Beispiel #1
0
    def __init__(self,
                 config_path,
                 load_metrics,
                 max_launch_batch=AUTOSCALER_MAX_LAUNCH_BATCH,
                 max_concurrent_launches=AUTOSCALER_MAX_CONCURRENT_LAUNCHES,
                 max_failures=AUTOSCALER_MAX_NUM_FAILURES,
                 process_runner=subprocess,
                 update_interval_s=AUTOSCALER_UPDATE_INTERVAL_S):
        self.config_path = config_path
        self.reset(errors_fatal=True)
        self.load_metrics = load_metrics

        self.max_failures = max_failures
        self.max_launch_batch = max_launch_batch
        self.max_concurrent_launches = max_concurrent_launches
        self.process_runner = process_runner

        # Map from node_id to NodeUpdater processes
        self.updaters = {}
        self.num_failed_updates = defaultdict(int)
        self.num_successful_updates = defaultdict(int)
        self.num_failures = 0
        self.last_update_time = 0.0
        self.update_interval_s = update_interval_s
        self.bringup = True

        # Node launchers
        self.launch_queue = queue.Queue()
        self.pending_launches = ConcurrentCounter()
        max_batches = math.ceil(max_concurrent_launches /
                                float(max_launch_batch))
        for i in range(int(max_batches)):
            node_launcher = NodeLauncher(
                provider=self.provider,
                queue=self.launch_queue,
                index=i,
                pending=self.pending_launches,
                node_types=self.available_node_types,
            )
            node_launcher.daemon = True
            node_launcher.start()

        # Expand local file_mounts to allow ~ in the paths. This can't be done
        # earlier when the config is written since we might be on different
        # platform and the expansion would result in wrong path.
        self.config["file_mounts"] = {
            remote: os.path.expanduser(local)
            for remote, local in self.config["file_mounts"].items()
        }

        for local_path in self.config["file_mounts"].values():
            assert os.path.exists(local_path)

        # Aggregate resources the user is requesting of the cluster.
        self.resource_requests = defaultdict(int)
        # List of resource bundles the user is requesting of the cluster.
        self.resource_demand_vector = []

        logger.info("StandardAutoscaler: {}".format(self.config))
Beispiel #2
0
class StandardAutoscaler:
    """The autoscaling control loop for a Ray cluster.

    There are two ways to start an autoscaling cluster: manually by running
    `ray start --head --autoscaling-config=/path/to/config.yaml` on a
    instance that has permission to launch other instances, or you can also use
    `ray create_or_update /path/to/config.yaml` from your laptop, which will
    configure the right AWS/Cloud roles automatically.

    StandardAutoscaler's `update` method is periodically called by `monitor.py`
    to add and remove nodes as necessary. Currently, load-based autoscaling is
    not implemented, so all this class does is try to maintain a constant
    cluster size.

    StandardAutoscaler is also used to bootstrap clusters (by adding workers
    until the target cluster size is met).
    """
    def __init__(self,
                 config_path,
                 load_metrics,
                 max_launch_batch=AUTOSCALER_MAX_LAUNCH_BATCH,
                 max_concurrent_launches=AUTOSCALER_MAX_CONCURRENT_LAUNCHES,
                 max_failures=AUTOSCALER_MAX_NUM_FAILURES,
                 process_runner=subprocess,
                 update_interval_s=AUTOSCALER_UPDATE_INTERVAL_S):
        self.config_path = config_path
        self.reload_config(errors_fatal=True)
        self.load_metrics = load_metrics
        self.provider = get_node_provider(self.config["provider"],
                                          self.config["cluster_name"])

        self.max_failures = max_failures
        self.max_launch_batch = max_launch_batch
        self.max_concurrent_launches = max_concurrent_launches
        self.process_runner = process_runner

        # Map from node_id to NodeUpdater processes
        self.updaters = {}
        self.num_failed_updates = defaultdict(int)
        self.num_successful_updates = defaultdict(int)
        self.num_failures = 0
        self.last_update_time = 0.0
        self.update_interval_s = update_interval_s
        self.bringup = True

        # Node launchers
        self.launch_queue = queue.Queue()
        self.pending_launches = ConcurrentCounter()
        max_batches = math.ceil(max_concurrent_launches /
                                float(max_launch_batch))
        for i in range(int(max_batches)):
            node_launcher = NodeLauncher(provider=self.provider,
                                         queue=self.launch_queue,
                                         index=i,
                                         pending=self.pending_launches)
            node_launcher.daemon = True
            node_launcher.start()

        # Expand local file_mounts to allow ~ in the paths. This can't be done
        # earlier when the config is written since we might be on different
        # platform and the expansion would result in wrong path.
        self.config["file_mounts"] = {
            remote: os.path.expanduser(local)
            for remote, local in self.config["file_mounts"].items()
        }

        for local_path in self.config["file_mounts"].values():
            assert os.path.exists(local_path)

        self.resource_requests = defaultdict(int)

        logger.info("StandardAutoscaler: {}".format(self.config))

    def update(self):
        try:
            self.reload_config(errors_fatal=False)
            self._update()
        except Exception as e:
            logger.exception("StandardAutoscaler: "
                             "Error during autoscaling.")
            self.num_failures += 1
            if self.num_failures > self.max_failures:
                logger.critical("StandardAutoscaler: "
                                "Too many errors, abort.")
                raise e

    def _update(self):
        now = time.time()

        # Throttle autoscaling updates to this interval to avoid exceeding
        # rate limits on API calls.
        if now - self.last_update_time < self.update_interval_s:
            return

        self.last_update_time = now
        nodes = self.workers()
        self.load_metrics.prune_active_ips(
            [self.provider.internal_ip(node_id) for node_id in nodes])
        target_workers = self.target_num_workers()

        if len(nodes) >= target_workers:
            if "CPU" in self.resource_requests:
                del self.resource_requests["CPU"]

        self.log_info_string(nodes, target_workers)

        # Terminate any idle or out of date nodes
        last_used = self.load_metrics.last_used_time_by_ip
        horizon = now - (60 * self.config["idle_timeout_minutes"])

        nodes_to_terminate = []
        for node_id in nodes:
            node_ip = self.provider.internal_ip(node_id)
            if node_ip in last_used and last_used[node_ip] < horizon and \
                    len(nodes) - len(nodes_to_terminate) > target_workers:
                logger.info("StandardAutoscaler: "
                            "{}: Terminating idle node".format(node_id))
                nodes_to_terminate.append(node_id)
            elif not self.launch_config_ok(node_id):
                logger.info("StandardAutoscaler: "
                            "{}: Terminating outdated node".format(node_id))
                nodes_to_terminate.append(node_id)

        if nodes_to_terminate:
            self.provider.terminate_nodes(nodes_to_terminate)
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)

        # Terminate nodes if there are too many
        nodes_to_terminate = []
        while len(nodes) > self.config["max_workers"]:
            logger.info("StandardAutoscaler: "
                        "{}: Terminating unneeded node".format(nodes[-1]))
            nodes_to_terminate.append(nodes[-1])
            nodes = nodes[:-1]

        if nodes_to_terminate:
            self.provider.terminate_nodes(nodes_to_terminate)
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)

        # Launch additional nodes of the default type, if still needed.
        num_pending = self.pending_launches.value
        num_workers = len(nodes) + num_pending
        if num_workers < target_workers:
            max_allowed = min(self.max_launch_batch,
                              self.max_concurrent_launches - num_pending)

            num_launches = min(max_allowed, target_workers - num_workers)
            self.launch_new_node(num_launches, instance_type=None)
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)
        elif self.load_metrics.num_workers_connected() >= target_workers:
            logger.info("Ending bringup phase")
            self.bringup = False
            self.log_info_string(nodes, target_workers)

        # Process any completed updates
        completed = []
        for node_id, updater in self.updaters.items():
            if not updater.is_alive():
                completed.append(node_id)
        if completed:
            for node_id in completed:
                if self.updaters[node_id].exitcode == 0:
                    self.num_successful_updates[node_id] += 1
                else:
                    self.num_failed_updates[node_id] += 1
                del self.updaters[node_id]
            # Mark the node as active to prevent the node recovery logic
            # immediately trying to restart Ray on the new node.
            self.load_metrics.mark_active(self.provider.internal_ip(node_id))
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)

        # Update nodes with out-of-date files.
        # TODO(edoakes): Spawning these threads directly seems to cause
        # problems. They should at a minimum be spawned as daemon threads.
        # See https://github.com/ray-project/ray/pull/5903 for more info.
        T = []
        for node_id, commands, ray_start in (self.should_update(node_id)
                                             for node_id in nodes):
            if node_id is not None:
                T.append(
                    threading.Thread(target=self.spawn_updater,
                                     args=(node_id, commands, ray_start)))
        for t in T:
            t.start()
        for t in T:
            t.join()

        # Attempt to recover unhealthy nodes
        for node_id in nodes:
            self.recover_if_needed(node_id, now)

    def reload_config(self, errors_fatal=False):
        try:
            with open(self.config_path) as f:
                new_config = yaml.safe_load(f.read())
            validate_config(new_config)
            new_launch_hash = hash_launch_conf(new_config["worker_nodes"],
                                               new_config["auth"])
            new_runtime_hash = hash_runtime_conf(new_config["file_mounts"], [
                new_config["worker_setup_commands"],
                new_config["worker_start_ray_commands"]
            ])
            self.config = new_config
            self.launch_hash = new_launch_hash
            self.runtime_hash = new_runtime_hash
        except Exception as e:
            if errors_fatal:
                raise e
            else:
                logger.exception("StandardAutoscaler: "
                                 "Error parsing config.")

    def target_num_workers(self):
        target_frac = self.config["target_utilization_fraction"]
        cur_used = self.load_metrics.approx_workers_used()
        ideal_num_nodes = int(np.ceil(cur_used / float(target_frac)))
        ideal_num_workers = ideal_num_nodes - 1  # subtract 1 for head node

        initial_workers = self.config["initial_workers"]
        aggressive = self.config["autoscaling_mode"] == "aggressive"
        if self.bringup:
            ideal_num_workers = max(ideal_num_workers, initial_workers)
        elif aggressive and cur_used > 0:
            # If we want any workers, we want at least initial_workers
            ideal_num_workers = max(ideal_num_workers, initial_workers)

        # Other resources are not supported at present.
        if "CPU" in self.resource_requests:
            try:
                cores_per_worker = self.config["worker_nodes"]["Resources"][
                    "CPU"]
            except KeyError:
                cores_per_worker = 1  # Assume the worst

            cores_desired = self.resource_requests["CPU"]

            ideal_num_workers = max(
                ideal_num_workers,
                int(np.ceil(cores_desired / cores_per_worker)))

        return min(self.config["max_workers"],
                   max(self.config["min_workers"], ideal_num_workers))

    def launch_config_ok(self, node_id):
        launch_conf = self.provider.node_tags(node_id).get(
            TAG_RAY_LAUNCH_CONFIG)
        if self.launch_hash != launch_conf:
            return False
        return True

    def files_up_to_date(self, node_id):
        applied = self.provider.node_tags(node_id).get(TAG_RAY_RUNTIME_CONFIG)
        if applied != self.runtime_hash:
            logger.info("StandardAutoscaler: "
                        "{}: Runtime state is {}, want {}".format(
                            node_id, applied, self.runtime_hash))
            return False
        return True

    def recover_if_needed(self, node_id, now):
        if not self.can_update(node_id):
            return
        key = self.provider.internal_ip(node_id)
        if key not in self.load_metrics.last_heartbeat_time_by_ip:
            self.load_metrics.last_heartbeat_time_by_ip[key] = now
        last_heartbeat_time = self.load_metrics.last_heartbeat_time_by_ip[key]
        delta = now - last_heartbeat_time
        if delta < AUTOSCALER_HEARTBEAT_TIMEOUT_S:
            return
        logger.warning("StandardAutoscaler: "
                       "{}: No heartbeat in {}s, "
                       "restarting Ray to recover...".format(node_id, delta))
        updater = NodeUpdaterThread(
            node_id=node_id,
            provider_config=self.config["provider"],
            provider=self.provider,
            auth_config=self.config["auth"],
            cluster_name=self.config["cluster_name"],
            file_mounts={},
            initialization_commands=[],
            setup_commands=[],
            ray_start_commands=with_head_node_ip(
                self.config["worker_start_ray_commands"]),
            runtime_hash=self.runtime_hash,
            process_runner=self.process_runner,
            use_internal_ip=True,
            docker_config=self.config.get("docker"))
        updater.start()
        self.updaters[node_id] = updater

    def should_update(self, node_id):
        if not self.can_update(node_id):
            return None, None, None  # no update

        status = self.provider.node_tags(node_id).get(TAG_RAY_NODE_STATUS)
        if status == STATUS_UP_TO_DATE and self.files_up_to_date(node_id):
            return None, None, None  # no update

        successful_updated = self.num_successful_updates.get(node_id, 0) > 0
        if successful_updated and self.config.get("restart_only", False):
            init_commands = []
            ray_commands = self.config["worker_start_ray_commands"]
        elif successful_updated and self.config.get("no_restart", False):
            init_commands = self.config["worker_setup_commands"]
            ray_commands = []
        else:
            init_commands = self.config["worker_setup_commands"]
            ray_commands = self.config["worker_start_ray_commands"]

        return (node_id, init_commands, ray_commands)

    def spawn_updater(self, node_id, init_commands, ray_start_commands):
        updater = NodeUpdaterThread(
            node_id=node_id,
            provider_config=self.config["provider"],
            provider=self.provider,
            auth_config=self.config["auth"],
            cluster_name=self.config["cluster_name"],
            file_mounts=self.config["file_mounts"],
            initialization_commands=with_head_node_ip(
                self.config["initialization_commands"]),
            setup_commands=with_head_node_ip(init_commands),
            ray_start_commands=with_head_node_ip(ray_start_commands),
            runtime_hash=self.runtime_hash,
            process_runner=self.process_runner,
            use_internal_ip=True,
            docker_config=self.config.get("docker"))
        updater.start()
        self.updaters[node_id] = updater

    def can_update(self, node_id):
        if node_id in self.updaters:
            return False
        if not self.launch_config_ok(node_id):
            return False
        if self.num_failed_updates.get(node_id, 0) > 0:  # TODO(ekl) retry?
            return False
        return True

    def launch_new_node(self, count, instance_type):
        logger.info(
            "StandardAutoscaler: Queue {} new nodes for launch".format(count))
        self.pending_launches.inc(instance_type, count)
        config = copy.deepcopy(self.config)
        self.launch_queue.put((config, count, instance_type))

    def workers(self):
        return self.provider.non_terminated_nodes(
            tag_filters={TAG_RAY_NODE_TYPE: NODE_TYPE_WORKER})

    def log_info_string(self, nodes, target):
        logger.info("StandardAutoscaler: {}".format(
            self.info_string(nodes, target)))
        logger.info("LoadMetrics: {}".format(self.load_metrics.info_string()))

    def info_string(self, nodes, target):
        suffix = ""
        if self.pending_launches:
            suffix += " ({} pending)".format(self.pending_launches.value)
        if self.updaters:
            suffix += " ({} updating)".format(len(self.updaters))
        if self.num_failed_updates:
            suffix += " ({} failed to update)".format(
                len(self.num_failed_updates))
        if self.bringup:
            suffix += " (bringup=True)"

        return "{}/{} target nodes{}".format(len(nodes), target, suffix)

    def request_resources(self, resources):
        for resource, count in resources.items():
            self.resource_requests[resource] = max(
                self.resource_requests[resource], count)

        logger.info("StandardAutoscaler: resource_requests={}".format(
            self.resource_requests))

    def kill_workers(self):
        logger.error("StandardAutoscaler: kill_workers triggered")
        nodes = self.workers()
        if nodes:
            self.provider.terminate_nodes(nodes)
        logger.error("StandardAutoscaler: terminated {} node(s)".format(
            len(nodes)))
Beispiel #3
0
class StandardAutoscaler:
    """The autoscaling control loop for a Ray cluster.

    There are two ways to start an autoscaling cluster: manually by running
    `ray start --head --autoscaling-config=/path/to/config.yaml` on a
    instance that has permission to launch other instances, or you can also use
    `ray create_or_update /path/to/config.yaml` from your laptop, which will
    configure the right AWS/Cloud roles automatically.

    StandardAutoscaler's `update` method is periodically called by `monitor.py`
    to add and remove nodes as necessary. Currently, load-based autoscaling is
    not implemented, so all this class does is try to maintain a constant
    cluster size.

    StandardAutoscaler is also used to bootstrap clusters (by adding workers
    until the target cluster size is met).
    """
    def __init__(self,
                 config_path,
                 load_metrics,
                 max_launch_batch=AUTOSCALER_MAX_LAUNCH_BATCH,
                 max_concurrent_launches=AUTOSCALER_MAX_CONCURRENT_LAUNCHES,
                 max_failures=AUTOSCALER_MAX_NUM_FAILURES,
                 process_runner=subprocess,
                 update_interval_s=AUTOSCALER_UPDATE_INTERVAL_S):
        self.config_path = config_path
        # Keep this before self.reset (self.provider needs to be created
        # exactly once).
        self.provider = None
        self.reset(errors_fatal=True)
        self.load_metrics = load_metrics

        self.max_failures = max_failures
        self.max_launch_batch = max_launch_batch
        self.max_concurrent_launches = max_concurrent_launches
        self.process_runner = process_runner

        # Map from node_id to NodeUpdater processes
        self.updaters = {}
        self.num_failed_updates = defaultdict(int)
        self.num_successful_updates = defaultdict(int)
        self.num_failures = 0
        self.last_update_time = 0.0
        self.update_interval_s = update_interval_s
        self.bringup = True

        # Node launchers
        self.launch_queue = queue.Queue()
        self.pending_launches = ConcurrentCounter()
        max_batches = math.ceil(max_concurrent_launches /
                                float(max_launch_batch))
        for i in range(int(max_batches)):
            node_launcher = NodeLauncher(
                provider=self.provider,
                queue=self.launch_queue,
                index=i,
                pending=self.pending_launches,
                node_types=self.available_node_types,
            )
            node_launcher.daemon = True
            node_launcher.start()

        # Expand local file_mounts to allow ~ in the paths. This can't be done
        # earlier when the config is written since we might be on different
        # platform and the expansion would result in wrong path.
        self.config["file_mounts"] = {
            remote: os.path.expanduser(local)
            for remote, local in self.config["file_mounts"].items()
        }

        for local_path in self.config["file_mounts"].values():
            assert os.path.exists(local_path)

        # Aggregate resources the user is requesting of the cluster.
        self.resource_requests = defaultdict(int)
        # List of resource bundles the user is requesting of the cluster.
        self.resource_demand_vector = []

        logger.info("StandardAutoscaler: {}".format(self.config))

    def update(self):
        try:
            self.reset(errors_fatal=False)
            self._update()
        except Exception as e:
            logger.exception("StandardAutoscaler: "
                             "Error during autoscaling.")
            if _internal_kv_initialized():
                _internal_kv_put(DEBUG_AUTOSCALING_ERROR,
                                 str(e),
                                 overwrite=True)
            self.num_failures += 1
            if self.num_failures > self.max_failures:
                logger.critical("StandardAutoscaler: "
                                "Too many errors, abort.")
                raise e

    def _update(self):
        now = time.time()

        # Throttle autoscaling updates to this interval to avoid exceeding
        # rate limits on API calls.
        if now - self.last_update_time < self.update_interval_s:
            return

        self.last_update_time = now
        nodes = self.workers()
        # Check pending nodes immediately after fetching the number of running
        # nodes to minimize chance number of pending nodes changing after
        # additional nodes (managed and unmanaged) are launched.
        num_pending = self.pending_launches.value
        self.load_metrics.prune_active_ips([
            self.provider.internal_ip(node_id)
            for node_id in self.all_workers()
        ])
        target_workers = self.target_num_workers()

        if len(nodes) >= target_workers:
            if "CPU" in self.resource_requests:
                del self.resource_requests["CPU"]

        self.log_info_string(nodes, target_workers)

        # Terminate any idle or out of date nodes
        last_used = self.load_metrics.last_used_time_by_ip
        horizon = now - (60 * self.config["idle_timeout_minutes"])

        nodes_to_terminate = []
        for node_id in nodes:
            node_ip = self.provider.internal_ip(node_id)
            if (node_ip in last_used and last_used[node_ip] < horizon) and \
                    (len(nodes) - len(nodes_to_terminate)
                     > target_workers):
                logger.info("StandardAutoscaler: "
                            "{}: Terminating idle node".format(node_id))
                nodes_to_terminate.append(node_id)
            elif not self.launch_config_ok(node_id):
                logger.info("StandardAutoscaler: "
                            "{}: Terminating outdated node".format(node_id))
                nodes_to_terminate.append(node_id)

        if nodes_to_terminate:
            self.provider.terminate_nodes(nodes_to_terminate)
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)

        # Terminate nodes if there are too many
        nodes_to_terminate = []
        while (len(nodes) -
               len(nodes_to_terminate)) > self.config["max_workers"] and nodes:
            to_terminate = nodes.pop()
            logger.info("StandardAutoscaler: "
                        "{}: Terminating unneeded node".format(to_terminate))
            nodes_to_terminate.append(to_terminate)

        if nodes_to_terminate:
            self.provider.terminate_nodes(nodes_to_terminate)
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)

        # First let the resource demand scheduler launch nodes, if enabled.
        if self.resource_demand_scheduler:
            resource_demand_vector = self.resource_demand_vector + \
                self.load_metrics.get_resource_demand_vector()
            if resource_demand_vector:
                to_launch = (
                    self.resource_demand_scheduler.get_nodes_to_launch(
                        self.provider.non_terminated_nodes(tag_filters={}),
                        self.pending_launches.breakdown(),
                        resource_demand_vector,
                        self.load_metrics.get_resource_utilization()))
                # TODO(ekl) also enforce max launch concurrency here?
                for node_type, count in to_launch:
                    self.launch_new_node(count, node_type=node_type)

            num_pending = self.pending_launches.value
            nodes = self.workers()

        # Launch additional nodes of the default type, if still needed.
        num_workers = len(nodes) + num_pending
        if num_workers < target_workers:
            max_allowed = min(self.max_launch_batch,
                              self.max_concurrent_launches - num_pending)

            num_launches = min(max_allowed, target_workers - num_workers)
            self.launch_new_node(num_launches,
                                 self.config.get("worker_default_node_type"))
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)
        elif self.load_metrics.num_workers_connected() >= target_workers:
            self.bringup = False
            self.log_info_string(nodes, target_workers)

        # Process any completed updates
        completed = []
        for node_id, updater in self.updaters.items():
            if not updater.is_alive():
                completed.append(node_id)
        if completed:
            for node_id in completed:
                if self.updaters[node_id].exitcode == 0:
                    self.num_successful_updates[node_id] += 1
                else:
                    self.num_failed_updates[node_id] += 1
                del self.updaters[node_id]
            # Mark the node as active to prevent the node recovery logic
            # immediately trying to restart Ray on the new node.
            self.load_metrics.mark_active(self.provider.internal_ip(node_id))
            nodes = self.workers()
            self.log_info_string(nodes, target_workers)

        # Update nodes with out-of-date files.
        # TODO(edoakes): Spawning these threads directly seems to cause
        # problems. They should at a minimum be spawned as daemon threads.
        # See https://github.com/ray-project/ray/pull/5903 for more info.
        T = []
        for node_id, commands, ray_start, docker_config in (
                self.should_update(node_id) for node_id in nodes):
            if node_id is not None:
                resources = self._node_resources(node_id)
                logger.debug(f"{node_id}: Starting new thread runner.")
                T.append(
                    threading.Thread(target=self.spawn_updater,
                                     args=(node_id, commands, ray_start,
                                           resources, docker_config)))
        for t in T:
            t.start()
        for t in T:
            t.join()

        # Attempt to recover unhealthy nodes
        for node_id in nodes:
            self.recover_if_needed(node_id, now)

    def _node_resources(self, node_id):
        node_type = self.provider.node_tags(node_id).get(
            TAG_RAY_USER_NODE_TYPE)
        if self.available_node_types:
            return self.available_node_types.get(node_type,
                                                 {}).get("resources", {})
        else:
            return {}

    def reset(self, errors_fatal=False):
        sync_continuously = False
        if hasattr(self, "config"):
            sync_continuously = self.config.get(
                "file_mounts_sync_continuously", False)
        try:
            with open(self.config_path) as f:
                new_config = yaml.safe_load(f.read())
            validate_config(new_config)
            (new_runtime_hash,
             new_file_mounts_contents_hash) = hash_runtime_conf(
                 new_config["file_mounts"],
                 new_config["cluster_synced_files"],
                 [
                     new_config["worker_setup_commands"],
                     new_config["worker_start_ray_commands"],
                 ],
                 generate_file_mounts_contents_hash=sync_continuously,
             )
            self.config = new_config
            self.runtime_hash = new_runtime_hash
            self.file_mounts_contents_hash = new_file_mounts_contents_hash
            if not self.provider:
                self.provider = get_node_provider(self.config["provider"],
                                                  self.config["cluster_name"])
            # Check whether we can enable the resource demand scheduler.
            if "available_node_types" in self.config:
                self.available_node_types = self.config["available_node_types"]
                self.resource_demand_scheduler = ResourceDemandScheduler(
                    self.provider, self.available_node_types,
                    self.config["max_workers"])
            else:
                self.available_node_types = None
                self.resource_demand_scheduler = None

        except Exception as e:
            if errors_fatal:
                raise e
            else:
                logger.exception("StandardAutoscaler: "
                                 "Error parsing config.")

    def target_num_workers(self):
        target_frac = self.config["target_utilization_fraction"]
        cur_used = self.load_metrics.approx_workers_used()
        ideal_num_nodes = int(np.ceil(cur_used / float(target_frac)))
        ideal_num_workers = ideal_num_nodes - 1  # subtract 1 for head node

        initial_workers = self.config["initial_workers"]
        aggressive = self.config["autoscaling_mode"] == "aggressive"
        if self.bringup:
            ideal_num_workers = max(ideal_num_workers, initial_workers)
        elif aggressive and cur_used > 0:
            # If we want any workers, we want at least initial_workers
            ideal_num_workers = max(ideal_num_workers, initial_workers)

        # Other resources are not supported at present.
        if "CPU" in self.resource_requests:
            try:
                cores_per_worker = self.config["worker_nodes"]["Resources"][
                    "CPU"]
            except KeyError:
                cores_per_worker = 1  # Assume the worst

            cores_desired = self.resource_requests["CPU"]

            ideal_num_workers = max(
                ideal_num_workers,
                int(np.ceil(cores_desired / cores_per_worker)))

        return min(self.config["max_workers"],
                   max(self.config["min_workers"], ideal_num_workers))

    def launch_config_ok(self, node_id):
        node_tags = self.provider.node_tags(node_id)
        tag_launch_conf = node_tags.get(TAG_RAY_LAUNCH_CONFIG)
        node_type = node_tags.get(TAG_RAY_USER_NODE_TYPE)

        launch_config = copy.deepcopy(self.config["worker_nodes"])
        if node_type:
            launch_config.update(
                self.config["available_node_types"][node_type]["node_config"])
        calculated_launch_hash = hash_launch_conf(launch_config,
                                                  self.config["auth"])

        if calculated_launch_hash != tag_launch_conf:
            return False
        return True

    def files_up_to_date(self, node_id):
        node_tags = self.provider.node_tags(node_id)
        applied_config_hash = node_tags.get(TAG_RAY_RUNTIME_CONFIG)
        applied_file_mounts_contents_hash = node_tags.get(
            TAG_RAY_FILE_MOUNTS_CONTENTS)
        if (applied_config_hash != self.runtime_hash
                or (self.file_mounts_contents_hash is not None
                    and self.file_mounts_contents_hash !=
                    applied_file_mounts_contents_hash)):
            logger.info("StandardAutoscaler: "
                        "{}: Runtime state is ({},{}), want ({},{})".format(
                            node_id, applied_config_hash,
                            applied_file_mounts_contents_hash,
                            self.runtime_hash, self.file_mounts_contents_hash))
            return False
        return True

    def recover_if_needed(self, node_id, now):
        if not self.can_update(node_id):
            return
        key = self.provider.internal_ip(node_id)
        if key not in self.load_metrics.last_heartbeat_time_by_ip:
            self.load_metrics.last_heartbeat_time_by_ip[key] = now
        last_heartbeat_time = self.load_metrics.last_heartbeat_time_by_ip[key]
        delta = now - last_heartbeat_time
        if delta < AUTOSCALER_HEARTBEAT_TIMEOUT_S:
            return
        logger.warning("StandardAutoscaler: "
                       "{}: No heartbeat in {}s, "
                       "restarting Ray to recover...".format(node_id, delta))
        updater = NodeUpdaterThread(
            node_id=node_id,
            provider_config=self.config["provider"],
            provider=self.provider,
            auth_config=self.config["auth"],
            cluster_name=self.config["cluster_name"],
            file_mounts={},
            initialization_commands=[],
            setup_commands=[],
            ray_start_commands=with_head_node_ip(
                self.config["worker_start_ray_commands"]),
            runtime_hash=self.runtime_hash,
            file_mounts_contents_hash=self.file_mounts_contents_hash,
            process_runner=self.process_runner,
            use_internal_ip=True,
            is_head_node=False,
            docker_config=self.config.get("docker"))
        updater.start()
        self.updaters[node_id] = updater

    def _get_node_type_specific_fields(self, node_id: str,
                                       fields_key: str) -> Any:
        fields = self.config[fields_key]
        node_tags = self.provider.node_tags(node_id)
        if TAG_RAY_USER_NODE_TYPE in node_tags:
            node_type = node_tags[TAG_RAY_USER_NODE_TYPE]
            if node_type not in self.available_node_types:
                raise ValueError(f"Unknown node type tag: {node_type}.")
            node_specific_config = self.available_node_types[node_type]
            if fields_key in node_specific_config:
                fields = node_specific_config[fields_key]
        return fields

    def _get_node_specific_docker_config(self, node_id):
        if "docker" not in self.config:
            return {}
        docker_config = copy.deepcopy(self.config.get("docker", {}))
        node_specific_docker = self._get_node_type_specific_fields(
            node_id, "docker")
        docker_config.update(node_specific_docker)
        return docker_config

    def should_update(self, node_id):
        if not self.can_update(node_id):
            return UpdateInstructions(None, None, None, None)  # no update

        status = self.provider.node_tags(node_id).get(TAG_RAY_NODE_STATUS)
        if status == STATUS_UP_TO_DATE and self.files_up_to_date(node_id):
            return UpdateInstructions(None, None, None, None)  # no update

        successful_updated = self.num_successful_updates.get(node_id, 0) > 0
        if successful_updated and self.config.get("restart_only", False):
            init_commands = []
            ray_commands = self.config["worker_start_ray_commands"]
        elif successful_updated and self.config.get("no_restart", False):
            init_commands = self._get_node_type_specific_fields(
                node_id, "worker_setup_commands")
            ray_commands = []
        else:
            init_commands = self._get_node_type_specific_fields(
                node_id, "worker_setup_commands")
            ray_commands = self.config["worker_start_ray_commands"]

        docker_config = self._get_node_specific_docker_config(node_id)
        return UpdateInstructions(node_id=node_id,
                                  init_commands=init_commands,
                                  start_ray_commands=ray_commands,
                                  docker_config=docker_config)

    def spawn_updater(self, node_id, init_commands, ray_start_commands,
                      node_resources, docker_config):
        logger.info(f"Creating new (spawn_updater) updater thread for node"
                    f" {node_id}.")
        updater = NodeUpdaterThread(
            node_id=node_id,
            provider_config=self.config["provider"],
            provider=self.provider,
            auth_config=self.config["auth"],
            cluster_name=self.config["cluster_name"],
            file_mounts=self.config["file_mounts"],
            initialization_commands=with_head_node_ip(
                self._get_node_type_specific_fields(
                    node_id, "initialization_commands")),
            setup_commands=with_head_node_ip(init_commands),
            ray_start_commands=with_head_node_ip(ray_start_commands),
            runtime_hash=self.runtime_hash,
            file_mounts_contents_hash=self.file_mounts_contents_hash,
            is_head_node=False,
            cluster_synced_files=self.config["cluster_synced_files"],
            process_runner=self.process_runner,
            use_internal_ip=True,
            docker_config=docker_config,
            node_resources=node_resources)
        updater.start()
        self.updaters[node_id] = updater

    def can_update(self, node_id):
        if node_id in self.updaters:
            return False
        if not self.launch_config_ok(node_id):
            return False
        if self.num_failed_updates.get(node_id, 0) > 0:  # TODO(ekl) retry?
            return False
        logger.debug(f"{node_id} is not being updated and "
                     "passes config check (can_update=True).")
        return True

    def launch_new_node(self, count: int, node_type: Optional[str]) -> None:
        logger.info(
            "StandardAutoscaler: Queue {} new nodes for launch".format(count))
        self.pending_launches.inc(node_type, count)
        config = copy.deepcopy(self.config)
        self.launch_queue.put((config, count, node_type))

    def all_workers(self):
        return self.workers() + self.unmanaged_workers()

    def workers(self):
        return self.provider.non_terminated_nodes(
            tag_filters={TAG_RAY_NODE_KIND: NODE_KIND_WORKER})

    def unmanaged_workers(self):
        return self.provider.non_terminated_nodes(
            tag_filters={TAG_RAY_NODE_KIND: NODE_KIND_UNMANAGED})

    def log_info_string(self, nodes, target):
        tmp = "Cluster status: "
        tmp += self.info_string(nodes, target)
        tmp += "\n"
        tmp += self.load_metrics.info_string()
        tmp += "\n"
        if self.resource_demand_scheduler:
            tmp += self.resource_demand_scheduler.debug_string(
                nodes, self.pending_launches.breakdown(),
                self.load_metrics.get_resource_utilization())
        if _internal_kv_initialized():
            _internal_kv_put(DEBUG_AUTOSCALING_STATUS, tmp, overwrite=True)
        logger.info(tmp)

    def info_string(self, nodes, target):
        suffix = ""
        if self.pending_launches:
            suffix += " ({} pending)".format(self.pending_launches.value)
        if self.updaters:
            suffix += " ({} updating)".format(len(self.updaters))
        if self.num_failed_updates:
            suffix += " ({} failed to update)".format(
                len(self.num_failed_updates))
        if self.bringup:
            suffix += " (bringup=True)"

        return "{}/{} target nodes{}".format(len(nodes), target, suffix)

    def request_resources(self, resources):
        """Called by monitor to request resources (EXPERIMENTAL).

        Args:
            resources: Either a list of resource bundles or a single resource
                demand dictionary.
        """
        if resources:
            logger.info(
                "StandardAutoscaler: resource_requests={}".format(resources))
        if isinstance(resources, list):
            self.resource_demand_vector = resources
        else:
            for resource, count in resources.items():
                self.resource_requests[resource] = max(
                    self.resource_requests[resource], count)

    def kill_workers(self):
        logger.error("StandardAutoscaler: kill_workers triggered")
        nodes = self.workers()
        if nodes:
            self.provider.terminate_nodes(nodes)
        logger.error("StandardAutoscaler: terminated {} node(s)".format(
            len(nodes)))