[HDFS-7255] Customize Java Heap min/max settings for individual processes

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.4.1, 2.5.1
• Component/s: datanode, journal-node, namenode
• Labels: datanode heap java journalnode namenode zkfc
• Tags: namenode datanode zkfc journalnode java heap min max
• Assignee: Unassigned
• Reporter: Mark Tse
• Created: 16/Oct/14 18:22
• Updated: 16/Oct/14 18:22

Description

The NameNode and JournalNode (and ZKFC) can all run on the same machine. However, they get their heap settings from HADOOP_HEAPSIZE/JAVA_HEAP_MAX. There are scenarios where the NameNode process should have different Java memory requirements than the JournalNode and ZKFC (e.g. if the machine has 10 GB of RAM, and I want the NameNode process to have 8 GB max).

HADOOP_(.*)_OPTS variables exist for these processes and can be used to add the Xms and Xmx tags, but because of how the default for JAVA_HEAP_MAX is set, it will always add '-Xmx1000m' to the final call to start up the NameNode/JournalNode/ZKFC process, resulting in two different Java heap settings (e.g. -Xmx1000m and -Xmx8g is used when starting the NameNode).

Note: HADOOP_HEAPSIZE is deprecated according to HADOOP-10950