[meta] 6.8 release

[codebrain]

Leftover Work

Geo:

• Integrate Lucene's LatLonShape (BKD Backed GeoShapes) as default geo_shape indexing approach [Geo] Integrate Lucene's LatLonShape (BKD Backed GeoShapes) as default geo_shape indexing approach elasticsearch#35320 (issue: BKD-based geo shapes elasticsearch#32039) - Set obsolete warning on GeoShape properties. #3770

Cross-cluster replication

• Refactor AutoFollowCoordinator to track leader indices per remote cluster #36031 (issues: #33007, #35895) - no client changes required
• Refactor auto follow coordinator #35895 (issue: #33007) - no client changes required

The last two removed CCR_AUTO_FOLLOW_POLL_INTERVAL which i think is returned on the ccr stats API's (investigate)

CRUD

• Rename seq# powered optimistic concurrency control parameters to ifSeqNo/ifPrimaryTerm #36757 (issues: #10708, #36148) - no client changes needed, API generator picked up new parameters
• Expose Sequence Number based Optimistic Concurrency Control in the rest layer #36721 (issues: #10708, #36148) - no client changes needed, API generator picked up new parameters
• Add doc’s sequence number + primary term to GetResult and use it for updates #36680 (issues: #10708, #36148) - Add doc’s sequence number + primary term to get responses #3767

Distributed

• Add global and index level blocks to IndexSettings #35695 (issues: #35332, #35597) - no client changes required

Machine Learning

• Enable the use of endpoints starting with _ml instead of _xpack/ml #36373 (issue: #36315) - no client changes required
• Add support for rollup indexes in datafeeds #34654 - no client changes required

(First is not actionable on our end in 6.x).

Rollup

• Add non-X-Pack centric rollup endpoints #36383 (issues: #35958, #35962) - no client changes required
• Add more diagnostic stats to job #35471 - Additional Rollup Stats #3759
• Add default fields to job configs #34831 - no client changes required
• Add wait_for_completion option to StopRollupJob API #34811 (issue: #34574) - no client changes required, was picked up in an API regen

Search

• Warn when using use_dis_max in multi_match #36614 (issue: #36488) - no client changes required
• Extend field caps API to mark meta fields #36309 - original issue was closed

Security

• Make credentials mandatory when launching xpack/migrate #36197 (issues: #29847, #33972) - no client changes required
• Make credentials mandatory when launching x-pack/migrate #33972 (issue: #29847) - no client changes required

SQL

• Move requests' parameters to requests JSON body #36149 (issue: #35992) - no client changes needed
• XPack FeatureSet functionality #35725 (issue: #34821) - XPack info and usage improvements. #3764

Stats

• Handle OS pretty name on old OS without OS release #35453 (issue: #35440)
• Add more detailed OS name on Linux #35352 - Add pretty names (and other properties) to the cluster stats response. #3766

Bug fixes

Aggregations::

• Preserve format when aggregation contains unmapped date fields [#35254] (issue: [#31760]) - reminds me of a ticket we once raised (will follow up to figure if they are related) - no client changes needed, this is a server-side change

Cross-cluster replication::

• Resume follow Api should not require a request body [#37217] (issue: [#37022]) (_breaking change we need a patch for) - change was implemented on 10th Jan, but CCR was implement in client on 25th Jan, therefore no client changes needed as already incorporated.
• Report error if auto follower tries auto follow a leader index with soft deletes disabled [#36886] (issue: [#33007]) - no client changes needed
• Fix the names of CCR stats endpoints in usage API [#35438] - no client changes needed

Index lifecycle management::

• Remove indexing_complete when removing policy [#36620] - no client changes needed

Index APIs::

• Make XContentBuilder in AliasActions build is_write_index field [#35071] - no client changes needed
• Raise a 404 exception when document source is not found (#33384) [#34083] (issue: [#33384]) - no client changes needed

Ingest::

• Support default pipelines + bulk upserts [#36618] (issue: [#36219]) - no client changes needed
• Support default pipeline through an alias [#36231] (issue: [#35817]) - no client changes needed

Network::

• Do not resolve addresses in remote connection info [#36671] (issue: [#35658]) - no client changes needed
• Always compress based on the settings [#36522] (issue: [#36399]) - no client changes needed
• http.publish_host should contain CNAME [#32806] (issue: [#22029]) - no client changes needed

Scripting::

• Fix serialization bug in painless execute api request [#36075] (issue: [#36050]) - no client changes needed

[codebrain]

Relates to: #3774