Merge remote-tracking branch 'upstream/main' into test_no_overlap_ccs…

…_ccr

.buildkite/pipelines/intake.yml

@@ -56,7 +56,7 @@ steps:
         timeout_in_minutes: 300
         matrix:
           setup:
-            BWC_VERSION: ["7.17.22", "8.13.4", "8.14.0", "8.15.0"]
+            BWC_VERSION: ["7.17.22", "8.13.5", "8.14.0", "8.15.0"]
         agents:
           provider: gcp
           image: family/elasticsearch-ubuntu-2004

.buildkite/pipelines/periodic-packaging.yml

@@ -529,8 +529,8 @@ steps:
         env:
           BWC_VERSION: 8.12.2
 
-      - label: "{{matrix.image}} / 8.13.4 / packaging-tests-upgrade"
-        command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.13.4
+      - label: "{{matrix.image}} / 8.13.5 / packaging-tests-upgrade"
+        command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.13.5
         timeout_in_minutes: 300
         matrix:
           setup:
@@ -543,7 +543,7 @@ steps:
           machineType: custom-16-32768
           buildDirectory: /dev/shm/bk
         env:
-          BWC_VERSION: 8.13.4
+          BWC_VERSION: 8.13.5
 
       - label: "{{matrix.image}} / 8.14.0 / packaging-tests-upgrade"
         command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.14.0

.buildkite/pipelines/periodic.yml

@@ -591,8 +591,8 @@ steps:
             - signal_reason: agent_stop
               limit: 3
 
-      - label: 8.13.4 / bwc
-        command: .ci/scripts/run-gradle.sh -Dbwc.checkout.align=true v8.13.4#bwcTest
+      - label: 8.13.5 / bwc
+        command: .ci/scripts/run-gradle.sh -Dbwc.checkout.align=true v8.13.5#bwcTest
         timeout_in_minutes: 300
         agents:
           provider: gcp
@@ -601,7 +601,7 @@ steps:
           buildDirectory: /dev/shm/bk
           preemptible: true
         env:
-          BWC_VERSION: 8.13.4
+          BWC_VERSION: 8.13.5
         retry:
           automatic:
             - exit_status: "-1"
@@ -714,7 +714,7 @@ steps:
           setup:
             ES_RUNTIME_JAVA:
               - openjdk17
-            BWC_VERSION: ["7.17.22", "8.13.4", "8.14.0", "8.15.0"]
+            BWC_VERSION: ["7.17.22", "8.13.5", "8.14.0", "8.15.0"]
         agents:
           provider: gcp
           image: family/elasticsearch-ubuntu-2004
@@ -760,7 +760,7 @@ steps:
               - openjdk17
               - openjdk21
               - openjdk22
-            BWC_VERSION: ["7.17.22", "8.13.4", "8.14.0", "8.15.0"]
+            BWC_VERSION: ["7.17.22", "8.13.5", "8.14.0", "8.15.0"]
         agents:
           provider: gcp
           image: family/elasticsearch-ubuntu-2004

.ci/bwcVersions

@@ -30,6 +30,6 @@ BWC_VERSION:
   - "8.10.4"
   - "8.11.4"
   - "8.12.2"
-  - "8.13.4"
+  - "8.13.5"
   - "8.14.0"
   - "8.15.0"

.ci/snapshotBwcVersions

@@ -1,5 +1,5 @@
 BWC_VERSION:
   - "7.17.22"
-  - "8.13.4"
+  - "8.13.5"
   - "8.14.0"
   - "8.15.0"

distribution/packages/src/deb/lintian/elasticsearch

@@ -59,3 +59,7 @@ unknown-field License
 # don't build them ourselves and the license precludes us modifying them
 # to fix this.
 library-not-linked-against-libc usr/share/elasticsearch/modules/x-pack-ml/platform/linux-x86_64/lib/libmkl_*.so
+
+# shared-lib-without-dependency-information (now shared-library-lacks-prerequisites) is falsely reported for libvec.so
+# which has no dependencies (not even libc) besides the symbols in the base executable.
+shared-lib-without-dependency-information usr/share/elasticsearch/lib/platform/linux-x64/libvec.so

docs/changelog/108088.yaml

@@ -0,0 +1,5 @@
+pr: 108088
+summary: Add a SIMD (AVX2) optimised vector distance function for int7 on x64
+area: "Search"
+type: enhancement
+issues: []

docs/changelog/108410.yaml

@@ -0,0 +1,5 @@
+pr: 108410
+summary: GeoIP tasks should wait longer for master
+area: Ingest Node
+type: bug
+issues: []

docs/changelog/108452.yaml

@@ -0,0 +1,5 @@
+pr: 108452
+summary: Add the rerank task to the Elasticsearch internal inference service
+area: Machine Learning
+type: enhancement
+issues: []

docs/changelog/108459.yaml

@@ -0,0 +1,6 @@
+pr: 108459
+summary: Do not use global ordinals strategy if the leaf reader context cannot be
+  obtained
+area: Machine Learning
+type: bug
+issues: []

docs/changelog/108517.yaml

@@ -0,0 +1,6 @@
+pr: 108517
+summary: Forward `indexServiceSafe` exception to listener
+area: Transform
+type: bug
+issues:
+ - 108418

docs/changelog/108518.yaml

@@ -0,0 +1,5 @@
+pr: 108518
+summary: Remove leading is_ prefix from Enterprise geoip docs
+area: Ingest Node
+type: bug
+issues: []

docs/changelog/108521.yaml

@@ -0,0 +1,6 @@
+pr: 108521
+summary: Adding override for lintian false positive on `libvec.so`
+area: "Packaging"
+type: bug
+issues:
+ - 108514

docs/changelog/108522.yaml

@@ -0,0 +1,5 @@
+pr: 108522
+summary: Ensure we return non-negative scores when scoring scalar dot-products
+area: Vector Search
+type: bug
+issues: []

docs/changelog/108562.yaml

@@ -0,0 +1,6 @@
+pr: 108562
+summary: Add `internalClusterTest` for and fix leak in `ExpandSearchPhase`
+area: Search
+type: bug
+issues:
+ - 108369

docs/internal/DistributedArchitectureGuide.md

@@ -1,6 +1,14 @@
-# Distributed Area Team Internals
+# Distributed Area Internals
 
-(Summary, brief discussion of our features)
+The Distributed Area contains indexing and coordination systems.
+
+The index path stretches from the user REST command through shard routing down to each individual shard's translog and storage
+engine. Reindexing is effectively reading from a source index and writing to a destination index (perhaps on different nodes).
+The coordination side includes cluster coordination, shard allocation, cluster autoscaling stats, task management, and cross
+cluster replication. Less obvious coordination systems include networking, the discovery plugin system, the snapshot/restore
+logic, and shard recovery.
+
+A guide to the general Elasticsearch components can be found [here](https://github.com/elastic/elasticsearch/blob/main/docs/internal/GeneralArchitectureGuide.md).
 
 # Networking
 
@@ -237,9 +245,101 @@ works in parallel with the storage engine.)
 
 # Autoscaling
 
-(Reactive and proactive autoscaling. Explain that we surface recommendations, how control plane uses it.)
-
-(Sketch / list the different deciders that we have, and then also how we use information from each to make a recommendation.)
+The Autoscaling API in ES (Elasticsearch) uses cluster and node level statistics to provide a recommendation
+for a cluster size to support the current cluster data and active workloads. ES Autoscaling is paired
+with an ES Cloud service that periodically polls the ES elected master node for suggested cluster
+changes. The cloud service will add more resources to the cluster based on Elasticsearch's recommendation.
+Elasticsearch by itself cannot automatically scale.
+
+Autoscaling recommendations are tailored for the user [based on user defined policies][], composed of data
+roles (hot, frozen, etc) and [deciders][]. There's a public [webinar on autoscaling][], as well as the
+public [Autoscaling APIs] docs.
+
+Autoscaling's current implementation is based primary on storage requirements, as well as memory capacity
+for ML and frozen tier. It does not yet support scaling related to search load. Paired with ES Cloud,
+autoscaling only scales upward, not downward, except for ML nodes that do get scaled up _and_ down.
+
+[based on user defined policies]: https://www.elastic.co/guide/en/elasticsearch/reference/current/xpack-autoscaling.html
+[deciders]: https://www.elastic.co/guide/en/elasticsearch/reference/current/autoscaling-deciders.html
+[webinar on autoscaling]: https://www.elastic.co/webinars/autoscaling-from-zero-to-production-seamlessly
+[Autoscaling APIs]: https://www.elastic.co/guide/en/elasticsearch/reference/current/autoscaling-apis.html
+
+### Plugin REST and TransportAction entrypoints
+
+Autoscaling is a [plugin][]. All the REST APIs can be found in [autoscaling/rest/][].
+`GetAutoscalingCapacityAction` is the capacity calculation operation REST endpoint, as opposed to the
+other rest commands that get/set/delete the policies guiding the capacity calculation. The Transport
+Actions can be found in [autoscaling/action/], where [TransportGetAutoscalingCapacityAction][] is the
+entrypoint on the master node for calculating the optimal cluster resources based on the autoscaling
+policies.
+
+[plugin]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/Autoscaling.java#L72
+[autoscaling/rest/]: https://github.com/elastic/elasticsearch/tree/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/rest
+[autoscaling/action/]: https://github.com/elastic/elasticsearch/tree/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action
+[TransportGetAutoscalingCapacityAction]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action/TransportGetAutoscalingCapacityAction.java#L82-L98
+
+### How cluster capacity is determined
+
+[AutoscalingMetadata][] implements [Metadata.Custom][] in order to persist autoscaling policies. Each
+Decider is an implementation of [AutoscalingDeciderService][]. The [AutoscalingCalculateCapacityService][]
+is responsible for running the calculation.
+
+[TransportGetAutoscalingCapacityAction.computeCapacity] is the entry point to [AutoscalingCalculateCapacityService.calculate],
+which creates a [AutoscalingDeciderResults][] for [each autoscaling policy][]. [AutoscalingDeciderResults.toXContent][] then
+determines the [maximum required capacity][] to return to the caller. [AutoscalingCapacity][] is the base unit of a cluster
+resources recommendation.
+
+The `TransportGetAutoscalingCapacityAction` response is cached to prevent concurrent callers
+overloading the system: the operation is expensive. `TransportGetAutoscalingCapacityAction` contains
+a [CapacityResponseCache][]. `TransportGetAutoscalingCapacityAction.masterOperation`
+calls [through the CapacityResponseCache][], into the `AutoscalingCalculateCapacityService`, to handle
+concurrent callers.
+
+[AutoscalingMetadata]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/AutoscalingMetadata.java#L38
+[Metadata.Custom]: https://github.com/elastic/elasticsearch/blob/v8.13.2/server/src/main/java/org/elasticsearch/cluster/metadata/Metadata.java#L141-L145
+[AutoscalingDeciderService]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingDeciderService.java#L16-L19
+[AutoscalingCalculateCapacityService]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingCalculateCapacityService.java#L43
+
+[TransportGetAutoscalingCapacityAction.computeCapacity]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action/TransportGetAutoscalingCapacityAction.java#L102-L108
+[AutoscalingCalculateCapacityService.calculate]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingCalculateCapacityService.java#L108-L139
+[AutoscalingDeciderResults]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingDeciderResults.java#L34-L38
+[each autoscaling policy]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingCalculateCapacityService.java#L124-L131
+[AutoscalingDeciderResults.toXContent]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingDeciderResults.java#L78
+[maximum required capacity]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingDeciderResults.java#L105-L116
+[AutoscalingCapacity]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingCapacity.java#L27-L35
+
+[CapacityResponseCache]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action/TransportGetAutoscalingCapacityAction.java#L44-L47
+[through the CapacityResponseCache]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action/TransportGetAutoscalingCapacityAction.java#L97
+
+### Where the data comes from
+
+The Deciders each pull data from different sources as needed to inform their decisions. The
+[DiskThresholdMonitor][] is one such data source. The Monitor runs on the master node and maintains
+lists of nodes that exceed various disk size thresholds. [DiskThresholdSettings][] contains the
+threshold settings with which the `DiskThresholdMonitor` runs.
+
+[DiskThresholdMonitor]: https://github.com/elastic/elasticsearch/blob/v8.13.2/server/src/main/java/org/elasticsearch/cluster/routing/allocation/DiskThresholdMonitor.java#L53-L58
+[DiskThresholdSettings]: https://github.com/elastic/elasticsearch/blob/v8.13.2/server/src/main/java/org/elasticsearch/cluster/routing/allocation/DiskThresholdSettings.java#L24-L27
+
+### Deciders
+
+The `ReactiveStorageDeciderService` tracks information that demonstrates storage limitations are causing
+problems in the cluster. It uses [an algorithm defined here][]. Some examples are
+- information from the `DiskThresholdMonitor` to find out whether nodes are exceeding their storage capacity
+- number of unassigned shards that failed allocation because of insufficient storage
+- the max shard size and minimum node size, and whether these can be satisfied with the existing infrastructure
+
+[an algorithm defined here]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/storage/ReactiveStorageDeciderService.java#L158-L176
+
+The `ProactiveStorageDeciderService` maintains a forecast window that [defaults to 30 minutes][]. It only
+runs on data streams (ILM, rollover, etc), not regular indexes. It looks at past [index changes][] that
+took place within the forecast window to [predict][] resources that will be needed shortly.
+
+[defaults to 30 minutes]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/storage/ProactiveStorageDeciderService.java#L32
+[index changes]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/storage/ProactiveStorageDeciderService.java#L79-L83
+[predict]: https://github.com/elastic/elasticsearch/blob/v8.13.2/x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/storage/ProactiveStorageDeciderService.java#L85-L95
+
+There are several more Decider Services, implementing the `AutoscalingDeciderService` interface.
 
 # Snapshot / Restore