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https://issues.apache.org/jira/browse/HADOOP-10794?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zhijie Shen updated HADOOP-10794:
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Description:
As a distributed system, a hadoop cluster wants the clock on all the
participating hosts synchronized. Otherwise, some problems might happen. For
example, in YARN-2251, due to the clock on the host for the task container
falls behind that on the host of the AM container, the computed elapsed time
(the diff between the timestamps produced on two hosts) becomes negative.
In YARN-2251, we tried to mask the negative elapsed time. However, we should
seek for a decent long term solution, such as providing mechanism to do and
check clock synchronization.
was:
As a distributed system, a hadoop cluster wants the clock on all the
participating hosts synchronized. Otherwise, some problems might happen. For
example, in MAPREDUCE-5940, due to the clock on the host for the task container
falls behind that on the host of the AM container, the computed elapsed time
(the diff between the timestamps produced on two hosts) becomes negative.
In MAPREDUCE-5940, we tried to mask the negative elapsed time. However, we
should seek for a decent long term solution, such as providing mechanism to do
and check clock synchronization.
> A hadoop cluster needs clock synchronization
> --------------------------------------------
>
> Key: HADOOP-10794
> URL: https://issues.apache.org/jira/browse/HADOOP-10794
> Project: Hadoop Common
> Issue Type: Bug
> Reporter: Zhijie Shen
>
> As a distributed system, a hadoop cluster wants the clock on all the
> participating hosts synchronized. Otherwise, some problems might happen. For
> example, in YARN-2251, due to the clock on the host for the task container
> falls behind that on the host of the AM container, the computed elapsed time
> (the diff between the timestamps produced on two hosts) becomes negative.
> In YARN-2251, we tried to mask the negative elapsed time. However, we should
> seek for a decent long term solution, such as providing mechanism to do and
> check clock synchronization.
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