'Migrates a running instance to a new machine.
:param server: instance id which comes from nova list.
:param host: destination host name.
:param block_migration: if True, do block_migration.
:param disk_over_commit: if True, allow disk overcommit.
:returns: An instance of novaclient.base.TupleWithMeta'

@api_versions.wraps('2.0', '2.24')
def live_migrate(self, server, host, block_migration, disk_over_commit):

    return self._action('os-migrateLive', server, {'host': host, 'block_migration': block_migration, 'disk_over_commit': disk_over_commit})
