That's something I think we cut out of the slider code a while back,
probably before  slider 0.50

It was added so that we could work with versions of Hadoop that didn't have
working support for the YARN AM restart feature didn't try to use it.

Prior to Hadoop 2.4, the fields to enable it weren't in the code the client
used to request the feature, or in the data that came back from YARN when
the AM Started. We used reflection to try to load the methods if they
weren't there. For extra fun, the method could be in the hadoop JARs on the
client, but not on the server, and as we were using the pre-installed
hadoop JARs on the server, we could end up setting the option on the
client, but not have it do anything.

I think the flag was there to tell the tests whether or not the feature was
present in the destination cluster, so whether to run tests to kill the AM
and expect it to come back up *retaining the existing containers* —that is,
if the AM could be restarted without the running application noticing.

Everything works on Hadoop 2.6, so the option is gone, tests do kill the AM
and expect it come back (there's a "slider am-suicide" command for testing
this).

There's a property "slider.yarn.restart.limit" which sets a limit on how
many times slider should ask to restart; if unset you get the YARN limit
defined by "yarn.resourcemanager.am.max-retries" (plus some windowing
feature which handles intermittent timeouts over a long running service).
Set it to 1 and should say "no restarts" (i.e. one attempt to run slider is
made -the first)

It's covered in the
http://slider.incubator.apache.org/docs/client-configuration.html docs

-steve



On 12 December 2014 at 11:41, 杨浩 <[email protected]> wrote:

> How to configure the configuration? When set false, sometimes it works, and
> sometimes not.
>

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