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Posted to dev@hbase.apache.org by Kashif Jawed Siddiqui <ka...@huawei.com> on 2013/11/06 15:11:36 UTC

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

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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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

Posted by Ted Yu <yu...@gmail.com>.
Nice finding. 

Cheers

On Nov 6, 2013, at 6:11 AM, Kashif Jawed Siddiqui <ka...@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
> ***************************************************************************************
> This e-mail and attachments contain confidential information from HUAWEI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient's) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!