Changelog

Refer to the 2.15 Upgrade Guide for backwards compatibility notes with 2.14.x. This release also contains all changes up to and including v2.14.7.

Go Version

• 1.27.1 (#8551)

Added

JetStream

• Desired state metalayer (#8432, #8437, #8439, #8443, #8452, #8460, #8476, #8576, #8598, #8602, #8603) • A new desired state reconciliation engine for streams and consumers considerably improves the safety and reliability of asset moves and scales • Updating the placement or replication factor midway through an existing scale/move operation, cancelling an in-flight scale/move, or peer-removing is now much safer • ADR：https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-62.md • Cancel stream move endpoint (#8476) • An in-flight scale/move operation on a stream can be cancelled and the asset returned to its original placement using the new $JS.API.STREAM.CANCEL_MOVE endpoint • ADR：https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-62.md • Evacuate endpoints (#8443) • The new $JS.API.SERVER.EVACUATE endpoint can safely evacuate streams, and any consumers on those streams, from a node • The new $JS.API.STREAM.PEER.EVACUATE.* endpoint can safely evacuate a peer, and any consumers on that peer, from a stream • These operations combined allow for maintenance operations with full transfer of data and state without having to peer-remove first • ADR：https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-62.md • Metalayer rescue for disaster recovery (#8408) • The new $JS.API.META.RESCUE endpoint can temporarily lower the quorum-needed for the metalayer, in order to facilitate the recovery of a system where nodes have been permanently lost and the metalayer cannot reach quorum • ADR：https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-61.md • Stream backup and restore v2 (#7882, #8584, #8591, #8604) • A new backup format for stream snapshots which reads out per-message rather than per-block • The new backup format also now correctly includes non-replicated consumers on follower nodes • ADR：https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-63.md • Detect source stream recreation (#8384) • The server now detects a source stream being recreated, restarting the sourcing back from the beginning, ensuring new messages are sourced • Stream source indexing (#8282, #8516, #8283) • Restarts and leader changes previously required expensive backward scans through the stream to find the last sourced indices. These are now persisted in an index for instant lookup. • Domain-prefixed JS API in system account (#8429) • When a system account is bridged between the hub and a leaf node, the domain-prefixed JS API can now be used to operate on the leaf node while directly connected to the hub

Changed

JetStream

• Streams now have a default limit of 1000 consumers, unless max_consumers is specified in the stream config or account limits (#8337, #8566) • Applications planning to use a large number of consumers on a stream should configure max_consumers in the stream config or account limits to an appropriately high number • The server-wide default of 1000 can be overridden by setting default_max_consumers in the JetStream limits, or can be disabled by setting to -1 • This limit does not affect existing consumers and will not result in consumer deletions, only the creation of new consumers is prevented • Sync changes for replicated streams (#8447) • When the sync_interval is set to always, replicated streams now sync their WAL entries but no longer sync upper stream layer writes • The synced log allows the stream to recover safely, but removing unnecessary syncs from the upper stream layer dramatically improves performance • Non-replicated R1 streams are not affected by this change and will continue to sync at the stream layer as normal • The js_raft_delete_range feature is now enabled by default (#8520)

Leafnodes

• The no_advertise option no longer includes the hub's own listener address (#8451, contributed by @freakes)

Improved

JetStream

• Shorter wait for durable source/mirror consumer resets (#8323) • When using durable consumers for sourcing or mirroring, the heartbeats now short-circuit the recreation backoff • An atomic batch for a single-replica stream run with sync：always now syncs messages as a group (#8539, contributed by @RainyPixel) • JetStream source/mirror reply subjects can now opt-in to be domain/account aware (#8586, contributed by @ayushk-1801)

MQTT

• QOS 1 published into JetStream are pipelined for increased throughput (#8415, contributed by @levb)

Fixed

Leafnodes

• Leafnode isolation using request_isolation, or with hub-enforced isolate, now works correctly across cluster nodes (#8504)

Complete Changes

https://github.com/nats-io/nats-server/compare/v2.14.7...v2.15.0