Ray
Data & MLRay is an AI compute engine. Ray consists of a core distributed runtime and a set of AI Libraries for accelerating ML workloads.
Release History
View all versions →ray-2.58.017 fixes25 featuresThis release introduces significant enhancements to Ray Serve LLM with KV cache and token-aware routing, and Ray Core with task event offloading. It also brings Databricks DeltaLake integration and a new shuffle v2 backend to Ray Data, alongside experimental Ray Sandbox and expanded TPU support across Ray Train and Core.
ray-2.57.0Breaking33 fixes14 featuresThis release introduces significant improvements to Ray Data with DataSourceV2 enabled by default and Hash Shuffle V2. Ray Serve enhances its HAProxy ingress with a new PyPI package and gRPC support, while Ray Core adds an embedded RocksDB backend for GCS fault tolerance.
ray-2.56.110 fixes2 featuresThis release includes fixes for Ray Data's `to_pandas` regressions, early detection for system-slice memory pressure in Ray Core, and protobuf 7 compatibility with routing fixes for Ray Serve LLM direct streaming.
ray-2.56.0Breaking25 fixes17 featuresThis release focuses heavily on Ray Data stability, introducing features like multi-dataset support, automatic batch sizing, and improved memory management. Ray Serve received significant LLM performance enhancements via re-architecture and new routing policies, while Ray Core introduced GPU-domain-aware placement groups and initial Kubernetes in-place pod resizing support.
ray-2.55.12 fixesThis release focuses on infrastructure maintenance, fixing an SSH connectivity issue in the ray-llm image and upgrading apt packages in the slim base image.
ray-2.55.027 fixes25 featuresThis release introduces the new `DataSourceV2` API, GPU shuffle support, and significant enhancements to Ray Serve including gRPC streaming and HAProxy ingress. Numerous fixes address RCE vulnerabilities, scheduling races, and resource management issues across Ray Data.
ray-2.54.11 fixThis patch release fixes a critical performance degradation issue by temporarily disabling the hanging issue detector which was causing blocking calls to the Ray State API.
ray-2.54.0Breaking30 fixes16 featuresThis release introduces significant new features in Ray Data, including checkpointing, expanded Compute Expressions, and Databricks UC credential support, alongside major enhancements to cluster autoscaling and performance optimizations. Ray Serve gains queue-based autoscaling for TaskConsumers and improved deployment observability.
ray-2.53.0Breaking13 fixes32 featuresThis release adds major new features such as a utilization‑based autoscaler, Kafka datasource, and deployment topology visibility, while dropping Pydantic V1 support and removing deprecated APIs.
ray-2.51.21 fixThis release addresses CVE-2025-62593 by rejecting Sec-Fetch-* and other browser-specific headers in the dashboard's browser rejection logic.
ray-2.52.11 fixSecurity update adds more robust handling for CVE-2025-62593 by checking extra browser-specific headers in dashboard rejection logic.
ray-2.52.0Breaking17 fixes35 featuresRay 2.x introduces token authentication, extensive Iceberg enhancements, new expression capabilities, and numerous performance improvements, while dropping Python 3.9 support and adjusting several defaults that may require migration steps.
ray-2.51.11 featureAdded reuse of previous metadata for identical tensor list transfers using `nixl`.
ray-2.51.0Breaking17 fixes16 featuresThis release introduces Ray Train v2 as the default, adds application‑level autoscaling to Ray Serve, and brings numerous new features and fixes to Ray Data, Train, Tune, and Serve.
ray-2.50.11 fixFixed a deadlock that occurred when cancelling stale requests on in-order actors.
ray-2.50.0Breaking19 fixes32 featuresThis release adds major enhancements across Ray Data, Core, Train, Serve, and RLLib, including a new hash‑based shuffle, expression API, multi‑node LLM support, Direct Transport for GPU data, async inference in Serve, and extensive performance and memory optimizations.
ray-2.49.2There are no functional changes between version 2.49.2 and 2.49.1; this release only increments the patch version for out-of-band reasons.
ray-2.49.12 fixesThis release addresses two bugs: GPU metrics missing in the Ray Dashboard and a regression in Ray Data handling large schemas.
ray-2.49.0Breaking16 fixes33 featuresThis release adds extensive performance enhancements, new features such as JaxTrainer, async inference, and custom autoscaling, while fixing numerous bugs; it also introduces a few breaking changes that may require migration steps.
ray-2.48.0Breaking27 fixes12 featuresThis release adds Delta Lake support, new collective operations, custom request routing, and offline policy evaluation, while also delivering numerous performance improvements and bug fixes across Ray Data, Train, Serve, Tune, and RLlib.
ray-2.47.11 fixRay 2.47.1 resolves a startup failure on macOS.
ray-2.47.0Breaking29 fixes22 featuresThis release adds major LLM serving capabilities, custom routing, and numerous performance and observability improvements across Ray Data, Train, Serve, RLlib, and the Dashboard, while also introducing several breaking changes such as non‑blocking pipelines, stricter Serve name validation, and default uv run integration.
ray-2.46.016 fixes11 featuresRay 2.46 adds hash‑shuffle support for Data, vLLM v1 compatibility for Serve LLM, a new Train Grafana dashboard, and numerous performance and bug‑fix improvements.
ray-2.45.021 fixes13 featuresRay 2.45 adds configurable object store fallback, new cgraph transport options, a ClickHouse sink and several dataset API enhancements, along with numerous stability fixes and an upgraded LightGBM version.
ray-2.44.1There are no functional changes between version 2.44.1 and 2.44.0; this release only increments the patch version for out-of-band reasons.
Common Errors
EngineDeadError3 reportsEngineDeadError in Ray typically arises from a worker process crashing due to resource exhaustion, code errors, or external dependencies. Address this by checking resource limits (CPU, memory, GPU) and increasing them if necessary, thoroughly debugging your code to catch exceptions and prevent crashes, and ensuring any external libraries or services your code relies on are stable and accessible.
ObjectLostError3 reportsObjectLostError usually means a Ray worker node holding an object died, causing the object to be lost from the object store. To fix this, ensure sufficient resources and stability in your Ray cluster to prevent worker node failures. Implement object spilling to disk or object replication across multiple nodes for fault tolerance to persist data even if a worker fails.
OwnerDiedError2 reportsOwnerDiedError typically means an actor or task driver (the object that created the actor/task) died unexpectedly, causing dependent remote objects to become inaccessible. To fix this, ensure the driver script that creates actors and submits tasks remains alive until all ray.get() calls have completed, or implement robust error handling with retries to recover from actor failures and resubmit tasks if needed. Address any underlying instability leading to driver process termination (e.g., out-of-memory errors).
RayActorError2 reportsRayActorError usually indicates that an actor has failed due to an exception during its initialization or execution of a task, often due to resource exhaustion (OOM) or other unhandled errors. To fix it, implement robust error handling within the actor's methods using try-except blocks to catch exceptions and potentially retry failed operations or gracefully terminate. Also, ensure sufficient resources are allocated to the actor to prevent resource exhaustion, and configure appropriate retry policies or circuit breakers to handle transient failures.
InternalServerError2 reportsThis error typically occurs in ray. Check the example issues for common solutions.
ActorUnschedulableError2 reportsRelated Data & ML Packages
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