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From Rohith Sharma K S <rohithsharm...@apache.org>
Subject Re: [VOTE] Release Apache Hadoop 3.0.0 RC0
Date Thu, 30 Nov 2017 09:07:51 GMT
Hi Vinod/Allen

bq. We need to figure out if this V1 TimelineService should even be support
given ATSv2.
ATSv2 is in alpha phase. We should continue to support Timeline Service V1
till we have the detailed entity level ACLs in V2. And also there are
proposal to upgrade/migration paths from TSv1 to TSv2.

bq. If ATSv1 isn’t replaced by ATSv2, then why is it marked deprecated?
Ideally it should not be. Can you point out where it is marked as
deprecated? If it is in historyserver daemon start, that change made very
long back when timeline server added.

Thanks & Regards
Rohith Sharma K S

On 26 November 2017 at 03:28, Allen Wittenauer <aw@effectivemachines.com>
wrote:

>
> > On Nov 21, 2017, at 2:16 PM, Vinod Kumar Vavilapalli <vinodkv@apache.org>
> wrote:
> >
> >>> - $HADOOP_YARN_HOME/sbin/yarn-daemon.sh start historyserver doesn't
> even work. Not just deprecated in favor of timelineserver as was advertised.
> >>
> >>      This works for me in trunk and the bash code doesn’t appear to
> have changed in a very long time.  Probably something local to your
> install.  (I do notice that the deprecation message says “starting” which
> is awkward when the stop command is given though.)  Also: is the
> deprecation message even true at this point?
> >
> >
> > Sorry, I mischaracterized the problem.
> >
> > The real issue is that I cannot use this command line when the MapReduce
> JobHistoryServer is already started on the same machine.
>
>         The specific string is:
>
>         hadoop-${HADOOP_IDENT_STRING}-${HADOOP_SUBCMD}.pid
>
>         More specifically, the pid handling code will conflict if the
> following are true:
>
>                 * same machine (obviously)
>                 * same subcommand name
>                 * same HADOOP_IDENT_USER: which by default is the user
> name of whatever starts it… but was designed to be overridden way back in
> hadoop 0.X.
>
>         … which means for most production setups, this is probably not
> real a problem.
>
>
> > So, it looks like in shell-scripts, there can ever be only one daemon of
> a given name, irrespective of which daemon scripts are invoked.
>
>         Correct.  Naming multiple, different daemons the same thing is
> extremely anti-user.   In fact, I thought this was originally about the
> “other” history server.
>
> >
> > We need to figure out two things here
> >  (a) The behavior of this command. Clearly, it will conflict with the
> MapReduce JHS - only one of them can be started on the same node.
>
>         … by the same user, by default.  Started by a different user or
> different HADOOP_IDENT_USER, it will come up just fine.
>
> >  (b) We need to figure out if this V1 TimelineService should even be
> support given ATSv2.
>
>         If ATSv1 isn’t replaced by ATSv2, then why is it marked deprecated?
>
> > On Nov 22, 2017, at 9:45 AM, Brahma Reddy Battula <brahma@apache.org>
> wrote:
> >
> > 1) Change the name
> > 2) Create PID based on the CLASS Name, here applicationhistoryserver and
> jobhistoryserver
> > 3) Use same as branch-2.9..i.e suffixing with mapred or yarn
> >
> >
> > @allen, any thoughts on this..?
>
>         Using the classname works in this instance, but just as we saw
> with the router daemons, people tend to use the same class names when
> building different components. It also means that if different daemons can
> be started in different ways from the same class dependent upon options,
> this conflict will still exist.  Also, with dynamic commands, it is very
> possible to run the same daemon from multiple start points.
>
>         As part of this discussion, I think it’s important to recognize:
>
> a) This is likely to be primarily impacting developers.
> b) We’re talking about two daemons where one has been deprecated.
> c) Calling two different daemons “history server” is just awful from an
> end user perspective.
> d) There is already a work around in place if one absolutely needs to run
> both on the same node as the same user, just as people do with datanode and
> nodemanager today.
>
>
>
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