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https://issues.apache.org/jira/browse/HADOOP-13717?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15576304#comment-15576304
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Allen Wittenauer commented on HADOOP-13717:
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bq. it seems like if someone is not specifying the "--daemon" flag, then they
don't care about daemon things like pid files and log dirs for stdout/stderr.
They do, actually. The inconsistent behavior of the hadoop daemons was a big
sticking point amongst quite a few admins I had talked to.
bq. The audit log is an interesting case, but I think app-specific logging
should be checked in the app, not the shell scripts (which are generic).
I'd love to see pid and log dir handling out of the scripts. It greatly
over-complicates them. One thing to keep in mind that doing it prior to Java
launch means that we get extremely fast fail: there's no Java classpath work
and no Java initialization costs.
bq. Bigtop and CDH don't have balancer init scripts for instance.
Sorry, I think I may have miscommunicated this point. start-balancer is geared
towards manual usage but running it in the background and catching it's IO as
it can run for very long times on large and/or extremely misbalanced clusters.
It's not a daemon in the traditional sense. It really is a convience script
so that those that aren't familiar with bash don't have to remember how to
catch stdout/stderr, or use disown or whatever. I'd be very surprised if
there actually was an init script.
It's fun to note that the start-balancer script only appears to be documented
in the Balancer javadoc and the only place that Javadoc is really exposed is on
Cloudera's website. ;)
bq. I think there should be some generic fix for when "--daemon" isn't
specified, because of user expectations.
As stated above, user expectation is consistency. No consistency will mean
we'll also need to remove the --daemon status capability since it will be
unreliable.
> Shell scripts call hadoop_verify_logdir even when command is not started as
> daemon
> ----------------------------------------------------------------------------------
>
> Key: HADOOP-13717
> URL: https://issues.apache.org/jira/browse/HADOOP-13717
> Project: Hadoop Common
> Issue Type: Bug
> Components: scripts
> Affects Versions: 3.0.0-alpha1
> Reporter: Andrew Wang
>
> Issue found when working with the HDFS balancer.
> In {{hadoop_daemon_handler}}, it calls {{hadoop_verify_logdir}} even for the
> "default" case which calls {{hadoop_start_daemon}}. {{daemon_outfile}} which
> specifies the log location isn't even used here, since the command is being
> started in the foreground.
> I think we can push the {{hadoop_verify_logdir}} call down into
> {{hadoop_start_daemon_wrapper}} instead, which does use the outfile.
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