[HADOOP-11724] DistCp throws NPE when the target directory is root.

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Target Version/s: 2.7.0
• Hadoop Flags: Reviewed
• Assignee: Lei (Eddy) Xu
• Reporter: Lei (Eddy) Xu
• Created: 17/Mar/15 18:51
• Updated: 30/Aug/16 01:30
• Resolved: 25/Mar/15 22:58

Description

Distcp throws NPE when the target directory is root. It is due to CopyCommitter#cleanupTempFiles attempts to delete parent directory of root, which is null:

$ hadoop distcp pom.xml hdfs://localhost/
15/03/17 11:17:44 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
15/03/17 11:17:45 INFO tools.DistCp: Input Options: DistCpOptions{atomicCommit=false, syncFolder=false, deleteMissing=false, ignoreFailures=false, maxMaps=20, sslConfigurationFile='null', copyStrategy='uniformsize', sourceFileListing=null, sourcePaths=[pom.xml], targetPath=hdfs://localhost/, targetPathExists=true, preserveRawXattrs=false}
15/03/17 11:17:45 INFO Configuration.deprecation: session.id is deprecated. Instead, use dfs.metrics.session-id
15/03/17 11:17:45 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId=
15/03/17 11:17:45 INFO Configuration.deprecation: io.sort.mb is deprecated. Instead, use mapreduce.task.io.sort.mb
15/03/17 11:17:45 INFO Configuration.deprecation: io.sort.factor is deprecated. Instead, use mapreduce.task.io.sort.factor
15/03/17 11:17:45 INFO jvm.JvmMetrics: Cannot initialize JVM Metrics with processName=JobTracker, sessionId= - already initialized
15/03/17 11:17:45 INFO mapreduce.JobSubmitter: number of splits:1
15/03/17 11:17:45 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_local992233322_0001
15/03/17 11:17:46 INFO mapreduce.Job: The url to track the job: http://localhost:8080/
15/03/17 11:17:46 INFO tools.DistCp: DistCp job-id: job_local992233322_0001
15/03/17 11:17:46 INFO mapreduce.Job: Running job: job_local992233322_0001
15/03/17 11:17:46 INFO mapred.LocalJobRunner: OutputCommitter set in config null
15/03/17 11:17:46 INFO output.FileOutputCommitter: File Output Committer Algorithm version is 1
15/03/17 11:17:46 INFO mapred.LocalJobRunner: OutputCommitter is org.apache.hadoop.tools.mapred.CopyCommitter
15/03/17 11:17:46 INFO mapred.LocalJobRunner: Waiting for map tasks
15/03/17 11:17:46 INFO mapred.LocalJobRunner: Starting task: attempt_local992233322_0001_m_000000_0
15/03/17 11:17:46 INFO output.FileOutputCommitter: File Output Committer Algorithm version is 1
15/03/17 11:17:46 INFO util.ProcfsBasedProcessTree: ProcfsBasedProcessTree currently is supported only on Linux.
15/03/17 11:17:46 INFO mapred.Task:  Using ResourceCalculatorProcessTree : null
15/03/17 11:17:46 INFO mapred.MapTask: Processing split: file:/tmp/hadoop/mapred/staging/lei2046334351/.staging/_distcp-1889397390/fileList.seq:0+220
15/03/17 11:17:46 INFO output.FileOutputCommitter: File Output Committer Algorithm version is 1
15/03/17 11:17:46 INFO mapred.CopyMapper: Copying file:/Users/lei/work/cloudera/s3a_cp_target/pom.xml to hdfs://localhost/pom.xml
15/03/17 11:17:46 INFO mapred.CopyMapper: Skipping copy of file:/Users/lei/work/cloudera/s3a_cp_target/pom.xml to hdfs://localhost/pom.xml
15/03/17 11:17:46 INFO mapred.LocalJobRunner:
15/03/17 11:17:46 INFO mapred.Task: Task:attempt_local992233322_0001_m_000000_0 is done. And is in the process of committing
15/03/17 11:17:46 INFO mapred.LocalJobRunner:
15/03/17 11:17:46 INFO mapred.Task: Task attempt_local992233322_0001_m_000000_0 is allowed to commit now
15/03/17 11:17:46 INFO output.FileOutputCommitter: Saved output of task 'attempt_local992233322_0001_m_000000_0' to file:/tmp/hadoop/mapred/staging/lei2046334351/.staging/_distcp-1889397390/_logs/_temporary/0/task_local992233322_0001_m_000000
15/03/17 11:17:46 INFO mapred.LocalJobRunner: Copying file:/Users/lei/work/cloudera/s3a_cp_target/pom.xml to hdfs://localhost/pom.xml
15/03/17 11:17:46 INFO mapred.Task: Task 'attempt_local992233322_0001_m_000000_0' done.
15/03/17 11:17:46 INFO mapred.LocalJobRunner: Finishing task: attempt_local992233322_0001_m_000000_0
15/03/17 11:17:46 INFO mapred.LocalJobRunner: map task executor complete.
15/03/17 11:17:46 INFO mapred.CopyCommitter: Remove parent: null for hdfs://localhost/
15/03/17 11:17:46 WARN mapred.CopyCommitter: Unable to cleanup temp files
java.lang.NullPointerException
	at org.apache.hadoop.fs.Path.<init>(Path.java:104)
	at org.apache.hadoop.fs.Path.<init>(Path.java:93)
	at org.apache.hadoop.tools.mapred.CopyCommitter.deleteAttemptTempFiles(CopyCommitter.java:141)
	at org.apache.hadoop.tools.mapred.CopyCommitter.cleanupTempFiles(CopyCommitter.java:130)
	at org.apache.hadoop.tools.mapred.CopyCommitter.commitJob(CopyCommitter.java:83)
	at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:538)
15/03/17 11:17:46 INFO mapred.CopyCommitter: Cleaning up temporary work folder: file:/tmp/hadoop/mapred/staging/lei2046334351/.staging/_distcp-1889397390
15/03/17 11:17:47 INFO mapreduce.Job: Job job_local992233322_0001 running in uber mode : false
15/03/17 11:17:47 INFO mapreduce.Job:  map 100% reduce 0%
15/03/17 11:17:47 INFO mapreduce.Job: Job job_local992233322_0001 completed successfully
15/03/17 11:17:47 INFO mapreduce.Job: Counters: 22
	File System Counters
		FILE: Number of bytes read=103917
		FILE: Number of bytes written=363277
		FILE: Number of read operations=0
		FILE: Number of large read operations=0
		FILE: Number of write operations=0
		HDFS: Number of bytes read=0
		HDFS: Number of bytes written=0
		HDFS: Number of read operations=8
		HDFS: Number of large read operations=0
		HDFS: Number of write operations=0
	Map-Reduce Framework
		Map input records=1
		Map output records=1
		Input split bytes=151
		Spilled Records=0
		Failed Shuffles=0
		Merged Map outputs=0
		GC time elapsed (ms)=14
		Total committed heap usage (bytes)=163577856
	File Input Format Counters
		Bytes Read=252
	File Output Format Counters
		Bytes Written=70
	org.apache.hadoop.tools.mapred.CopyMapper$Counter
		BYTESSKIPPED=23491
		SKIP=1

The distcp task can still success.

Issue Links

• relates to: HADOOP-5673 DistCp throw NPE if src is root