Before the patch we called `gossiper.remove_endpoint` for IP-s of the
left nodes. The problem is that in replace-with-same-ip scenario we
called `gossiper.remove_endpoint` for IP which is used by the new,
replacing node. The `gossiper.remove_endpoint` method puts the IP into
quarantine, which means gossiper will ignore all events about this IP
for `quarantine_delay` (one minute by default). If we immediately
replace just replaced node with the same IP again, the bootstrap will
fail since the gossiper events are blocked for this IP, and we won't be
able to resolve an IP for the new host_id.
Another problem was that we called gossiper.remove_endpoint method,
which doesn't remove an endpoint from `_endpoint_state_map`, only from
live and unreachable lists. This means the IP will keep circulating in
the gossiper message exchange between cluster nodes until full cluster
restart.
This patch fixes both of these problems. First, we rely on the fact that
when topology coordinator moves the `being_replaced` node to the left
state, the IP of the `replacing` node is known to all nodes. This means
before removing an IP from the gossiper we can check if this IP is
currently used by another node in the current raft topology. This is
done by constructing the `used_ips` map based on normal and transition
nodes. This map is cached to avoid quadratic behaviour.
Second, we call `gossiper.force_remove_endpoint`, not
`gossiper.remove_endpoint`. This function removes and IP from
`_endpoint_state_map`, as well as from live and unreachable lists.
Closesscylladb/scylladb#16820
* github.com:scylladb/scylladb:
get_peer_info_for_update: update only required fields in raft topology mode
get_peer_info_for_update: introduce set_field lambda
storage_service::on_change: fix indent
storage_service::on_change: skip handle_state functions in raft topology mode
test_replace_different_ip: check old IP is removed from gossiper
test_replace: check two replace with same IP one after another
storage_service: sync_raft_topology_nodes: force_remove_endpoint for left nodes only if an IP is not used by other nodes
1007ac4956