Package org.apache.accumulo.core.client.admin

Interface ResourceGroupOperations

public interface ResourceGroupOperations
A ResourceGroup is a grouping of Accumulo server processes that have some shared characteristic that is different than server processes in other resource groups. Examples could be homogeneous hardware configurations for the server processes in one resource group but different than other resource groups, or a resource group could be created for physical separation of processing for table(s), or to dedicate compute resources for scans, compactions, and ingest for specific tables. A default resource group exists in which all server processes are assigned. The Manager, Monitor, and GarbageCollector are assigned to the default resource group. Compactor, ScanServer and TabletServer processes are also assigned to the default resource group, unless their respective properties are set. This object is for defining, interacting, and removing resource group configurations. When the Accumulo server processes get the system configuration, they will receive a merged view of the system configuration and applicable resource group configuration, with any property defined in the resource group configuration given higher priority.
Since:
4.0.0

  • Method Details

    • exists

      boolean exists(String group)
      A method to check if a resource group configuration exists in Accumulo.
      Parameters:
      group - the name of the resource group
      Returns:
      true if the group exists

    • list

      Set<ResourceGroupId> list()
      Retrieve a list of resource groups in Accumulo.
      Returns:
      Set of resource groups in accumulo
      Throws:
      IllegalStateException - if default resource group does not exist

    • create

      void create(ResourceGroupId group) throws AccumuloException, AccumuloSecurityException
      Create a configuration node in zookeeper for a resource group. If not defined, then processes running in the resource group will use the values of the properties defined in the system configuration.
      Parameters:
      group - resource group
      Throws:
      AccumuloException - if a general error occurs
      AccumuloSecurityException - if the user does not have permission

    • getProperties

      Map<String,String> getProperties(ResourceGroupId group) throws AccumuloException, AccumuloSecurityException, ResourceGroupNotFoundException
      Returns the un-merged properties set for this resource group in zookeeper.
      Parameters:
      group - resource group
      Returns:
      Map of property keys/values
      Throws:
      AccumuloException - if a general error occurs
      AccumuloSecurityException - if the user does not have permission
      ResourceGroupNotFoundException - if the specified resource group doesn't exist

    • setProperty

      void setProperty(ResourceGroupId group, String property, String value) throws AccumuloException, AccumuloSecurityException, ResourceGroupNotFoundException
      Sets a resource group property in zookeeper. Servers will pull this setting and override the equivalent setting in accumulo.properties. Changes can be seen using #getProperties(ResourceGroupId) or InstanceOperations.getSystemConfiguration() can be used to return a system-level merged view.

      Only some properties can be changed by this method, an IllegalArgumentException will be thrown if there is an attempt to set a read-only property.

      Parameters:
      group - resource group
      property - the name of a system property
      value - the value to set a system property to
      Throws:
      AccumuloException - if a general error occurs
      AccumuloSecurityException - if the user does not have permission
      ResourceGroupNotFoundException - if the specified resource group doesn't exist

    • modifyProperties

      Map<String,String> modifyProperties(ResourceGroupId group, Consumer<Map<String,String>> mapMutator) throws AccumuloException, AccumuloSecurityException, IllegalArgumentException, ResourceGroupNotFoundException
      Modify resource group properties using a Consumer that accepts a mutable map containing the current system property overrides stored in ZooKeeper. If the supplied Consumer alters the map without throwing an Exception, then the resulting map will atomically replace the current system property overrides in ZooKeeper. Only properties which can be stored in ZooKeeper will be accepted.

      Accumulo has multiple layers of properties that for many APIs and SPIs are presented as a single merged view. This API does not offer that merged view, it only offers the properties set at the resource group layer to the mapMutator.

      Below is an example of using this API to conditionally set some instance properties. If while trying to set the compaction planner properties another process modifies the manager balancer properties, then it would automatically retry and call the lambda again with the latest snapshot of instance properties. 

               
             AccumuloClient client = getClient();
             Map<String,String> acceptedProps = client.resourceGroupOperations().modifyProperties(groupId, currProps -> {
               var planner = currProps.get("compaction.service.default.planner");
               //This code will only change the compaction planner if its currently set to default settings.
               //The endsWith() function was used to make the example short, would be better to use equals().
               if(planner != null && planner.endsWith("RatioBasedCompactionPlanner") {
                 // tservers will eventually see these compaction planner changes and when they do they will see all of the changes at once
                 currProps.keySet().removeIf(
                    prop -> prop.startsWith("compaction.service.default.planner.opts."));
                 currProps.put("compaction.service.default.planner","MyPlannerClassName");
                 currProps.put("compaction.service.default.planner.opts.myOpt1","val1");
                 currProps.put("compaction.service.default.planner.opts.myOpt2","val2");
                }
             });

             // Since three properties were set may want to check for the values of all
             // three, just checking one in this example to keep it short.
             if("MyPlannerClassName".equals(acceptedProps.get("compaction.service.default.planner"))){
                // the compaction planner change was accepted or already existed, so take action for that outcome
             } else {
                // the compaction planner change was not done, so take action for that outcome
             }
           
         }
      Parameters:
      group - resource group
      mapMutator - This consumer should modify the passed snapshot of resource group properties to contain the desired keys and values. It should be safe for Accumulo to call this consumer multiple times, this may be done automatically when certain retryable errors happen. The consumer should probably avoid accessing the Accumulo client as that could lead to undefined behavior.
      Returns:
      The map that became Accumulo's new properties for this resource group. This map is immutable and contains the snapshot passed to mapMutator and the changes made by mapMutator.
      Throws:
      AccumuloException - if a general error occurs
      AccumuloSecurityException - if the user does not have permission
      IllegalArgumentException - if the Consumer alters the map by adding properties that cannot be stored in ZooKeeper
      ResourceGroupNotFoundException - if the specified resource group doesn't exist

    • removeProperty

      void removeProperty(ResourceGroupId group, String property) throws AccumuloException, AccumuloSecurityException, ResourceGroupNotFoundException
      Removes a resource group property from zookeeper. Changes can be seen using #getProperties(ResourceGroupId) or InstanceOperations.getSystemConfiguration() can be used to return a system-level merged view.
      Parameters:
      group - resource group
      property - the name of a system property
      Throws:
      AccumuloException - if a general error occurs
      AccumuloSecurityException - if the user does not have permission
      ResourceGroupNotFoundException - if the specified resource group doesn't exist

    • remove

      void remove(ResourceGroupId group) throws AccumuloException, AccumuloSecurityException, ResourceGroupNotFoundException
      Removes a configuration node in zookeeper for a resource group. If not defined, then processes running in the resource group will use the values of the properties defined in the system configuration.
      Parameters:
      group - resource group
      Throws:
      AccumuloException - if a general error occurs
      AccumuloSecurityException - if the user does not have permission
      ResourceGroupNotFoundException - if the specified resource group doesn't exist
      IllegalArgumentException - if user tries to remove the default resource group