_prepare_timeout = int(params.get("disk_prepare_timeout", 160 * vms_count))
        self.finish_timeout = int(params.get("finish_timeout", 120 * vms_count))

        self.new_params = None

        if params.get("clone_master") == "yes":
            self.clone_master = True
        else:
            self.clone_master = False

        self.mig_timeout = int(params.get("mig_timeout"))
        # Port used to communicate info between source and destination
        self.regain_ip_cmd = params.get("regain_ip_cmd", None)
        self.not_login_after_mig = params.get("not_login_after_mig", None)

        self.vm_lock = threading.Lock()

        self.sync_server = None
        if self.clone_master:
            self.sync_server = SyncListenServer()

        if preprocess_env:
            self.preprocess_env()
            self._hosts_barrier(self.hosts, self.hosts, "disk_prepared", self.disk_prepare_timeout)
예제 #2
0
    def __init__(self, test, params, env, preprocess_env=True):
        self.test = test
        self.params = params
        self.env = env
        self.hosts = params.get("hosts")
        self.hostid = params.get('hostid', "")
        self.comm_port = int(params.get("comm_port", 13234))
        vms_count = len(params["vms"].split())

        self.login_timeout = int(params.get("login_timeout", 360))
        self.disk_prepare_timeout = int(params.get("disk_prepare_timeout",
                                                   160 * vms_count))
        self.finish_timeout = int(params.get("finish_timeout",
                                             120 * vms_count))

        self.new_params = None

        if params.get("clone_master") == "yes":
            self.clone_master = True
        else:
            self.clone_master = False

        self.mig_protocol = params.get("mig_protocol", "tcp")
        self.mig_timeout = int(params.get("mig_timeout"))
        # Port used to communicate info between source and destination
        self.regain_ip_cmd = params.get("regain_ip_cmd", None)
        self.not_login_after_mig = params.get("not_login_after_mig", None)

        self.vm_lock = threading.Lock()

        self.sync_server = None
        if self.clone_master:
            self.sync_server = SyncListenServer()

        if preprocess_env:
            self.preprocess_env()
            self._hosts_barrier(self.hosts, self.hosts, 'disk_prepared',
                                self.disk_prepare_timeout)
예제 #3
0
파일: qemu.py 프로젝트: aginies/virt-test
class MultihostMigration(object):

    """
    Class that provides a framework for multi-host migration.

    Migration can be run both synchronously and asynchronously.
    To specify what is going to happen during the multi-host
    migration, it is necessary to reimplement the method
    migration_scenario. It is possible to start multiple migrations
    in separate threads, since self.migrate is thread safe.

    Only one test using multihost migration framework should be
    started on one machine otherwise it is necessary to solve the
    problem with listen server port.

    Multihost migration starts SyncListenServer through which
    all messages are transferred, since the multiple hosts can
    be in different states.

    Class SyncData is used to transfer data over network or
    synchronize the migration process. Synchronization sessions
    are recognized by session_id.

    It is important to note that, in order to have multi-host
    migration, one needs shared guest image storage. The simplest
    case is when the guest images are on an NFS server.

    Example:
        class TestMultihostMigration(utils_misc.MultihostMigration):
            def __init__(self, test, params, env):
                super(testMultihostMigration, self).__init__(test, params, env)

            def migration_scenario(self):
                srchost = self.params.get("hosts")[0]
                dsthost = self.params.get("hosts")[1]

                def worker(mig_data):
                    vm = env.get_vm("vm1")
                    session = vm.wait_for_login(timeout=self.login_timeout)
                    session.sendline("nohup dd if=/dev/zero of=/dev/null &")
                    session.cmd("killall -0 dd")

                def check_worker(mig_data):
                    vm = env.get_vm("vm1")
                    session = vm.wait_for_login(timeout=self.login_timeout)
                    session.cmd("killall -9 dd")

                # Almost synchronized migration, waiting to end it.
                # Work is started only on first VM.
                self.migrate_wait(["vm1", "vm2"], srchost, dsthost,
                                  worker, check_worker)

                # Migration started in different threads.
                # It allows to start multiple migrations simultaneously.
                mig1 = self.migrate(["vm1"], srchost, dsthost,
                                    worker, check_worker)
                mig2 = self.migrate(["vm2"], srchost, dsthost)
                mig2.join()
                mig1.join()

    mig = TestMultihostMigration(test, params, env)
    mig.run()
    """

    def __init__(self, test, params, env, preprocess_env=True):
        self.test = test
        self.params = params
        self.env = env
        self.hosts = params.get("hosts")
        self.hostid = params.get('hostid', "")
        self.comm_port = int(params.get("comm_port", 13234))
        vms_count = len(params["vms"].split())

        self.login_timeout = int(params.get("login_timeout", 360))
        self.disk_prepare_timeout = int(params.get("disk_prepare_timeout",
                                                   160 * vms_count))
        self.finish_timeout = int(params.get("finish_timeout",
                                             120 * vms_count))

        self.new_params = None

        if params.get("clone_master") == "yes":
            self.clone_master = True
        else:
            self.clone_master = False

        self.mig_timeout = int(params.get("mig_timeout"))
        # Port used to communicate info between source and destination
        self.regain_ip_cmd = params.get("regain_ip_cmd", None)
        self.not_login_after_mig = params.get("not_login_after_mig", None)

        self.vm_lock = threading.Lock()

        self.sync_server = None
        if self.clone_master:
            self.sync_server = SyncListenServer()

        if preprocess_env:
            self.preprocess_env()
            self._hosts_barrier(self.hosts, self.hosts, 'disk_prepared',
                                self.disk_prepare_timeout)

    def migration_scenario(self):
        """
        Multi Host migration_scenario is started from method run where the
        exceptions are checked. It is not necessary to take care of
        cleaning up after test crash or finish.
        """
        raise NotImplementedError

    def post_migration(self, vm, cancel_delay, mig_offline, dsthost, vm_ports,
                       not_wait_for_migration, fd, mig_data):
        pass

    def migrate_vms_src(self, mig_data):
        """
        Migrate vms source.

        :param mig_Data: Data for migration.

        For change way how machine migrates is necessary
        re implement this method.
        """
        def mig_wrapper(vm, cancel_delay, dsthost, vm_ports,
                        not_wait_for_migration, mig_offline, mig_data):
            vm.migrate(cancel_delay=cancel_delay, offline=mig_offline,
                       dest_host=dsthost, remote_port=vm_ports[vm.name],
                       not_wait_for_migration=not_wait_for_migration)

            self.post_migration(vm, cancel_delay, mig_offline, dsthost,
                                vm_ports, not_wait_for_migration, None,
                                mig_data)

        logging.info("Start migrating now...")
        cancel_delay = mig_data.params.get("cancel_delay")
        if cancel_delay is not None:
            cancel_delay = int(cancel_delay)
        not_wait_for_migration = mig_data.params.get("not_wait_for_migration")
        if not_wait_for_migration == "yes":
            not_wait_for_migration = True
        mig_offline = mig_data.params.get("mig_offline")
        if mig_offline == "yes":
            mig_offline = True
        else:
            mig_offline = False

        multi_mig = []
        for vm in mig_data.vms:
            multi_mig.append((mig_wrapper, (vm, cancel_delay, mig_data.dst,
                                            mig_data.vm_ports,
                                            not_wait_for_migration,
                                            mig_offline, mig_data)))
        utils_misc.parallel(multi_mig)

    def migrate_vms_dest(self, mig_data):
        """
        Migrate vms destination. This function is started on dest host during
        migration.

        :param mig_Data: Data for migration.
        """
        pass

    def __del__(self):
        if self.sync_server:
            self.sync_server.close()

    def master_id(self):
        return self.hosts[0]

    def _hosts_barrier(self, hosts, session_id, tag, timeout):
        logging.debug("Barrier timeout: %d tags: %s" % (timeout, tag))
        tags = SyncData(self.master_id(), self.hostid, hosts,
                        "%s,%s,barrier" % (str(session_id), tag),
                        self.sync_server).sync(tag, timeout)
        logging.debug("Barrier tag %s" % (tags))

    def preprocess_env(self):
        """
        Prepare env to start vms.
        """
        storage.preprocess_images(self.test.bindir, self.params, self.env)

    def _check_vms_source(self, mig_data):
        start_mig_tout = mig_data.params.get("start_migration_timeout", None)
        if start_mig_tout is None:
            for vm in mig_data.vms:
                vm.wait_for_login(timeout=self.login_timeout)

        if mig_data.params.get("host_mig_offline") != "yes":
            sync = SyncData(self.master_id(), self.hostid, mig_data.hosts,
                            mig_data.mig_id, self.sync_server)
            mig_data.vm_ports = sync.sync(timeout=240)[mig_data.dst]
            logging.info("Received from destination the migration port %s",
                         str(mig_data.vm_ports))

    def _check_vms_dest(self, mig_data):
        mig_data.vm_ports = {}
        for vm in mig_data.vms:
            logging.info("Communicating to source migration port %s",
                         vm.migration_port)
            mig_data.vm_ports[vm.name] = vm.migration_port

        if mig_data.params.get("host_mig_offline") != "yes":
            SyncData(self.master_id(), self.hostid,
                     mig_data.hosts, mig_data.mig_id,
                     self.sync_server).sync(mig_data.vm_ports, timeout=240)

    def _prepare_params(self, mig_data):
        """
        Prepare separate params for vm migration.

        :param vms_name: List of vms.
        """
        new_params = mig_data.params.copy()
        new_params["vms"] = " ".join(mig_data.vms_name)
        return new_params

    def _check_vms(self, mig_data):
        """
        Check if vms are started correctly.

        :param vms: list of vms.
        :param source: Must be True if is source machine.
        """
        if mig_data.is_src():
            self._check_vms_source(mig_data)
        else:
            self._check_vms_dest(mig_data)

    def _quick_check_vms(self, mig_data):
        """
        Check if vms are started correctly.

        :param vms: list of vms.
        :param source: Must be True if is source machine.
        """
        logging.info("Try check vms %s" % (mig_data.vms_name))
        for vm in mig_data.vms_name:
            if not self.env.get_vm(vm) in mig_data.vms:
                mig_data.vms.append(self.env.get_vm(vm))
        for vm in mig_data.vms:
            logging.info("Check vm %s on host %s" % (vm.name, self.hostid))
            vm.verify_alive()

    def prepare_for_migration(self, mig_data, migration_mode):
        """
        Prepare destination of migration for migration.

        :param mig_data: Class with data necessary for migration.
        :param migration_mode: Migration mode for prepare machine.
        """
        new_params = self._prepare_params(mig_data)

        new_params['migration_mode'] = migration_mode
        new_params['start_vm'] = 'yes'

        if self.params.get("migration_sync_vms", "no") == "yes":
            if mig_data.is_src():
                self.vm_lock.acquire()
                env_process.process(self.test, new_params, self.env,
                                    env_process.preprocess_image,
                                    env_process.preprocess_vm)
                self.vm_lock.release()
                self._quick_check_vms(mig_data)

                # Send vms configuration to dst host.
                vms = cPickle.dumps([self.env.get_vm(vm_name)
                                     for vm_name in mig_data.vms_name])

                self.env.get_vm(mig_data.vms_name[0]).monitor.info("qtree")
                SyncData(self.master_id(), self.hostid,
                         mig_data.hosts, mig_data.mig_id,
                         self.sync_server).sync(vms, timeout=240)
            elif mig_data.is_dst():
                # Load vms configuration from src host.
                vms = cPickle.loads(SyncData(self.master_id(), self.hostid,
                                             mig_data.hosts, mig_data.mig_id,
                                             self.sync_server).sync(timeout=240)[mig_data.src])
                for vm in vms:
                    # Save config to env. Used for create machine.
                    # When reuse_previous_config params is set don't check
                    # machine.
                    vm.address_cache = self.env.get("address_cache")
                    self.env.register_vm(vm.name, vm)

                self.vm_lock.acquire()
                env_process.process(self.test, new_params, self.env,
                                    env_process.preprocess_image,
                                    env_process.preprocess_vm)
                vms[0].monitor.info("qtree")
                self.vm_lock.release()
                self._quick_check_vms(mig_data)
        else:
            self.vm_lock.acquire()
            env_process.process(self.test, new_params, self.env,
                                env_process.preprocess_image,
                                env_process.preprocess_vm)
            self.vm_lock.release()
            self._quick_check_vms(mig_data)

        self._check_vms(mig_data)

    def migrate_vms(self, mig_data):
        """
        Migrate vms.
        """
        if mig_data.is_src():
            self.migrate_vms_src(mig_data)
        else:
            self.migrate_vms_dest(mig_data)

    def check_vms_dst(self, mig_data):
        """
        Check vms after migrate.

        :param mig_data: object with migration data.
        """
        for vm in mig_data.vms:
            vm.resume()
            if not guest_active(vm):
                raise error.TestFail("Guest not active after migration")

        logging.info("Migrated guest appears to be running")

        logging.info("Logging into migrated guest after migration...")
        for vm in mig_data.vms:
            if not self.regain_ip_cmd is None:
                session_serial = vm.wait_for_serial_login(timeout=
                                                          self.login_timeout)
                # There is sometime happen that system sends some message on
                # serial console and IP renew command block test. Because
                # there must be added "sleep" in IP renew command.
                session_serial.cmd(self.regain_ip_cmd)

            if not self.not_login_after_mig:
                vm.wait_for_login(timeout=self.login_timeout)

    def check_vms_src(self, mig_data):
        """
        Check vms after migrate.

        :param mig_data: object with migration data.
        """
        pass

    def postprocess_env(self):
        """
        Kill vms and delete cloned images.
        """
        pass

    def before_migration(self, mig_data):
        """
        Do something right before migration.

        :param mig_data: object with migration data.
        """
        pass

    def migrate(self, vms_name, srchost, dsthost, start_work=None,
                check_work=None, mig_mode="tcp", params_append=None):
        """
        Migrate machine from srchost to dsthost. It executes start_work on
        source machine before migration and executes check_work on dsthost
        after migration.

        Migration execution progress:

        source host                   |   dest host
        --------------------------------------------------------
           prepare guest on both sides of migration
            - start machine and check if machine works
            - synchronize transfer data needed for migration
        --------------------------------------------------------
        start work on source guests   |   wait for migration
        --------------------------------------------------------
                     migrate guest to dest host.
              wait on finish migration synchronization
        --------------------------------------------------------
                                      |   check work on vms
        --------------------------------------------------------
                    wait for sync on finish migration

        :param vms_name: List of vms.
        :param srchost: src host id.
        :param dsthost: dst host id.
        :param start_work: Function started before migration.
        :param check_work: Function started after migration.
        :param mig_mode: Migration mode.
        :param params_append: Append params to self.params only for migration.
        """
        def migrate_wrap(vms_name, srchost, dsthost, start_work=None,
                         check_work=None, params_append=None):
            logging.info("Starting migrate vms %s from host %s to %s" %
                         (vms_name, srchost, dsthost))
            pause = self.params.get("paused_after_start_vm")
            mig_error = None
            mig_data = MigrationData(self.params, srchost, dsthost,
                                     vms_name, params_append)
            cancel_delay = self.params.get("cancel_delay", None)
            host_offline_migration = self.params.get("host_mig_offline")

            try:
                try:
                    if mig_data.is_src():
                        self.prepare_for_migration(mig_data, None)
                    elif self.hostid == dsthost:
                        if host_offline_migration != "yes":
                            self.prepare_for_migration(mig_data, mig_mode)
                    else:
                        return

                    if mig_data.is_src():
                        if start_work:
                            if pause != "yes":
                                start_work(mig_data)
                            else:
                                raise error.TestNAError("Can't start work if "
                                                        "vm is paused.")

                    # Starts VM and waits timeout before migration.
                    if pause == "yes" and mig_data.is_src():
                        for vm in mig_data.vms:
                            vm.resume()
                        wait = self.params.get("start_migration_timeout", 0)
                        logging.debug("Wait for migraiton %s seconds." %
                                      (wait))
                        time.sleep(int(wait))

                    self.before_migration(mig_data)

                    self.migrate_vms(mig_data)

                    timeout = 60
                    if cancel_delay is None:
                        if host_offline_migration == "yes":
                            self._hosts_barrier(self.hosts,
                                                mig_data.mig_id,
                                                'wait_for_offline_mig',
                                                self.finish_timeout)
                            if mig_data.is_dst():
                                self.prepare_for_migration(mig_data, mig_mode)
                            self._hosts_barrier(self.hosts,
                                                mig_data.mig_id,
                                                'wait2_for_offline_mig',
                                                self.finish_timeout)

                        if (not mig_data.is_src()):
                            timeout = self.mig_timeout
                        self._hosts_barrier(mig_data.hosts, mig_data.mig_id,
                                            'mig_finished', timeout)

                        if mig_data.is_dst():
                            self.check_vms_dst(mig_data)
                            if check_work:
                                check_work(mig_data)
                        else:
                            self.check_vms_src(mig_data)
                            if check_work:
                                check_work(mig_data)
                except:
                    mig_error = True
                    raise
            finally:
                if not mig_error and cancel_delay is None:
                    self._hosts_barrier(self.hosts,
                                        mig_data.mig_id,
                                        'test_finihed',
                                        self.finish_timeout)
                elif mig_error:
                    raise

        def wait_wrap(vms_name, srchost, dsthost):
            mig_data = MigrationData(self.params, srchost, dsthost, vms_name,
                                     None)
            timeout = (self.login_timeout + self.mig_timeout +
                       self.finish_timeout)

            self._hosts_barrier(self.hosts, mig_data.mig_id,
                                'test_finihed', timeout)

        if (self.hostid in [srchost, dsthost]):
            mig_thread = utils.InterruptedThread(migrate_wrap, (vms_name,
                                                                srchost,
                                                                dsthost,
                                                                start_work,
                                                                check_work,
                                                                params_append))
        else:
            mig_thread = utils.InterruptedThread(wait_wrap, (vms_name,
                                                             srchost,
                                                             dsthost))
        mig_thread.start()
        return mig_thread

    def migrate_wait(self, vms_name, srchost, dsthost, start_work=None,
                     check_work=None, mig_mode="tcp", params_append=None):
        """
        Migrate machine from srchost to dsthost and wait for finish.
        It executes start_work on source machine before migration and executes
        check_work on dsthost after migration.

        :param vms_name: List of vms.
        :param srchost: src host id.
        :param dsthost: dst host id.
        :param start_work: Function which is started before migration.
        :param check_work: Function which is started after
                           done of migration.
        """
        self.migrate(vms_name, srchost, dsthost, start_work, check_work,
                     mig_mode, params_append).join()

    def cleanup(self):
        """
        Cleanup env after test.
        """
        if self.clone_master:
            self.sync_server.close()
            self.postprocess_env()

    def run(self):
        """
        Start multihost migration scenario.
        After scenario is finished or if scenario crashed it calls postprocess
        machines and cleanup env.
        """
        try:
            self.migration_scenario()

            self._hosts_barrier(self.hosts, self.hosts, 'all_test_finihed',
                                self.finish_timeout)
        finally:
            self.cleanup()
예제 #4
0
class MultihostMigration(object):

    """
    Class that provides a framework for multi-host migration.

    Migration can be run both synchronously and asynchronously.
    To specify what is going to happen during the multi-host
    migration, it is necessary to reimplement the method
    migration_scenario. It is possible to start multiple migrations
    in separate threads, since self.migrate is thread safe.

    Only one test using multihost migration framework should be
    started on one machine otherwise it is necessary to solve the
    problem with listen server port.

    Multihost migration starts SyncListenServer through which
    all messages are transferred, since the multiple hosts can
    be in different states.

    Class SyncData is used to transfer data over network or
    synchronize the migration process. Synchronization sessions
    are recognized by session_id.

    It is important to note that, in order to have multi-host
    migration, one needs shared guest image storage. The simplest
    case is when the guest images are on an NFS server.

    Example:

    ::

        class TestMultihostMigration(utils_misc.MultihostMigration):
            def __init__(self, test, params, env):
                super(testMultihostMigration, self).__init__(test, params, env)

            def migration_scenario(self):
                srchost = self.params.get("hosts")[0]
                dsthost = self.params.get("hosts")[1]

                def worker(mig_data):
                    vm = env.get_vm("vm1")
                    session = vm.wait_for_login(timeout=self.login_timeout)
                    session.sendline("nohup dd if=/dev/zero of=/dev/null &")
                    session.cmd("killall -0 dd")

                def check_worker(mig_data):
                    vm = env.get_vm("vm1")
                    session = vm.wait_for_login(timeout=self.login_timeout)
                    session.cmd("killall -9 dd")

                # Almost synchronized migration, waiting to end it.
                # Work is started only on first VM.
                self.migrate_wait(["vm1", "vm2"], srchost, dsthost,
                                  worker, check_worker)

                # Migration started in different threads.
                # It allows to start multiple migrations simultaneously.
                mig1 = self.migrate(["vm1"], srchost, dsthost,
                                    worker, check_worker)
                mig2 = self.migrate(["vm2"], srchost, dsthost)
                mig2.join()
                mig1.join()

        mig = TestMultihostMigration(test, params, env)
        mig.run()
    """

    def __init__(self, test, params, env, preprocess_env=True):
        self.test = test
        self.params = params
        self.env = env
        self.hosts = params.get("hosts")
        self.hostid = params.get('hostid', "")
        self.comm_port = int(params.get("comm_port", 13234))
        vms_count = len(params["vms"].split())

        self.login_timeout = int(params.get("login_timeout", 360))
        self.disk_prepare_timeout = int(params.get("disk_prepare_timeout",
                                                   160 * vms_count))
        self.finish_timeout = int(params.get("finish_timeout",
                                             120 * vms_count))

        self.new_params = None

        if params.get("clone_master") == "yes":
            self.clone_master = True
        else:
            self.clone_master = False

        self.mig_protocol = params.get("mig_protocol", "tcp")
        self.mig_timeout = int(params.get("mig_timeout"))
        # Port used to communicate info between source and destination
        self.regain_ip_cmd = params.get("regain_ip_cmd", None)
        self.not_login_after_mig = params.get("not_login_after_mig", None)

        self.vm_lock = threading.Lock()

        self.sync_server = None
        if self.clone_master:
            self.sync_server = SyncListenServer()

        if preprocess_env:
            self.preprocess_env()
            self._hosts_barrier(self.hosts, self.hosts, 'disk_prepared',
                                self.disk_prepare_timeout)

    def migration_scenario(self):
        """
        Multi Host migration_scenario is started from method run where the
        exceptions are checked. It is not necessary to take care of
        cleaning up after test crash or finish.
        """
        raise NotImplementedError

    def post_migration(self, vm, cancel_delay, mig_offline, dsthost, vm_ports,
                       not_wait_for_migration, fd, mig_data):
        pass

    def migrate_vms_src(self, mig_data):
        """
        Migrate vms source.

        :param mig_Data: Data for migration.

        For change way how machine migrates is necessary
        re implement this method.
        """
        def mig_wrapper(vm, cancel_delay, dsthost, vm_ports,
                        not_wait_for_migration, mig_offline, mig_data):
            vm.migrate(protocol=self.mig_protocol, cancel_delay=cancel_delay,
                       offline=mig_offline,
                       dest_host=dsthost, remote_port=vm_ports[vm.name],
                       not_wait_for_migration=not_wait_for_migration)

            self.post_migration(vm, cancel_delay, mig_offline, dsthost,
                                vm_ports, not_wait_for_migration, None,
                                mig_data)

        logging.info("Start migrating now...")
        cancel_delay = mig_data.params.get("cancel_delay")
        if cancel_delay is not None:
            cancel_delay = int(cancel_delay)
        not_wait_for_migration = mig_data.params.get("not_wait_for_migration")
        if not_wait_for_migration == "yes":
            not_wait_for_migration = True
        mig_offline = mig_data.params.get("mig_offline")
        if mig_offline == "yes":
            mig_offline = True
        else:
            mig_offline = False

        multi_mig = []
        for vm in mig_data.vms:
            multi_mig.append((mig_wrapper, (vm, cancel_delay, mig_data.dst,
                                            mig_data.vm_ports,
                                            not_wait_for_migration,
                                            mig_offline, mig_data)))
        utils_misc.parallel(multi_mig)

    def migrate_vms_dest(self, mig_data):
        """
        Migrate vms destination. This function is started on dest host during
        migration.

        :param mig_Data: Data for migration.
        """
        pass

    def __del__(self):
        if self.sync_server:
            self.sync_server.close()

    def master_id(self):
        return self.hosts[0]

    def _hosts_barrier(self, hosts, session_id, tag, timeout):
        logging.debug("Barrier timeout: %d tags: %s" % (timeout, tag))
        tags = SyncData(self.master_id(), self.hostid, hosts,
                        "%s,%s,barrier" % (str(session_id), tag),
                        self.sync_server).sync(tag, timeout)
        logging.debug("Barrier tag %s" % (tags))

    def preprocess_env(self):
        """
        Prepare env to start vms.
        """
        storage.preprocess_images(self.test.bindir, self.params, self.env)

    def _check_vms_source(self, mig_data):
        start_mig_tout = mig_data.params.get("start_migration_timeout", None)
        if start_mig_tout is None:
            for vm in mig_data.vms:
                vm.wait_for_login(timeout=self.login_timeout)

        if mig_data.params.get("host_mig_offline") != "yes":
            sync = SyncData(self.master_id(), self.hostid, mig_data.hosts,
                            mig_data.mig_id, self.sync_server)
            mig_data.vm_ports = sync.sync(timeout=240)[mig_data.dst]
            logging.info("Received from destination the migration port %s",
                         str(mig_data.vm_ports))

    def _check_vms_dest(self, mig_data):
        mig_data.vm_ports = {}
        for vm in mig_data.vms:
            logging.info("Communicating to source migration port %s",
                         vm.migration_port)
            mig_data.vm_ports[vm.name] = vm.migration_port

        if mig_data.params.get("host_mig_offline") != "yes":
            SyncData(self.master_id(), self.hostid,
                     mig_data.hosts, mig_data.mig_id,
                     self.sync_server).sync(mig_data.vm_ports, timeout=240)

    def _prepare_params(self, mig_data):
        """
        Prepare separate params for vm migration.

        :param vms_name: List of vms.
        """
        new_params = mig_data.params.copy()
        new_params["vms"] = " ".join(mig_data.vms_name)
        return new_params

    def _check_vms(self, mig_data):
        """
        Check if vms are started correctly.

        :param vms: list of vms.
        :param source: Must be True if is source machine.
        """
        if mig_data.is_src():
            self._check_vms_source(mig_data)
        else:
            self._check_vms_dest(mig_data)

    def _quick_check_vms(self, mig_data):
        """
        Check if vms are started correctly.

        :param vms: list of vms.
        :param source: Must be True if is source machine.
        """
        logging.info("Try check vms %s" % (mig_data.vms_name))
        for vm in mig_data.vms_name:
            if self.env.get_vm(vm) not in mig_data.vms:
                mig_data.vms.append(self.env.get_vm(vm))
        for vm in mig_data.vms:
            logging.info("Check vm %s on host %s" % (vm.name, self.hostid))
            vm.verify_alive()

    def prepare_for_migration(self, mig_data, migration_mode):
        """
        Prepare destination of migration for migration.

        :param mig_data: Class with data necessary for migration.
        :param migration_mode: Migration mode for prepare machine.
        """
        new_params = self._prepare_params(mig_data)

        new_params['migration_mode'] = migration_mode
        new_params['start_vm'] = 'yes'

        if self.params.get("migration_sync_vms", "no") == "yes":
            if mig_data.is_src():
                self.vm_lock.acquire()
                env_process.process(self.test, new_params, self.env,
                                    env_process.preprocess_image,
                                    env_process.preprocess_vm)
                self.vm_lock.release()
                self._quick_check_vms(mig_data)

                # Send vms configuration to dst host.
                vms = cPickle.dumps([self.env.get_vm(vm_name)
                                     for vm_name in mig_data.vms_name])

                self.env.get_vm(mig_data.vms_name[0]).monitor.info("qtree")
                SyncData(self.master_id(), self.hostid,
                         mig_data.hosts, mig_data.mig_id,
                         self.sync_server).sync(vms, timeout=240)
            elif mig_data.is_dst():
                # Load vms configuration from src host.
                vms = cPickle.loads(SyncData(self.master_id(), self.hostid,
                                             mig_data.hosts, mig_data.mig_id,
                                             self.sync_server).sync(timeout=240)[mig_data.src])
                for vm in vms:
                    # Save config to env. Used for create machine.
                    # When reuse_previous_config params is set don't check
                    # machine.
                    vm.address_cache = self.env.get("address_cache")
                    self.env.register_vm(vm.name, vm)

                self.vm_lock.acquire()
                env_process.process(self.test, new_params, self.env,
                                    env_process.preprocess_image,
                                    env_process.preprocess_vm)
                vms[0].monitor.info("qtree")
                self.vm_lock.release()
                self._quick_check_vms(mig_data)
        else:
            self.vm_lock.acquire()
            env_process.process(self.test, new_params, self.env,
                                env_process.preprocess_image,
                                env_process.preprocess_vm)
            self.vm_lock.release()
            self._quick_check_vms(mig_data)

        self._check_vms(mig_data)

    def migrate_vms(self, mig_data):
        """
        Migrate vms.
        """
        if mig_data.is_src():
            self.migrate_vms_src(mig_data)
        else:
            self.migrate_vms_dest(mig_data)

    def check_vms_dst(self, mig_data):
        """
        Check vms after migrate.

        :param mig_data: object with migration data.
        """
        for vm in mig_data.vms:
            vm.resume()
            if not guest_active(vm):
                raise error.TestFail("Guest not active after migration")

        logging.info("Migrated guest appears to be running")

        logging.info("Logging into migrated guest after migration...")
        for vm in mig_data.vms:
            if self.regain_ip_cmd is not None:
                session_serial = vm.wait_for_serial_login(timeout=self.login_timeout)
                # There is sometime happen that system sends some message on
                # serial console and IP renew command block test. Because
                # there must be added "sleep" in IP renew command.
                session_serial.cmd(self.regain_ip_cmd)

            if not self.not_login_after_mig:
                vm.wait_for_login(timeout=self.login_timeout)

    def check_vms_src(self, mig_data):
        """
        Check vms after migrate.

        :param mig_data: object with migration data.
        """
        pass

    def postprocess_env(self):
        """
        Kill vms and delete cloned images.
        """
        pass

    def before_migration(self, mig_data):
        """
        Do something right before migration.

        :param mig_data: object with migration data.
        """
        pass

    def migrate(self, vms_name, srchost, dsthost, start_work=None,
                check_work=None, mig_mode="tcp", params_append=None):
        """
        Migrate machine from srchost to dsthost. It executes start_work on
        source machine before migration and executes check_work on dsthost
        after migration.

        Migration execution progress:

        ::

            source host                   |   dest host
            --------------------------------------------------------
               prepare guest on both sides of migration
                - start machine and check if machine works
                - synchronize transfer data needed for migration
            --------------------------------------------------------
            start work on source guests   |   wait for migration
            --------------------------------------------------------
                         migrate guest to dest host.
                  wait on finish migration synchronization
            --------------------------------------------------------
                                          |   check work on vms
            --------------------------------------------------------
                        wait for sync on finish migration

        :param vms_name: List of vms.
        :param srchost: src host id.
        :param dsthost: dst host id.
        :param start_work: Function started before migration.
        :param check_work: Function started after migration.
        :param mig_mode: Migration mode.
        :param params_append: Append params to self.params only for migration.
        """
        def migrate_wrap(vms_name, srchost, dsthost, start_work=None,
                         check_work=None, params_append=None):
            logging.info("Starting migrate vms %s from host %s to %s" %
                         (vms_name, srchost, dsthost))
            pause = self.params.get("paused_after_start_vm")
            mig_error = None
            mig_data = MigrationData(self.params, srchost, dsthost,
                                     vms_name, params_append)
            cancel_delay = self.params.get("cancel_delay", None)
            host_offline_migration = self.params.get("host_mig_offline")

            try:
                try:
                    if mig_data.is_src():
                        self.prepare_for_migration(mig_data, None)
                    elif self.hostid == dsthost:
                        if host_offline_migration != "yes":
                            self.prepare_for_migration(mig_data, mig_mode)
                    else:
                        return

                    if mig_data.is_src():
                        if start_work:
                            if pause != "yes":
                                start_work(mig_data)
                            else:
                                raise error.TestNAError("Can't start work if "
                                                        "vm is paused.")

                    # Starts VM and waits timeout before migration.
                    if pause == "yes" and mig_data.is_src():
                        for vm in mig_data.vms:
                            vm.resume()
                        wait = self.params.get("start_migration_timeout", 0)
                        logging.debug("Wait for migration %s seconds." %
                                      (wait))
                        time.sleep(int(wait))

                    self.before_migration(mig_data)

                    self.migrate_vms(mig_data)

                    timeout = 60
                    if cancel_delay is None:
                        if host_offline_migration == "yes":
                            self._hosts_barrier(self.hosts,
                                                mig_data.mig_id,
                                                'wait_for_offline_mig',
                                                self.finish_timeout)
                            if mig_data.is_dst():
                                self.prepare_for_migration(mig_data, mig_mode)
                            self._hosts_barrier(self.hosts,
                                                mig_data.mig_id,
                                                'wait2_for_offline_mig',
                                                self.finish_timeout)

                        if (not mig_data.is_src()):
                            timeout = self.mig_timeout
                        self._hosts_barrier(mig_data.hosts, mig_data.mig_id,
                                            'mig_finished', timeout)

                        if mig_data.is_dst():
                            self.check_vms_dst(mig_data)
                            if check_work:
                                check_work(mig_data)
                        else:
                            self.check_vms_src(mig_data)
                            if check_work:
                                check_work(mig_data)
                except:
                    mig_error = True
                    raise
            finally:
                if mig_error and cancel_delay is not None:
                    self._hosts_barrier(self.hosts,
                                        mig_data.mig_id,
                                        'test_finihed',
                                        self.finish_timeout)
                elif mig_error:
                    raise

        def wait_wrap(vms_name, srchost, dsthost):
            mig_data = MigrationData(self.params, srchost, dsthost, vms_name,
                                     None)
            timeout = (self.login_timeout + self.mig_timeout +
                       self.finish_timeout)

            self._hosts_barrier(self.hosts, mig_data.mig_id,
                                'test_finihed', timeout)

        if (self.hostid in [srchost, dsthost]):
            mig_thread = utils.InterruptedThread(migrate_wrap, (vms_name,
                                                                srchost,
                                                                dsthost,
                                                                start_work,
                                                                check_work,
                                                                params_append))
        else:
            mig_thread = utils.InterruptedThread(wait_wrap, (vms_name,
                                                             srchost,
                                                             dsthost))
        mig_thread.start()
        return mig_thread

    def migrate_wait(self, vms_name, srchost, dsthost, start_work=None,
                     check_work=None, mig_mode="tcp", params_append=None):
        """
        Migrate machine from srchost to dsthost and wait for finish.
        It executes start_work on source machine before migration and executes
        check_work on dsthost after migration.

        :param vms_name: List of vms.
        :param srchost: src host id.
        :param dsthost: dst host id.
        :param start_work: Function which is started before migration.
        :param check_work: Function which is started after
                           done of migration.
        """
        self.migrate(vms_name, srchost, dsthost, start_work, check_work,
                     mig_mode, params_append).join()

    def cleanup(self):
        """
        Cleanup env after test.
        """
        if self.clone_master:
            self.sync_server.close()
            self.postprocess_env()

    def run(self):
        """
        Start multihost migration scenario.
        After scenario is finished or if scenario crashed it calls postprocess
        machines and cleanup env.
        """
        try:
            self.migration_scenario()

            self._hosts_barrier(self.hosts, self.hosts, 'all_test_finished',
                                self.finish_timeout)
        finally:
            self.cleanup()