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ns_orchestrator.erl
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ns_orchestrator.erl
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%% @author Northscale <info@northscale.com>
%% @copyright 2010 NorthScale, Inc.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% Monitor and maintain the vbucket layout of each bucket.
%% There is one of these per bucket.
%%
-module(ns_orchestrator).
-behaviour(gen_fsm).
-include("ns_common.hrl").
%% Constants and definitions
-record(idle_state, {remaining_buckets=[]}).
-record(janitor_state, {remaining_buckets, pid}).
-record(rebalancing_state, {rebalancer, progress}).
%% API
-export([create_bucket/3,
delete_bucket/1,
failover/1,
needs_rebalance/0,
rebalance_progress/0,
start_link/0,
start_rebalance/3,
stop_rebalance/0,
update_progress/1
]).
-define(SERVER, {global, ?MODULE}).
-define(REBALANCE_SUCCESSFUL, 1).
-define(REBALANCE_FAILED, 2).
-define(REBALANCE_NOT_STARTED, 3).
-define(REBALANCE_STARTED, 4).
-define(REBALANCE_PROGRESS, 5).
%% gen_fsm callbacks
-export([code_change/4,
init/1,
handle_event/3,
handle_info/3,
handle_sync_event/4,
terminate/3]).
%% States
-export([idle/2, idle/3,
janitor_running/2, janitor_running/3,
rebalancing/2, rebalancing/3]).
%%
%% API
%%
start_link() ->
misc:start_singleton(gen_fsm, ?MODULE, [], []).
-spec create_bucket(memcached|membase, nonempty_string(), list()) ->
ok | {exit, {already_exists, nonempty_string()}, any()} |
{error, {port_conflict, integer()}} |
{error, {invalid_name, nonempty_string()}} |
rebalance_running.
create_bucket(BucketType, BucketName, NewConfig) ->
gen_fsm:sync_send_event(?SERVER, {create_bucket, BucketType, BucketName,
NewConfig}, 20000).
%% deletes bucket. Makes sure that once it returns it's already dead.
delete_bucket(BucketName) ->
gen_fsm:sync_send_event(?SERVER, {delete_bucket, BucketName}, 20000).
-spec failover(atom()) -> ok.
failover(Node) ->
gen_fsm:sync_send_event(?SERVER, {failover, Node}, 20000).
-spec needs_rebalance() -> boolean().
needs_rebalance() ->
needs_rebalance(ns_node_disco:nodes_wanted()).
-spec needs_rebalance([atom(), ...]) -> boolean().
needs_rebalance(Nodes) ->
lists:any(fun ({_, BucketConfig}) -> needs_rebalance(Nodes, BucketConfig) end,
ns_bucket:get_buckets()).
-spec rebalance_progress() -> {running, [{atom(), float()}]} | not_running.
rebalance_progress() ->
try gen_fsm:sync_send_event(?SERVER, rebalance_progress, 2000) of
Result -> Result
catch
Type:Err ->
?log_error("Couldn't talk to orchestrator: ~p", [{Type, Err}]),
not_running
end.
-spec start_rebalance([node()], [node()], [node()]) ->
ok | in_progress | already_balanced.
start_rebalance(KeepNodes, EjectNodes, FailedNodes) ->
gen_fsm:sync_send_event(?SERVER, {start_rebalance, KeepNodes,
EjectNodes, FailedNodes}).
-spec stop_rebalance() -> ok | not_rebalancing.
stop_rebalance() ->
gen_fsm:sync_send_event(?SERVER, stop_rebalance).
%%
%% gen_fsm callbacks
%%
code_change(_OldVsn, StateName, StateData, _Extra) ->
{ok, StateName, StateData}.
init([]) ->
process_flag(trap_exit, true),
timer:send_interval(10000, janitor),
{ok, idle, #idle_state{}}.
handle_event(unhandled, unhandled, unhandled) ->
unhandled.
handle_sync_event(unhandled, unhandled, unhandled, unhandled) ->
unhandled.
handle_info(janitor, idle, #idle_state{remaining_buckets=[]} = State) ->
case ns_bucket:get_bucket_names(membase) of
[] -> {next_state, idle, State#idle_state{remaining_buckets=[]}};
Buckets ->
handle_info(janitor, idle,
State#idle_state{remaining_buckets=Buckets})
end;
handle_info(janitor, idle, #idle_state{remaining_buckets=Buckets}) ->
Bucket = hd(Buckets),
Pid = proc_lib:spawn_link(ns_janitor, cleanup, [Bucket]),
%% NOTE: Bucket will be popped from Buckets when janitor run will
%% complete successfully
{next_state, janitor_running, #janitor_state{remaining_buckets=Buckets,
pid = Pid}};
handle_info(janitor, StateName, StateData) ->
?log_info("Skipping janitor in state ~p: ~p", [StateName, StateData]),
{next_state, StateName, StateData};
handle_info({'EXIT', Pid, Reason}, janitor_running,
#janitor_state{pid = Pid,
remaining_buckets = Buckets}) ->
NextBuckets =
case Reason of
normal ->
tl(Buckets);
_ ->
?log_info("Janitor run completed for bucket ~p with reason ~p~n",
[hd(Buckets), Reason]),
Buckets
end,
case NextBuckets of
[] ->
ok;
_ ->
self() ! janitor
end,
{next_state, idle, #idle_state{remaining_buckets = NextBuckets}};
handle_info({'EXIT', Pid, Reason}, rebalancing,
#rebalancing_state{rebalancer=Pid}) ->
Status = case Reason of
normal ->
ns_log:log(?MODULE, ?REBALANCE_SUCCESSFUL,
"Rebalance completed successfully.~n"),
none;
_ ->
ns_log:log(?MODULE, ?REBALANCE_FAILED,
"Rebalance exited with reason ~p~n", [Reason]),
{none, <<"Rebalance failed. See logs for detailed reason. "
"You can try rebalance again.">>}
end,
ns_config:set(rebalance_status, Status),
{next_state, idle, #idle_state{}};
handle_info(Msg, StateName, StateData) ->
?log_warning("Got unexpected message ~p in state ~p with data ~p",
[Msg, StateName, StateData]),
{next_state, StateName, StateData}.
terminate(_Reason, _StateName, _StateData) ->
ok.
%%
%% States
%%
%% Asynchronous idle events
idle(_Event, State) ->
%% This will catch stray progress messages
{next_state, idle, State}.
janitor_running(_Event, State) ->
{next_state, janitor_running, State}.
%% Synchronous idle events
idle({create_bucket, BucketType, BucketName, NewConfig}, _From, State) ->
Reply = case ns_bucket:get_bucket(BucketName) of
not_present ->
%% Delete any leftover files.
rpc:multicall(ns_node_disco:nodes_actual_proper(),
ns_storage_conf,
delete_db_files,
[BucketName]),
ns_bucket:create_bucket(BucketType, BucketName, NewConfig);
_ ->
{already_exists, BucketName}
end,
{reply, Reply, idle, State};
idle({delete_bucket, BucketName}, _From, State) ->
RV = ns_bucket:delete_bucket(BucketName),
ns_config:sync_announcements(),
{reply, RV, idle, State};
idle({failover, Node}, _From, State) ->
?log_info("Failing over ~p", [Node]),
Result = ns_rebalancer:failover(Node),
{reply, Result, idle, State};
idle(rebalance_progress, _From, State) ->
{reply, not_running, idle, State};
idle({start_rebalance, KeepNodes, EjectNodes, FailedNodes}, _From,
_State) ->
ns_log:log(?MODULE, ?REBALANCE_STARTED,
"Starting rebalance, KeepNodes = ~p, EjectNodes = ~p~n",
[KeepNodes, EjectNodes]),
ns_config:set(rebalance_status, running),
Pid = spawn_link(
fun () ->
ns_rebalancer:rebalance(KeepNodes, EjectNodes, FailedNodes)
end),
{reply, ok, rebalancing, #rebalancing_state{rebalancer=Pid,
progress=dict:new()}};
idle(stop_rebalance, _From, State) ->
{reply, not_rebalancing, idle, State}.
janitor_running(rebalance_progress, _From, State) ->
{reply, not_running, janitor_running, State};
janitor_running(Msg, From, #janitor_state{pid=Pid} = State) ->
%% when handling some call while janitor is running we kill janitor
exit(Pid, shutdown),
%% than await that it's dead and handle it's death message
{next_state, idle, NextState}
= receive
{'EXIT', Pid, _} = DeathMsg ->
handle_info(DeathMsg, janitor_running, State)
end,
%% and than handle original call in idle state
idle(Msg, From, NextState).
%% Asynchronous rebalancing events
rebalancing({update_progress, Progress},
#rebalancing_state{progress=Old} = State) ->
NewProgress = dict:merge(fun (_, _, New) -> New end, Old, Progress),
{next_state, rebalancing,
State#rebalancing_state{progress=NewProgress}}.
%% Synchronous rebalancing events
rebalancing({failover, _Node}, _From, State) ->
{reply, rebalancing, rebalancing, State};
rebalancing(start_rebalance, _From, State) ->
ns_log:log(?MODULE, ?REBALANCE_NOT_STARTED,
"Not rebalancing because rebalance is already in progress.~n"),
{reply, in_progress, rebalancing, State};
rebalancing(stop_rebalance, _From,
#rebalancing_state{rebalancer=Pid} = State) ->
Pid ! stop,
{reply, ok, rebalancing, State};
rebalancing(rebalance_progress, _From,
#rebalancing_state{progress = Progress} = State) ->
{reply, {running, dict:to_list(Progress)}, rebalancing, State};
rebalancing(Event, _From, State) ->
?log_warning("Got event ~p while rebalancing.", [Event]),
{reply, rebalance_running, rebalancing, State}.
%%
%% Internal functions
%%
needs_rebalance(Nodes, BucketConfig) ->
Servers = proplists:get_value(servers, BucketConfig, []),
case proplists:get_value(type, BucketConfig) of
membase ->
case Servers of
[] -> false;
_ ->
Map = proplists:get_value(map, BucketConfig),
NumServers = length(Servers),
lists:sort(Nodes) /= lists:sort(Servers) orelse
lists:any(
fun (Chain) ->
lists:member(
undefined,
%% Don't warn about missing replicas when you have
%% fewer servers than your copy count!
lists:sublist(Chain, NumServers))
end, Map) orelse
ns_rebalancer:unbalanced(Map, Servers)
end;
memcached ->
lists:sort(Nodes) /= lists:sort(Servers)
end.
-spec update_progress(dict()) -> ok.
update_progress(Progress) ->
gen_fsm:send_event(?SERVER, {update_progress, Progress}).