Alert-Plugin-Guide.md

Alert Plugin Guide

We can build our own alarm rules by handling alert scripting plugins which are able to compose various performance metrics.

How to

Alert script file can be edited from scouter client ui or directly in scouter server.

A. scripting in scouter client UI.

1. open the alert scripting view in the context menu of a server in the object view.

2. edit script & save it.

B. scripting in scouter server.

1. create 2 files in the server plugin directory ([server_running_dir]/plugin by default)

   • [PERFORMANCE_COUNTER_NAME].alert : script for alarm
   • [PERFORMANCE_COUNTER_NAME].conf : configuration for this alarm

2. [PERFORMANCE_COUNTER_NAME].conf

• history_size=150
  silent_time=300
  check_time=30

• history_size : data count that will be kept
  • if it is set as 150ea, the oldest data may be 300 seconds before data because Scouter counter data is sent every 2 seconds.
• silent_time : alarm sleep time - If the alarm is occurred in past [x] seconds, the same alarm is ignored.
• check_time : script([PERFORMANCE_COUNTER_NAME].alert) invoking interval.

3. [PERFORMANCE_COUNTER_NAME].alert

• script file for alert rule (java)

• sample1 (GcTime.alert)

  • alert when GcTime is over than 2 sec

  // void process(RealCounter $counter, PluginHelper $$)
  int gcTime = $counter.intValue();
  if(gcTime > 2000) {
     $counter.fatal("gc time fatal", "gc time:" + respTime + "ms");
  }

• sample2 (Elasped90%.alert)

  • alert when Elasped90% is over than 1.5 sec (ignore when TPS is lower than 3 sec.)

  // void process(RealCounter $counter, PluginHelper $$)
  int warn = 1500;
  int fatal = 2000;
  
  int tps = $counter.intValue("TPS");
  int respTime = $counter.intValue();
  
  String objType = $counter.objType();
  String objName = $counter.objName();
  
  if(tps < 3) return;
  if(respTime > fatal) {
          $counter.fatal("resp time fatal high", "90% resp time:" + $$.formatNumber(respTime) + "ms, tps:" + tps);
  } else if(respTime > warn) {
          $counter.warn("resp time warn high", "90% resp time:" + $$.formatNumber(respTime) + "ms, tps:" + tps);
  }

• sample3 (TPS.alert)

  • alert when TPS increase or decrease sharply.

  // void process(RealCounter $counter, PluginHelper $$)
  
  //increase
  float initTps = 20.0;
  float warnIncreaseRate = 1.2;
  float fatalIncreaseRate = 1.5;
  int compareBeforeSec = 180;
  
  //decrease
  float fatal1DecreaseRate = 0.7; //30%
  float fatal2DecreaseRate = 0.5; //50%
  int compareBeforeDecreaseSec = 120; //last 2 minute
  
  float tps = $counter.floatValue();
  String objType = $counter.objType();
  String objName = $counter.objName();
  float errorRate = $counter.floatValue();
  
  if(tps > initTps) {
      float preValue = $counter.getAvg(compareBeforeSec, 4);
      if(preValue > 0.0f) {
          if(tps > preValue * fatalIncreaseRate) {
              $counter.fatal("TPS increase fatal"
                  , "TPS is " + $$.formatNumber((double)tps/preValue*100) + "% higher than " + compareBeforeSec + "sec ago"
                      + ", TPS: " + tps);
  
          } else if(tps > preValue * warnIncreaseRate) {
              $counter.warn("TPS increase warning"
                  , "TPS is " + $$.formatNumber((double)tps/preValue*100) + "% higher than " + compareBeforeSec + "sec ago"
                      + ", TPS: " + tps);
          }
      }
  }
  
  float preValue = $counter.getAvg(compareBeforeDecreaseSec, 4);
  if(preValue > 5.0f) {
      if(tps < preValue * fatal2DecreaseRate) {
          $counter.fatal("TPS decrease fatal"
                  , "TPS is " + $$.formatNumber(((double)1-tps/preValue)*100) + "% lower than " + compareBeforeDecreaseSec + "sec ago"
                      + ", TPS: " + tps);
      } else if(tps < preValue * fatal1DecreaseRate) {
          $counter.error("TPS decrease warn"
                  , "TPS is " + $$.formatNumber((double)(1-tps/preValue)*100) + "% lower than " + compareBeforeDecreaseSec + "sec ago"
                      + ", TPS: " + tps);
      }
  }

RealCounter API

method	desc
objName()	get object's name that produced the counter value
objType()	get object's type that produced the counter value
intValue()	get counter value as integer
floatValue()	get counter value as float
historySize()	get history size set by the conf file
overCount(int value, int sec)	get how many times exceed the value in the seconds
overCount(float value, int sec)	get how many times exceed the value in the seconds
getAvg(int fromAgoSec, int durationSec)	calculate average of the counter values in fromAgoSec for durationSec
getLatestAvg(int durationSec)	calculate average of the counter values from durationSec ago to now
info(String title, String message)	invoke alarm as info level
warn(String title, String message)	invoke alarm as warn level
error(String title, String message)	invoke alarm as error level
fatal(String title, String message)	invoke alarm as fatal level
floatValue(String anotherCounterName)	get another counter's current value by the name
intValue(String anotherCounterName)	get another counter's current value by the name

Counter names

• counters.xml

$$ (PluginHelper) API

• Refer to PluginHelper API