hadoop-common-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Zhijie Shen (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HADOOP-10794) A hadoop cluster needs clock synchronization
Date Tue, 08 Jul 2014 07:39:33 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-10794?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Zhijie Shen updated HADOOP-10794:
---------------------------------

    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.



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message