[jira] [Updated] (AMBARI-14050) Produce a Warning When Jetty Pool Size Is Too Low And Increase It

["Jonathan Hurley (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMBARI-14050?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Hurley updated AMBARI-14050:
-------------------------------------
    Attachment: AMBARI-14050.patch

> Produce a Warning When Jetty Pool Size Is Too Low And Increase It
> -----------------------------------------------------------------
>
>                 Key: AMBARI-14050
>                 URL: https://issues.apache.org/jira/browse/AMBARI-14050
>             Project: Ambari
>          Issue Type: Bug
>          Components: ambari-server
>    Affects Versions: 2.0.0
>            Reporter: Jonathan Hurley
>            Assignee: Jonathan Hurley
>            Priority: Critical
>             Fix For: 2.1.3
>
>         Attachments: AMBARI-14050.patch
>
>
> Ambari's default Jetty thread pool is configured at 25 threads. When deployed on a machine that has 48 "processors", Jetty's calculation for determining how many "Acceptor" and "Selector" threads to create never takes into account the core pool size. As a result, we get:
> - 12 "Acceptor" threads (these answer binds to port 8080)
> - 12 "Selector" threads (these pick available threads to answer bindings)
> - 1 free thread (these are the threads available to do stuff with)
> Notice that there's only 1 free thread. This means that Jetty effectively makes Ambari a single-threaded web application on larger systems!
> The "fix" is to increase the thread count in the {{ambari.properties}}, however nobody knows to do this since no warning is produced.
> I suggest:
> - Log a warning on server startup if we detect that the core pool size is less than 3/4 of the available processors on the system.
> - Automatically increase the core pool size to the min(100, double existing size) when the above is detected



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