and please remember, i stated that although the hadoop cluster uses NTP, the "server" (the machine that is not a part of the hadoop cluster) cannot assume to be using NTP (and in fact, doesn't).
On Fri, May 17, 2013 at 10:10 AM, Jane Wayne <jane.wayne2...@gmail.com>wrote: > "if NTP is correclty used" > > that's the key statement. in several of our clusters, NTP setup is kludgy. > note that the professionals administering the cluster are different from > "us" the engineers. so, there's a lot of red tape to go through to get > something trivial or not fixed. we have noticed that NTP is not setup > correctly (using default GMT timezone, for example). without explaining all > the tedious details, this mismatch of date/time (of the hadoop cluster to > the server machine) is causing some pains. > > i'm not sure i agree with "the local OS time from your server machine will > be the best estimation." that doesn't make sense. > > but what i want to achieve is very simple. as stated before, i just want > to ask the namenode or jobtracker, "hey, what date/time do you have?" > unfortunately for me, as niels pointed out, this query is not possible via > the hadoop api. > > thanks for helping, though. > > :) > > > On Fri, May 17, 2013 at 10:02 AM, Bertrand Dechoux <decho...@gmail.com>wrote: > >> For hadoop, 'cluster time' is the local OS time. You might want to get the >> time of the namenode machine but indeed if NTP is correctly used, the >> local >> OS time from your server machine will be the best estimation. If you >> request the time from the namenode machine, you will be penalized by the >> delay of your request. >> >> Regards >> >> Bertrand >> >> >> On Fri, May 17, 2013 at 3:17 PM, Niels Basjes <ni...@basjes.nl> wrote: >> >> > Hi, >> > >> > > i have another computer (which i have referred to as a server, since >> it >> > is >> > > running tomcat), and this computer is NOT a part of the hadoop cluster >> > (it >> > > doesn't run any of the hadoop daemons), but does submit jobs to the >> > hadoop >> > > cluster via a JEE webapp interface. i need to check that the time on >> this >> > > computer is in sync with the time on the hadoop cluster. when i say >> > "check >> > > that the time is in sync", there is a defined tolerance/threshold >> > > difference in date/time that i am willing to accept (e.g. the >> date/time >> > > should be the same down to the minute). >> > >> > If you ensure (using NTP) that all your servers have the same time then >> you >> > can simply query your local server for the time and you have the correct >> > answer to your question. >> > >> > You are searching for a solution in the Hadoop API (where this does not >> > exist) when the solution is present at a different level. >> > >> > -- >> > Best regards / Met vriendelijke groeten, >> > >> > Niels Basjes >> > >> > >
