Skip to content

Don't allow a non-voter to start elections #525

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
kjnilsson merged 4 commits into from
Mar 17, 2025
Merged

Don't allow a non-voter to start elections #525

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
114d1d3
Don't allow a non-voter to start elections
mkuratczyk Mar 14, 2025
e6b0757
Add a test for pre-vote reply from non-voter
mkuratczyk Mar 14, 2025
207e812
Refactor try_become_leader
mkuratczyk Mar 17, 2025
215611c
Emit election_timeout as an effect
mkuratczyk Mar 17, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 10 additions & 12 deletions src/ra_server.erl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -920,12 +920,12 @@ handle_leader({transfer_leadership, ServerId},
?DEBUG("~ts: transfer leadership to ~w requested",
[LogId, ServerId]),
%% TODO find a timeout
gen_statem:cast(ServerId, try_become_leader),
{await_condition,
State#{condition =>
#{predicate_fun => fun transfer_leadership_condition/2,
timeout => #{effects => [], transition_to => leader}}},
[{reply, ok}]}
timeout => #{effects => [],
transition_to => leader}}},
[{reply, ok}, {send_msg, ServerId, election_timeout, cast}]}
end;
handle_leader({register_external_log_reader, Pid}, #{log := Log0} = State) ->
{Log, Effs} = ra_log:register_reader(Pid, Log0),
Expand Down Expand Up @@ -1113,7 +1113,8 @@ handle_pre_vote(#pre_vote_result{term = Term, vote_granted = true,
votes := Votes,
cfg := #cfg{log_id = LogId},
pre_vote_token := Token,
cluster := Nodes} = State0) ->
cluster := Nodes,
membership := voter} = State0) ->
?DEBUG("~ts: pre_vote granted ~w for term ~b votes ~b",
[LogId, Token, Term, Votes + 1]),
NewVotes = Votes + 1,
Expand All @@ -1124,17 +1125,14 @@ handle_pre_vote(#pre_vote_result{term = Term, vote_granted = true,
_ ->
{pre_vote, State#{votes => NewVotes}, []}
end;
handle_pre_vote(#pre_vote_result{vote_granted = false}, State) ->
handle_pre_vote(#pre_vote_result{}, State) ->
%% just handle negative results to avoid printing an unhandled message log
{pre_vote, State, []};
handle_pre_vote(#pre_vote_rpc{} = PreVote, State) ->
process_pre_vote(pre_vote, PreVote, State);
handle_pre_vote(#request_vote_result{}, State) ->
%% handle to avoid logging as unhandled
{pre_vote, State, []};
handle_pre_vote(#pre_vote_result{}, State) ->
%% handle to avoid logging as unhandled
{pre_vote, State, []};
handle_pre_vote(election_timeout, State) ->
call_for_election(pre_vote, State);
handle_pre_vote({ra_log_event, Evt}, State = #{log := Log0}) ->
Expand Down Expand Up @@ -1360,15 +1358,15 @@ handle_follower({ra_log_event, Evt}, #{log := Log0,
handle_follower(#pre_vote_rpc{},
#{cfg := #cfg{log_id = LogId},
membership := Membership} = State) when Membership =/= voter ->
?DEBUG("~ts: follower ignored pre_vote_rpc, non-voter: ~p0",
?DEBUG("~ts: follower ignored pre_vote_rpc, non-voter: ~0p",
[LogId, Membership]),
{follower, State, []};
handle_follower(#pre_vote_rpc{} = PreVote, State) ->
process_pre_vote(follower, PreVote, State);
handle_follower(#request_vote_rpc{},
#{cfg := #cfg{log_id = LogId},
membership := Membership} = State) when Membership =/= voter ->
?DEBUG("~ts: follower ignored request_vote_rpc, non-voter: ~p0",
?DEBUG("~ts: follower ignored request_vote_rpc, non-voter: ~0p",
[LogId, Membership]),
{follower, State, []};
handle_follower(#request_vote_rpc{candidate_id = Cand, term = Term},
Expand Down Expand Up @@ -1485,13 +1483,13 @@ handle_follower(#append_entries_reply{}, State) ->
handle_follower(election_timeout,
#{cfg := #cfg{log_id = LogId},
membership := Membership} = State) when Membership =/= voter ->
?DEBUG("~ts: follower ignored election_timeout, non-voter: ~p0",
?INFO("~ts: follower ignored election_timeout, non-voter: ~0p",
[LogId, Membership]),
{follower, State, []};
handle_follower(election_timeout, State) ->
call_for_election(pre_vote, State);
handle_follower(try_become_leader, State) ->
call_for_election(pre_vote, State);
handle_follower(election_timeout, State);
handle_follower({register_external_log_reader, Pid}, #{log := Log0} = State) ->
{Log, Effs} = ra_log:register_reader(Pid, Log0),
{follower, State#{log => Log}, Effs};
Expand Down
11 changes: 11 additions & 0 deletions test/ra_server_SUITE.erl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@ all() ->
leader_does_not_abdicate_to_unknown_peer,
higher_term_detected,
pre_vote_election,
pre_vote_election_non_voter,
pre_vote_election_reverts,
candidate_receives_pre_vote,
leader_receives_pre_vote,
Expand Down Expand Up @@ -2104,6 +2105,7 @@ candidate_election(_Config) ->
pre_vote_election(_Config) ->
Token = make_ref(),
State = (base_state(5, ?FUNCTION_NAME))#{votes => 1,
membership => voter,
pre_vote_token => Token},
Reply = #pre_vote_result{term = 5, token = Token, vote_granted = true},
{pre_vote, #{votes := 2} = State1, []}
Expand All @@ -2129,6 +2131,15 @@ pre_vote_election(_Config) ->
{candidate,
#{current_term := 6}, _} = ra_server:handle_pre_vote(Reply, State1).

pre_vote_election_non_voter(_Config) ->
Token = make_ref(),
State = (base_state(5, ?FUNCTION_NAME))#{votes => 1,
membership => promotable,
pre_vote_token => Token},
Reply = #pre_vote_result{term = 5, token = Token, vote_granted = true},
% non-voter should ignore pre-vote
{pre_vote, #{votes := 1}, []} = ra_server:handle_pre_vote(Reply, State).

pre_vote_election_reverts(_Config) ->
N2 = ?N2,
Token = make_ref(),
Expand Down