[jira] [Commented] (HADOOP-10993) Dump java command line to *.out file

["Allen Wittenauer (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-10993?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14223475#comment-14223475 ] 

Allen Wittenauer commented on HADOOP-10993:
-------------------------------------------

Since this was filed, the --debug option has been added which effectively does this feature:

{code}
function hadoop_java_exec
{
  # run a java command.  this is used for
  # non-daemons

  local command=$1
  local class=$2
  shift 2

  hadoop_debug "Final CLASSPATH: ${CLASSPATH}"
  hadoop_debug "Final HADOOP_OPTS: ${HADOOP_OPTS}"

  export CLASSPATH
  #shellcheck disable=SC2086
  exec "${JAVA}" "-Dproc_${command}" ${HADOOP_OPTS} "${class}" "$@"
}
{code}

... and similar code in the *_daemon equivalents. 

At the time, I opted not to put the entire java command line because:
* The entire command line is exceedingly long.  It pretty much requires breaking it up for readability.
* The CLASSPATH and HADOOP_OPTS are significantly more interesting than the class and arguments 99% of the time

So that leaves a few things that should probably added to the --debug output for this JIRA:
* JAVA_HOME and/or JAVA
* command line options
* class name


So these days, we should probably log 

> Dump java command line to *.out file
> ------------------------------------
>
>                 Key: HADOOP-10993
>                 URL: https://issues.apache.org/jira/browse/HADOOP-10993
>             Project: Hadoop Common
>          Issue Type: Improvement
>            Reporter: Allen Wittenauer
>            Assignee: Sankara Reddy Telukutla
>            Priority: Minor
>              Labels: newbie
>
> It might be a nice enhancement to print the contents of the java command line to the out file during daemon startup to help with debugging.



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