Package org.apache.hadoop.yarn.server.resourcemanager.placement.csmappingrule

Class MappingRuleActions.VariableUpdateAction

java.lang.Object
org.apache.hadoop.yarn.server.resourcemanager.placement.csmappingrule.MappingRuleActionBase
org.apache.hadoop.yarn.server.resourcemanager.placement.csmappingrule.MappingRuleActions.VariableUpdateAction
All Implemented Interfaces:
MappingRuleAction
Enclosing class:
MappingRuleActions
public static class MappingRuleActions.VariableUpdateAction extends MappingRuleActionBase
VariableUpdateAction represents the action which alters one of the mutable variables in the variable context, but doesn't do anything with the application. This can be used to change the default queue or define custom variables to be used later.

  • Method Details

    • execute

      public MappingRuleResult execute(VariableContext variables)
      This execute is a bit special, compared to other actions, since it does not affect the placement of the application, but changes the variable context. So it always returns a skip result in order to ensure the rule evalutaion continues after the variable update. The exectute method will do the update to the variable context the variable name stored in variableName will be updated with the value stored in variableValue, but all variables in the variableValue will gets resolved first, so this way dynamic updates are possible.
      Specified by:
      execute in interface MappingRuleAction
      Specified by:
      execute in class MappingRuleActionBase
      Parameters:
      variables - The variable context, which contains all the variables
      Returns:
      Always a skip result.

    • validate

      public void validate(MappingRuleValidationContext ctx) throws org.apache.hadoop.yarn.exceptions.YarnException
      During the validation process we add the variable set by this action to the known variables, to make sure the context is aware that we might introduce a new custom variable. All rules after this may use this variable. If the variable cannot be added (eg. it is already added as immutable), an exception will be thrown, and the validation will fail.
      Parameters:
      ctx - Validation context with all the necessary objects and helper methods required during validation
      Throws:
      org.apache.hadoop.yarn.exceptions.YarnException - If the variable cannot be added to the context

    • toString

      public String toString()
      Overrides:
      toString in class Object