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From Ted Yu <yuzhih...@gmail.com>
Subject Re: Region Server is starting normally even if clock skew is more than default 30 seconds(or any configured). -> Regionserver node time is greater than master node time
Date Wed, 06 Nov 2013 14:20:42 GMT
Nice finding. 

Cheers

On Nov 6, 2013, at 6:11 AM, Kashif Jawed Siddiqui <kashifjs@huawei.com> wrote:

> Hi,
> 
> 
> 
>    When Region server's time is ahead of Master's time and the difference is more than
hbase.master.maxclockskew value, region server startup is not failing with ClockOutOfSyncException.
> 
> 
> 
>    ServerManager.java#checkClockSkew
> 
> 
> 
>          long skew = System.currentTimeMillis() - serverCurrentTime;
>        if (skew > maxSkew) {
>          String message = "Server " + serverName + " has been " +
>            "rejected; Reported time is too far out of sync with master.  " +
>            "Time difference of " + skew + "ms > max allowed of " + maxSkew + "ms";
>          LOG.warn(message);
>          throw new ClockOutOfSyncException(message);
>        }
> 
> 
> 
>    Above line results in negative value when Master's time is lesser than region server
time and  " if (skew > maxSkew) " check fails to find the skew in this case.
> 
> 
> 
>    I will be raising an Issue in JIRA for fixing the same. Please let me know if any
concerns.
> 
> 
> 
>    Please Note: This was tested in hbase 0.94.11 version and the trunk also currently
has the same logic.
> 
> 
> 
> Regards,
> Kashif Jawed Siddiqui
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