Hi everyone,
We are a group of researchers at DePaul University investigating the use of tactics in open-source, high-performance, fault-tolerant software systems. Obviously we are not nearly as familiar with Hadoop as all of the developers are, so we hoped you could help us. We have focused particularly on 5 arcjitectural tactics and have listed the tactics we found in the attached table. Do you think we found all the major occurrences of these tactics in Hadoop? Any help or insights you could provide us would be very helpful. Many thanks, MM, JCH, YS, MC. *Tactic* *Number of tactic-related classes identified* *Explanation* *Packages / Location* Heartbeat 10 The heartbeat with piggybacking is used in Hadoop to check the health status of each task. mapreduce\src\java\org\apache\hadoop\mapred\TaskTracker.java mapreduce\src\java\org\apache\hadoop\mapreduce\server\tasktracker\TTConfig.java mapreduce\src\contrib\mumak\src\java\org\apache\hadoop\mapred\SimulatorTaskTracker.java mapreduce\src\contrib\mumak\src\java\org\apache\hadoop\mapred\SimulatorEngine.java mapreduce\src\java\org\apache\hadoop\mapred\JobTracker.java mapreduce\src\java\org\apache\hadoop\mapred\TaskTrackerManager.java mapreduce\src\java\org\apache\hadoop\mapreduce\server\jobtracker\JTConfig.java mapreduce\src\contrib\mumak\src\java\org\apache\hadoop\mapred\SimulatorJobTracker.java mapreduce\src\java\org\apache\hadoop\mapred\InterTrackerProtocol.java mapreduce\src\java\org\apache\hadoop\mapreduce\util\ConfigUtil.java Resource Pooling 70 Thread pooling is used to increase the performance mapred package 47 Block pooling is used to save and reuse data blocks hdfs subsystem 3 Job pooling: For increasing the performace the scheduler actually organizes jobs further into "pools", and shares resources fairly between these pools. mapreduce\src\contrib\fairscheduler\src\java\org\apache\hadoop\mapred\Pool.java mapreduce\src\contrib\fairscheduler\src\java\org\apache\hadoop\mapred\PoolManager.java mapreduce\src\contrib\fairscheduler\src\java\org\apache\hadoop\mapred\PoolSchedulable.java Scheduling 96 Three different scheduling service have been implemented to executes task and jobs. The scheduling strategies are fairScheduler, Dynamic Scheduling and Capacity Scheduling mapreduce\src\contrib\dynamic-scheduler\ src\java\org\apache\hadoop\mapred\DynamicPriorityScheduler.java mapreduce\src\contrib\dynamic-scheduler\ mapreduce\src\contrib\fairscheduler\ mapreduce\src\contrib\capacity-scheduler\ Audit Trail 7 Audit log is used to capture information about authorization/authentication events (success/failure) mapreduce\src\java\org\apache\hadoop\mapred\AuditLogger.java mapreduce\src\java\org\apache\hadoop\mapred\JobTracker.java mapreduce\src\java\org\apache\hadoop\mapred\JobInProgress.java mapreduce\src\java\org\apache\hadoop\mapred\ACLsManager.java common\src\test\core\org\apache\hadoop\ipc\MiniRPCBenchmark.java common\src\java\org\apache\hadoop\ipc\Server.java common\src\java\org\apache\hadoop\security\authorize\ServiceAuthorizationManager.java Authenticate 36 Authentication is used for controling users access *common\src\java\org\apache\hadoop\security * mapreduce\src\java\org\apache\hadoop\mapred\pipes\OutputHandler.java mapreduce\src\java\org\apache\hadoop\mapred\pipes\UpwardProtocol.java common\src\java\org\apache\hadoop\ipc\Client.java common\src\test\core\org\apache\hadoop\ipc\MiniRPCBenchmark.java hdfs\src\java\org\apache\hadoop\hdfs\server\common\JspHelper.java hdfs\src\java\org\apache\hadoop\hdfs\server\datanode\SecureDataNodeStarter.java hdfs\src\java\org\apache\hadoop\hdfs\server\namenode\CancelDelegationTokenServlet.java hdfs\src\java\org\apache\hadoop\hdfs\server\namenode\FSNamesystem.java common\src\java\org\apache\hadoop\http\lib\StaticUserWebFilter.java common\src\java\org\apache\hadoop\ipc\ConnectionHeader.java mapreduce\src\java\org\apache\hadoop\mapred\pipes\Application.java mapreduce\src\java\org\apache\hadoop\mapred\JobInProgress.java mapreduce\src\java\org\apache\hadoop\mapred\JobTracker.java mapreduce\src\java\org\apache\hadoop\mapred\TaskTracker.java common\src\java\org\apache\hadoop\ipc\Server.java common\src\java\org\apache\hadoop\ipc\metrics\RpcMetrics.java
