Improve unschedulable task warning messages by integrating with the autoscaler

python/ray/autoscaler/_private/autoscaler.py

@@ -1,5 +1,6 @@
 from collections import defaultdict, namedtuple, Counter
-from typing import Callable, Any, Optional, Dict, List, Set, FrozenSet, Tuple
+from typing import Any, Optional, Dict, List, Set, FrozenSet, Tuple, Union, \
+    Callable
 import copy
 import logging
 import math
@@ -83,7 +84,7 @@ class StandardAutoscaler:
 
     def __init__(
             self,
-            config_path: str,
+            config_reader: Union[str, Callable[[], dict]],
             load_metrics: LoadMetrics,
             max_launch_batch: int = AUTOSCALER_MAX_LAUNCH_BATCH,
             max_concurrent_launches: int = AUTOSCALER_MAX_CONCURRENT_LAUNCHES,
@@ -96,22 +97,33 @@ def __init__(
         """Create a StandardAutoscaler.
 
         Args:
-        config_path: Path to a Ray Autoscaler YAML.
-        load_metrics: Provides metrics for the Ray cluster.
-        max_launch_batch: Max number of nodes to launch in one request.
-        max_concurrent_launches: Max number of nodes that can be concurrently
-            launched. This value and `max_launch_batch` determine the number
-            of batches that are used to launch nodes.
-        max_failures: Number of failures that the autoscaler will tolerate
-            before exiting.
-        process_runner: Subprocess-like interface used by the CommandRunner.
-        update_interval_s: Seconds between running the autoscaling loop.
-        prefix_cluster_info: Whether to add the cluster name to info strings.
-        event_summarizer: Utility to consolidate duplicated messages.
-        prom_metrics: Prometheus metrics for autoscaler-related operations.
+            config_reader: Path to a Ray Autoscaler YAML, or a function to read
+                and return the latest config.
+            load_metrics: Provides metrics for the Ray cluster.
+            max_launch_batch: Max number of nodes to launch in one request.
+            max_concurrent_launches: Max number of nodes that can be
+                concurrently launched. This value and `max_launch_batch`
+                determine the number of batches that are used to launch nodes.
+            max_failures: Number of failures that the autoscaler will tolerate
+                before exiting.
+            process_runner: Subproc-like interface used by the CommandRunner.
+            update_interval_s: Seconds between running the autoscaling loop.
+            prefix_cluster_info: Whether to add the cluster name to info strs.
+            event_summarizer: Utility to consolidate duplicated messages.
+            prom_metrics: Prometheus metrics for autoscaler-related operations.
         """
 
-        self.config_path = config_path
+        if isinstance(config_reader, str):
+            # Auto wrap with file reader.
+            def read_fn():
+                with open(config_reader) as f:
+                    new_config = yaml.safe_load(f.read())
+                return new_config
+
+            self.config_reader = read_fn
+        else:
+            self.config_reader = config_reader
+
         # Prefix each line of info string with cluster name if True
         self.prefix_cluster_info = prefix_cluster_info
         # Keep this before self.reset (self.provider needs to be created
@@ -218,17 +230,31 @@ def _update(self):
             self.provider.internal_ip(node_id) for node_id in self.all_workers
         ])
 
-        self.terminate_nodes_to_enforce_config_constraints(now)
-
-        self.launch_required_nodes()
-
-        if self.disable_node_updaters:
-            self.terminate_unhealthy_nodes(now)
-        else:
-            self.process_completed_updates()
-            self.update_nodes()
-            self.attempt_to_recover_unhealthy_nodes(now)
-            self.set_prometheus_updater_data()
+        if not self.provider.is_readonly():
+            self.terminate_nodes_to_enforce_config_constraints(now)
+
+        to_launch, unfulfilled = (
+            self.resource_demand_scheduler.get_nodes_to_launch(
+                self.provider.non_terminated_nodes(tag_filters={}),
+                self.pending_launches.breakdown(),
+                self.load_metrics.get_resource_demand_vector(),
+                self.load_metrics.get_resource_utilization(),
+                self.load_metrics.get_pending_placement_groups(),
+                self.load_metrics.get_static_node_resources_by_ip(),
+                ensure_min_cluster_size=self.load_metrics.
+                get_resource_requests()))
+        self._report_pending_infeasible(unfulfilled)
+
+        if not self.provider.is_readonly():
+            self.launch_required_nodes(to_launch)
+
+            if self.disable_node_updaters:
+                self.terminate_unhealthy_nodes(now)
+            else:
+                self.process_completed_updates()
+                self.update_nodes()
+                self.attempt_to_recover_unhealthy_nodes(now)
+                self.set_prometheus_updater_data()
 
         logger.info(self.info_string())
         legacy_log_info_string(self, self.workers)
@@ -354,15 +380,7 @@ def terminate_scheduled_nodes(self):
         self.nodes_to_terminate = []
         self.update_worker_list()
 
-    def launch_required_nodes(self):
-        to_launch = self.resource_demand_scheduler.get_nodes_to_launch(
-            self.provider.non_terminated_nodes(tag_filters={}),
-            self.pending_launches.breakdown(),
-            self.load_metrics.get_resource_demand_vector(),
-            self.load_metrics.get_resource_utilization(),
-            self.load_metrics.get_pending_placement_groups(),
-            self.load_metrics.get_static_node_resources_by_ip(),
-            ensure_min_cluster_size=self.load_metrics.get_resource_requests())
+    def launch_required_nodes(self, to_launch):
         if to_launch:
             for node_type, count in to_launch.items():
                 self.launch_new_node(count, node_type=node_type)
@@ -452,6 +470,38 @@ def set_prometheus_updater_data(self):
                 num_recovering += 1
         self.prom_metrics.recovering_nodes.set(num_recovering)
 
+    def _report_pending_infeasible(self, resources: List[ResourceDict]):
+        """Emit event messages for infeasible or unschedulable tasks."""
+        pending = []
+        infeasible = []
+        for bundle in resources:
+            placement_group = any("_group_" in k for k in bundle)
+            if placement_group:
+                continue
+            if self.resource_demand_scheduler.is_feasible(bundle):
+                pending.append(bundle)
+            else:
+                infeasible.append(bundle)
+        if pending:
+            if self.load_metrics.cluster_full_reported:
+                for request in pending:
+                    self.event_summarizer.add_once_per_interval(
+                        "Warning: The following resource request cannot be "
+                        "scheduled right now: {}. This is likely due to all "
+                        "cluster resources being claimed by actors. Consider "
+                        "creating fewer actors or adding more nodes "
+                        "to this Ray cluster.".format(request),
+                        key="pending_{}".format(sorted(request.items())),
+                        interval_s=30)
+        if infeasible:
+            for request in infeasible:
+                self.event_summarizer.add_once_per_interval(
+                    "Error: No available node types can fulfill resource "
+                    "request {}. Add suitable node types to this cluster to "
+                    "resolve this issue.".format(request),
+                    key="infeasible_{}".format(sorted(request.items())),
+                    interval_s=30)
+
     def _sort_based_on_last_used(self, nodes: List[NodeID],
                                  last_used: Dict[str, float]) -> List[NodeID]:
         """Sort the nodes based on the last time they were used.
@@ -615,8 +665,7 @@ def reset(self, errors_fatal=False):
             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())
+            new_config = self.config_reader()
             if new_config != getattr(self, "config", None):
                 try:
                     validate_config(new_config)

python/ray/autoscaler/_private/commands.py

@@ -55,8 +55,7 @@
 import ray.autoscaler._private.subprocess_output_util as cmd_output_util
 from ray.autoscaler._private.load_metrics import LoadMetricsSummary
 from ray.autoscaler._private.autoscaler import AutoscalerSummary
-from ray.autoscaler._private.util import format_info_string, \
-    format_info_string_no_node_types
+from ray.autoscaler._private.util import format_info_string
 
 logger = logging.getLogger(__name__)
 
@@ -109,13 +108,8 @@ def debug_status(status, error) -> str:
         as_dict = json.loads(status)
         time = datetime.datetime.fromtimestamp(as_dict["time"])
         lm_summary = LoadMetricsSummary(**as_dict["load_metrics_report"])
-        if "autoscaler_report" in as_dict:
-            autoscaler_summary = AutoscalerSummary(
-                **as_dict["autoscaler_report"])
-            status = format_info_string(
-                lm_summary, autoscaler_summary, time=time)
-        else:
-            status = format_info_string_no_node_types(lm_summary, time=time)
+        autoscaler_summary = AutoscalerSummary(**as_dict["autoscaler_report"])
+        status = format_info_string(lm_summary, autoscaler_summary, time=time)
     if error:
         status += "\n"
         status += error.decode("utf-8")

python/ray/autoscaler/_private/constants.py

@@ -18,7 +18,7 @@ def env_integer(key, default):
 
 
 # Whether event logging to driver is enabled. Set to 0 to disable.
-AUTOSCALER_EVENTS = env_integer("AUTOSCALER_EVENTS", 1)
+AUTOSCALER_EVENTS = env_integer("RAY_SCHEDULER_EVENTS", 1)
 
 # Whether to avoid launching GPU nodes for CPU only tasks.
 AUTOSCALER_CONSERVE_GPU_NODES = env_integer("AUTOSCALER_CONSERVE_GPU_NODES", 1)

python/ray/autoscaler/_private/event_summarizer.py

@@ -1,11 +1,14 @@
 from typing import Any, Callable, Dict, List
+import time
 
 
 class EventSummarizer:
     """Utility that aggregates related log messages to reduce log spam."""
 
     def __init__(self):
         self.events_by_key: Dict[str, int] = {}
+        self.messages: List[str] = []
+        self.key_ttl: Dict[str, float] = {}
 
     def add(self, template: str, *, quantity: Any,
             aggregate: Callable[[Any, Any], Any]) -> None:
@@ -27,13 +30,30 @@ def add(self, template: str, *, quantity: Any,
         else:
             self.events_by_key[template] = quantity
 
+    def add_once_per_interval(self, message: str, key: str, interval_s: int):
+        """Add a log message, which is throttled once per interval by a key.
+
+        Args:
+            message (str): The message to log.
+            key (str): The key to use to deduplicate the message.
+            interval_s (int): Throttling interval in seconds.
+        """
+        if key not in self.key_ttl:
+            self.key_ttl[key] = time.time() + interval_s
+            self.messages.append(message)
+
     def summary(self) -> List[str]:
         """Generate the aggregated log summary of all added events."""
         out = []
         for template, quantity in self.events_by_key.items():
             out.append(template.format(quantity))
+        out.extend(self.messages)
         return out
 
     def clear(self) -> None:
         """Clear the events added."""
         self.events_by_key.clear()
+        self.messages.clear()
+        for k, t in list(self.key_ttl.items()):
+            if time.time() > t:
+                del self.key_ttl[k]

python/ray/autoscaler/_private/load_metrics.py

@@ -83,6 +83,7 @@ def __init__(self, local_ip=None):
         self.infeasible_bundles = []
         self.pending_placement_groups = []
         self.resource_requests = []
+        self.cluster_full_reported = False
 
     def update(self,
                ip: str,
@@ -91,9 +92,11 @@ def update(self,
                resource_load: Dict[str, Dict],
                waiting_bundles: List[Dict[str, float]] = None,
                infeasible_bundles: List[Dict[str, float]] = None,
-               pending_placement_groups: List[PlacementGroupTableData] = None):
+               pending_placement_groups: List[PlacementGroupTableData] = None,
+               cluster_full_reported: bool = False):
         self.resource_load_by_ip[ip] = resource_load
         self.static_resources_by_ip[ip] = static_resources
+        self.cluster_full_reported = cluster_full_reported
 
         if not waiting_bundles:
             waiting_bundles = []