title: Cloudera Manager add services failed with ArithmeticException
body: <p>I've installed Cloudera Manager in a three-machine cluster. While I added CDH5 services (including Hive,Spark,Yarn...) to cluster, it then failed with "ArithmeticException: / by zero". </p>
  
  <pre><code>
  version: Cloudera Enterprise Data Hub Edition trail 5.4.5 (#5 built by jenkins on 20150728-0320 git: ...)
  org.drools.runtime.rule.ConsequenceException:Exception executing consequence for rule "Compute hiveserver2_spark_executor_cores" in com.cloudera.cmf.rules: org.drools.RuntimeDroolsException: java.lang.ArithmeticException: / by zero
  at DefaultConsequenceExceptionHandler.java line 39
  in org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler handleException()
  </code></pre>
  
  <p>Last caused-by is:</p>
  
  <pre><code>Caused by: java.lang.ArithmeticException:/ by zero
  at ComputationFunctions.java line 278
  in com.cloudera.cmf.rules.ComputationFunctions calculateHiveSparkExecutorMemoryTotal()
  
  1. ComputationFunctions.java line 278
  in com.cloudera.cmf.rules.ComputationFunctions calculateHiveSparkExecutorMemoryTotal()
  2. Rule_Compute_HiveServer2_executor_and_driver_memory_and_overehead_25364fb53f7d4bf08ec8a11bca01bcf8.java line 16
  in com.cloudera.cmf.rules.Rule_Compute_HiveServer2_executor_and_driver_memory_and_overehead_25364fb53f7d4bf08ec8a11bca01bcf8 accumulateExpression1()
  3. Rule_Compute_HiveServer2_executor_and_driver_memory_and_overehead_25364fb53f7d4bf08ec8a11bca01bcf8AccumulateExpression1Invoker.java line 31
  in com.cloudera.cmf.rules.Rule_Compute_HiveServer2_executor_and_driver_memory_and_overehead_25364fb53f7d4bf08ec8a11bca01bcf8AccumulateExpression1Invoker evaluate()
  4. JavaAccumulatorFunctionExecutor.java line 107
  in org.drools.base.accumulators.JavaAccumulatorFunctionExecutor accumulate()
  5. Accumulate.java line 173
  in org.drools.rule.Accumulate accumulate()
  ......
  </code></pre>
  
  <p>Anybody help? Or tells me where these compiled class such as "Rule_Compute_HiveServer2_executor_and_driver_memory_and_overehead_25364fb53f7d4bf08ec8a11bca01bcf8.java" is placed. I attempt to replace this class with more debug message.</p>
  
  <p>Many thanks,</p>