After this series, tablet replication can handle the scenario of bootstrapping new nodes. The ownership is distributed indirectly by the means of a load-balancer which moves tablets around in the background. See docs/dev/topology-over-raft.md for details.
The implementation is by no means meant to be perfect, especially in terms of performance, and will be improved incrementally.
The load balancer will be also kicked by schema changes, so that allocation/deallocation done during table creation/drop will be rebalanced.
Tablet data is streamed using existing `range_streamer`, which is the infrastructure for "the old streaming". This will be later replaced by sstable transfer once integration of tablets with compaction groups is finished. Also, cleanup is not wired yet, also blocked by compaction group integration.
Closes#14601
* github.com:scylladb/scylladb:
tests: test_tablets: Add test for bootstraping a node
storage_service: topology_coordinator: Implement tablet migration state machine
tablets: Introduce tablet_mutation_builder
service: tablet_allocator: Introduce tablet load balancer
tablets: Introduce tablet_map::for_each_tablet()
topology: Introduce get_node()
token_metadata: Add non-const getter of tablet_metadata
storage_service: Notify topology state machine after applying schema change
storage_service: Implement stream_tablet RPC
tablets: Introduce global_tablet_id
stream_transfer_task, multishard_writer: Work with table sharder
tablets: Turn tablet_id into a struct
db: Do not create per-keyspace erm for tablet-based tables
tablets: effective_replication_map: Take transition stage into account when computing replicas
tablets: Store "stage" in transition info
doc: Document tablet migration state machine and load balancer
locator: erm: Make get_endpoints_for_reading() always return read replicas
storage_service: topology_coordinator: Sleep on failure between retries
storage_service: topology_coordinator: Simplify coordinator loop
main: Require experimental raft to enable tablets
ff1f461a42