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Posted to common-issues@hadoop.apache.org by "Chris Nauroth (JIRA)" <ji...@apache.org> on 2013/08/09 21:47:47 UTC
[jira] [Updated] (HADOOP-9857) Tests block and sometimes timeout on
Windows due to invalid entropy source.
[ https://issues.apache.org/jira/browse/HADOOP-9857?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Nauroth updated HADOOP-9857:
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Attachment: HADOOP-9857.1.patch
Here is a patch to use {{file:/dev/urandom}} when running on Windows. Note that this doesn't mean we actually attempt to open a file at that path on Windows. (See earlier comment for explanation of how the JVM does a string match on this value to determine whether or not to use a native entropy implementation.) Since comments in the earlier jiras said that {{file:/dev/urandom}} didn't work correctly on Linux, I hid this behind a Windows-specific Maven profile, so we'll keep using {{file:///dev/urandom}} on Linux and only use {{file:/dev/urandom}} on Windows.
> Tests block and sometimes timeout on Windows due to invalid entropy source.
> ---------------------------------------------------------------------------
>
> Key: HADOOP-9857
> URL: https://issues.apache.org/jira/browse/HADOOP-9857
> Project: Hadoop Common
> Issue Type: Bug
> Components: build, test
> Affects Versions: 3.0.0, 2.1.1-beta
> Reporter: Chris Nauroth
> Assignee: Chris Nauroth
> Attachments: HADOOP-9857.1.patch
>
>
> Tests are configured to set the entropy source to {{file:///dev/urandom}} to prevent blocking on machines with low entropy. We've observed that on Windows, this will cause tests to block for 5 seconds trying to access this non-existent path the first time the process does something that needs entropy, such as using a {{SecureRandom}} or creating a {{UUID}}. This can cause tests to fail due to timeouts. In addition to the initial 5-second blocking, this causes the JVM to fall back to a slower, non-native seed generation implementation.
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