Tracking issue for Region Migration

[WenyXu]

What problem does the new feature solve?

As mentioned in #1622, Region Migration moves the region between Datanodes.

What does the feature do?

RFC

• RFC document docs: add region migration RFC #2703

Meat Server

• feat: implement region migration manager #3014
• HTTP API
  • feat: implement param parsing of SubmitRegionMigrationTaskHandler #3015
  • feat: expose region migration http endpoint #3032
• Upgrade the Follower Region to the Leader Role.
  • refactor: refactor region lease keeper #2704
  • refactor: heartbeat response contains region role #2718
• Set the downgraded flag before deactivating a Region.
  • feat: add leader_status for RegionRoute #2670
• Remove the Inactive Region Manager.
  • feat: downgrade failed region before closing #2715
  • refactor: replace InactiveRegionManager with RegionLeaseKeeper #2729
• Enable new Region Lease Keeper.
  • feat: introduce the region lease keeper #2645
• Migration Procedure.
  • feat: add region migration procedure skeleton #2743
  • feat: grant lease to opening regions #2752
  • feat: add migration start step #2756
  • feat: add open candidate region step #2757
  • feat: add update metadata step for downgrading leader region #2771
  • feat: add downgrade leader region step #2792
  • feat: add update metadata step for upgrading candidate region #2811
  • feat: add update metadata step for rollbacking downgraded region #2812
  • feat: add upgrade candidate region step #2829

Datanode

• Report Region Role. feat: introduce the region role #2640
• feat: handle the downgrade region instruction #2855
• feat: add skip_wal_replay to OpenRegion instruction #2977
• feat(mito): add skip_wal_replay option to OpenRegionRequest #2955
• feat: add CatchupRequest to engine #2939
• feat: implement handle upgrade region instruction #3013

Tests

• test: add tests for region migration procedure #2857
• test: add more tests for region migration procedure #2895
• feat(tests-integration): add a naive region migration integration test #3078

Others

• refactor: unify the injection of WAL option #3066
• feat: abort region migration if leader region peer is unexpected #3086
• refactor: allow procedure to acquire share lock #3061
• feat: add logs for upgrading candidate region and updating metadata #3077
• feat(tests-integration): add more region migration integration tests #3094

Implementation challenges

No response