[HDFS-14468] StorageLocationChecker methods throw DiskErrorExceptions when the configuration has wrong values

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Haicheng Chen
• Created: 06/May/19 13:47
• Updated: 29/May/19 18:06
• Resolved: 29/May/19 18:06

Description

Dear HDFS developers, we are developing a tool to detect exception-related bugs in Java. Our prototype has spotted the following three throw statements whose exception class and error message indicate different error conditions.

 

Version: Hadoop-3.1.2

File: HADOOP-ROOT/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/checker/StorageLocationChecker.java

Line: 96-98, 110-113, and 173-176

throw new DiskErrorException("Invalid value configured for "
    + DFS_DATANODE_DISK_CHECK_TIMEOUT_KEY + " - "
    + maxAllowedTimeForCheckMs + " (should be > 0)");

throw new DiskErrorException("Invalid value configured for "
    + DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY + " - "
    + maxVolumeFailuresTolerated + " "
    + DataNode.MAX_VOLUME_FAILURES_TOLERATED_MSG);

throw new DiskErrorException("Invalid value configured for "
    + DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY + " - "
    + maxVolumeFailuresTolerated + ". Value configured is >= "
    + "to the number of configured volumes (" + dataDirs.size() + ").");

 

A DiskErrorException means an error has occurred when the process is interacting with the disk, e.g., in org.apache.hadoop.util.DiskChecker.checkDirInternal() we have the following code (lines 97-98):

throw new DiskErrorException("Cannot create directory: " + dir.toString());

However, the error messages of the first three exceptions indicate that the StorageLocationChecker is configured incorrectly, which means there is nothing wrong with the disk (yet). This mismatch could be a problem. For example, the callers trying to handle other DiskErrorException may accidentally (and incorrectly) handle the configuration error.