Currently he gossiper marks endpoint_state objects as alive/dead.
I some cases the endpoint_state::is_alive function is checked but in many other cases
gossiper::is_alive(endpoint) is used to determine if the endpoint is alive.
This series removed the endpoint_state::is_alive state and moves all the logic to gossiper::is_alive
that bases its decision on the endpoint having an endpoint_state and being in the _live_endpoints set.
For that, the _live_endpoints is made sure to be replicated to all shards when changed
and the endpoint_state changes are serialized under lock_endpoint, and also making sure that the
endpoint_state in the _endpoint_states_map is never updated in place, but rather a temporary copy is changed
and then safely replicated using gossiper::replicate
Refs https://github.com/scylladb/scylladb/issues/14794Closes#14801
* github.com:scylladb/scylladb:
gossiper: mark_alive: remove local_state param
endpoint_state: get rid of _is_alive member and methods
gossiper: is_alive: use _live_endpoints
gossiper: evict_from_membership: erase endpoint from _live_endpoints
gossiper: replicate_live_endpoints_on_change: use _live_endpoints_version to detect change
gossiper: run: no need to replicate live_endpoints
gossiper: fold update_live_endpoints_version into replicate_live_endpoints_on_change
gossiper: add mutate_live_and_unreachable_endpoints
gossiper: reset_endpoint_state_map: clear also shadow endpoint sets
gossiper: reset_endpoint_state_map: clear live/unreachable endpoints on all shards
gossiper: functions that change _live_endpoints must be called on shard 0
gossiper: add lock_endpoint_update_semaphore
gossiper: make _live_endpoints an unordered_set
endpoint_state: use gossiper::is_alive externally