Module lb_active

Active load balancing core module.

Copyright © 2014-2015 Zuse Institute Berlin 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.

Version: $Id$

Behaviours: gen_component.

Authors: Maximilian Michels (michels@zib.de).

Description

Active load balancing core module

Data Types

dht_message()

dht_message() = {lb_active, reset_db_monitors}
              | {lb_active,
                 balance,
                 HeavyNode :: lb_info:lb_info(),
                 LightNode :: lb_info:lb_info(),
                 LightNodeSucc :: lb_info:lb_info(),
                 Options :: options()}

erlang_timestamp()

erlang_timestamp() = 
    {MegaSecs :: non_neg_integer(),
     Secs :: 0..999999,
     MicroSecs :: 0..999999}

lb_op()

lb_op() = 
    #lb_op{id = uid:global_uid(),
           type = slide_pred | slide_succ | jump,
           heavy_node = node:node_type(),
           light_node = node:node_type(),
           light_node_succ = node:node_type(),
           target = rt_chord:key(),
           data_time = erlang_timestamp(),
           time = erlang_timestamp()}

message()

message() = {lb_stats_trigger}
          | {reset_monitors}
          | {gossip_reply,
             LightNode :: lb_info:lb_info(),
             HeavyNode :: lb_info:lb_info(),
             LightNodeSucc :: lb_info:lb_info(),
             Options :: options(),
             {gossip_get_values_best_response,
              LoadInfo :: gossip_load:load_info()}}
          | {balance_phase1, Op :: lb_op()}
          | {balance_phase2a, Op :: lb_op()}
          | {balance_phase2b, Op :: lb_op()}
          | {balance_failed, OpId :: uid:global_uid()}
          | {balance_success, OpId :: uid:global_uid()}
          | {move,
             result,
             Tag ::
                 {jump | slide_pred | slide_succ,
                  OpId :: uid:global_uid()},
             Result :: ok | dht_node_move:abort_reason()}
          | {web_debug_info, Requestor :: pid()}

my_state()

my_state() = 
    #my_state{last_balance = erlang_timestamp(),
              last_db_monitor_reset = erlang_timestamp(),
              pending_op = lb_op() | nil}

options()

options() = [tuple()]

state()

abstract datatype: state()

Function Index

balance_nodes/3
balance_nodes/4
balance_noop/1
check_config/0config check registered in config.erl.
check_gossip_modules/2
get_last_db_monitor_init/1
handle_dht_msg/2Process load balancing messages sent to the dht node.
init/1Initialization of core module and lb_stats.
is_enabled/0
on/2On handler after initialization.
requests_balance/0
start_gen_component/5
start_link/1Start this process as a gen component and register it in the dht node group.

Function Details

start_gen_component/5

start_gen_component(Module :: module(),
                    Handler :: gen_component:handler(),
                    Args :: term(),
                    Options :: [gen_component:option()],
                    Self :: pid()) ->
                       no_return() | ok

start_link/1

start_link(DHTNodeGroup :: pid_groups:groupname()) -> {ok, pid()}

Start this process as a gen component and register it in the dht node group

init/1

init(X1 :: []) -> state()

Initialization of core module and lb_stats

on/2

on(Msg :: message(), State :: state()) -> state()

On handler after initialization

balance_nodes/3

balance_nodes(HeavyNode :: lb_info:lb_info(),
              LightNode :: lb_info:lb_info(),
              Options :: options()) ->
                 ok

balance_nodes/4

balance_nodes(HeavyNode :: lb_info:lb_info(),
              LightNode :: lb_info:lb_info(),
              LightNodeSucc :: lb_info:lb_info() | nil,
              Options :: options()) ->
                 ok

balance_noop/1

balance_noop(Options :: options()) -> ok

handle_dht_msg/2

handle_dht_msg(Msg :: dht_message(),
               DhtState :: dht_node_state:state()) ->
                  dht_node_state:state()

Process load balancing messages sent to the dht node

is_enabled/0

is_enabled() -> boolean()

requests_balance/0

requests_balance() -> boolean()

get_last_db_monitor_init/1

get_last_db_monitor_init(MyState :: my_state()) ->
                            erlang_timestamp()

check_gossip_modules/2

check_gossip_modules(RequiredModule :: atom(),
                     DependencyKey :: atom()) ->
                        boolean()

check_config/0

check_config() -> boolean()

config check registered in config.erl


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