[ https://issues.apache.org/jira/browse/HADOOP-7335?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13042504#comment-13042504 ] 

Todd Lipcon commented on HADOOP-7335:
-------------------------------------

Yea, I just tried changing my environment to file:/dev/urandom and it doesn't work correctly - I see Jetty hanging at startup. jstack shows it trying to read entropy. If I use file:///dev/urandom as I did in this patch, it starts immediately every time.

> Force entropy to come from non-true random for tests
> ----------------------------------------------------
>
>                 Key: HADOOP-7335
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7335
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: build, test
>    Affects Versions: 0.22.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>            Priority: Minor
>         Attachments: hadoop-7335.txt
>
>
> Passing the system property {{-Djava.security.egd=file:///dev/urandom}} forces the JVM to seed its PRNG from non-true random (/dev/urandom) instead of the true random (/dev/random). This makes the tests run faster, since without it they often hang waiting for entropy while Jetty is initializing.
> We should turn this on for the test targets by default, so developers/hudson boxes don't have to make this change system-wide or use workarounds like rngtools.

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