[AMBARI-10143] DataNode fails to start because of lowercase conversion of data dir path in data_dir_mount_file.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.0
• Fix Version/s: 2.1.0
• Component/s: ambari-agent

Environment

Ubuntu 12.04 x64

• Assignee: Alejandro Fernandez
• Reporter: Paulo Tioseco
• Created: 19/Mar/15 23:27
• Updated: 20/Mar/15 23:06
• Resolved: 20/Mar/15 20:19

Description

The code that handles creating the data dir and reading data_dir_mount_file explicitly converts the data dir paths to lower case.

This behavior is undesired because when the value of dfs.datanode.data.dir contains one or more uppercase characters, it won't be able to match any item in the data_dir_mount_file since Linux file paths are case sensitive.

The issue may be reproduced by creating a single node cluster and setting the value of the "DataNode directories" in "CLUSTER INSTALL WIZARD > Customize Services > HDFS > DataNode" to: /UPPER_CASE_DIR/data

Continue to the next step and the "DataNode start" task will fail with the following exception (from /var/log/hadoop/hdfs/hadoop-hdfs-datanode-*.log):

datanode.DataNode (DataNode.java:checkStorageLocations(2284)) - Invalid dfs.datanode.data.dir /UPPER_CASE_DIR/data :
java.io.FileNotFoundException: File file:/UPPER_CASE_DIR/data does not exist

The checkStorageLocations function won't be able to find the directory because the directory name was created with all lower case characters (from /var/lib/ambari-agent/data/output-9.txt):

Forcefully creating directory: /upper_case_dir/data

The data_dir_mount_file and hdfs-site.xml also shows the case mismatch of the data dir path:

$ grep -rni UPPER_CASE_DIR /etc/hadoop/
/etc/hadoop/conf.empty/hdfs-site.xml:46:      <value>/UPPER_CASE_DIR/data</value>
/etc/hadoop/conf.empty/dfs_data_dir_mount.hist:7:/upper_case_dir/data,/
/etc/hadoop/conf/hdfs-site.xml:46:      <value>/UPPER_CASE_DIR/data</value>
/etc/hadoop/conf/dfs_data_dir_mount.hist:7:/upper_case_dir/data,/

Issue Links

• relates to: AMBARI-7506 Ambari DataNode shouldn't create dfs.data.dir paths after installation when path becomes unmounted