def compute_instance_id(self):
        if self._instance_id is None:
            self._instance_id = self._api.compute_instance_id()
        return self._instance_id
Always return initial result since this shouldn't change until a
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/blockdevice.py/ProcessLifetimeCache.compute_instance_id