2016-09-23 12:38 GMT+08:00 Devaraj Das <d...@hortonworks.com>: > Guys, first off apologies for bringing in the topic of MR-based > compactions.. But I was thinking more about the SpliceMachine approach of > managing compactions in Spark where apparently they saw a lot of benefits. > Apologies for giving you that sore throat Andrew; I really didn't mean to > :-) > > So on this issue, we have these on the plate: > 0. Somehow not use MR but something like that > 1. Run a standalone service other than master > 2. Shell out from the master > > I don't think we have a good answer to (0), and I don't think it's even > worth the effort of trying to build something when MR is already there, and > being used by HBase already for some operations. > > On (1), we have to deal with a myriad of issues - HA of the server not > being the least of them all. Security (kerberos authentication, another > keytab to manage, etc. etc. etc.). IMO, that approach is DOA. Instead let's > substitute that (1) with the HBase Master. I haven't seen any good reason > why the HBase master shouldn't launch MR jobs if needed. It's not ideal; > agreed. > > We have already put lots of stuffs in HMaster, especially on startup, we even need to run the initializations in a background thread to let the master get up quickly and causes lots of races. I do not think it is a good idea to keep messing up the code there. For MR, as I said above, configuration. I do not want to restart HMaster if I just want to tune the config of a backup MR job. Yes, you could introduce new shell commands to do that, change job config, change YARN cluster, and persist the change to some places, maybe zookeeper? Oh no...
> Now before going to (2), let's see what are the benefits of running the > backup/restore jobs from the master. I think Ted has summarized some of the > issues that we need to take care of - basically, the master can keep track > of running jobs, and should it fail, the backup master can continue keeping > track of it (since the jobId would have been recorded in the proc WAL). The > master can also do cleanup, etc. of failed backup/restore processes. > Security is another issue - the job needs to run as 'hbase' since it owns > the data. Having the master launch the job makes it get that privilege. In > the (2) approach, it's hard to do some of the above management. > > Guys, just to reiterate, the patch as such is ready from the overall > design/arch point of view (maybe code review is still pending from Matteo). > If in the future, we find better ways of doing this without using MR, we > can certainly consider that. But IMO don't think we should block this patch > from getting merged. > > ________________________________________ > From: 张铎 <palomino...@gmail.com> > Sent: Thursday, September 22, 2016 8:32 PM > To: dev@hbase.apache.org > Subject: Re: [DISCUSSION] MR jobs started by Master or RS > > So what about a standalone service other than master? You can use your own > procedure store in that service? > > 2016-09-23 11:28 GMT+08:00 Ted Yu <yuzhih...@gmail.com>: > > > An earlier implementation was client driven. > > > > But with that approach, it is hard to resume if there is error midway. > > Using Procedure V2 makes the backup / restore more robust. > > > > Another consideration is for security. It is hard to enforce security (to > > be implemented) for client driven actions. > > > > Cheers > > > > > On Sep 22, 2016, at 8:15 PM, Andrew Purtell <andrew.purt...@gmail.com> > > wrote: > > > > > > No, this misses Matteo's finer point, which is "shelling out" from the > > master directly to run MR is a first. Why not drive this with a utility > > derived from Tool? > > > > > > On Sep 22, 2016, at 7:57 PM, Vladimir Rodionov <vladrodio...@gmail.com > > > > wrote: > > > > > >>>> In our production cluster, it is a common case we just have HDFS > and > > >>>> HBase deployed. > > >>>> If our Master/RS depend on MR framework (especially some features we > > >>>> have not used at all), it introduced another cost for maintain. I > > >>>> don't think it is a good idea. > > >> > > >> So , you are not backup users in this case. Many our customers have > full > > >> stack deployed and > > >> want see backup to be a standard feature. Besides this, nothing will > > happen > > >> in your cluster > > >> if you won't be doing backups. > > >> > > >> This discussion (we do not want see M/R dependency) goes to nowhere. > We > > >> asked already, at least twice, to suggest another framework (other > than > > M/R) > > >> for bulk data copy with *conversion*. Still waiting for suggestions. > > >> > > >> -Vlad > > >> > > >> > > >> > > >> > > >>> On Thu, Sep 22, 2016 at 7:49 PM, Ted Yu <yuzhih...@gmail.com> wrote: > > >>> > > >>> If MR framework is not deployed in the cluster, hbase still functions > > >>> normally (post merge). > > >>> > > >>> In terms of build time dependency, we have long been depending on > > >>> mapreduce. Take a look at ExportSnapshot. > > >>> > > >>> Cheers > > >>> > > >>> On Thu, Sep 22, 2016 at 7:42 PM, Heng Chen <heng.chen.1...@gmail.com > > > > >>> wrote: > > >>> > > >>>> In our production cluster, it is a common case we just have HDFS > and > > >>>> HBase deployed. > > >>>> If our Master/RS depend on MR framework (especially some features we > > >>>> have not used at all), it introduced another cost for maintain. I > > >>>> don't think it is a good idea. > > >>>> > > >>>> 2016-09-23 10:28 GMT+08:00 张铎 <palomino...@gmail.com>: > > >>>>> To be specific, for example, our nice Backup/Restore feature, if we > > >>> think > > >>>>> this is not a core feature of HBase, then we could make it depend > on > > >>> MR, > > >>>>> and start a standalone BackupManager instance that submits MR jobs > to > > >>> do > > >>>>> periodical maintenance job. And if we think this is a core feature > > that > > >>>>> everyone should use it, then we'd better implement it without MR > > >>>>> dependency, like DLS. > > >>>>> > > >>>>> Thanks. > > >>>>> > > >>>>> 2016-09-23 10:11 GMT+08:00 张铎 <palomino...@gmail.com>: > > >>>>> > > >>>>>> I‘m -1 on let master or rs launch MR jobs. It is OK that some of > our > > >>>>>> features depend on MR but I think the bottom line is that we > should > > >>>> launch > > >>>>>> the jobs from outside manually or by other services. > > >>>>>> > > >>>>>> 2016-09-23 9:47 GMT+08:00 Andrew Purtell < > andrew.purt...@gmail.com > > >: > > >>>>>> > > >>>>>>> Ok, got it. Well "shelling out" is on the line I think, so a fair > > >>>>>>> question. > > >>>>>>> > > >>>>>>> Can this be driven by a utility derived from Tool like our other > MR > > >>>> apps? > > >>>>>>> The issue is needing the AccessController to decide if allowed? > But > > >>>> nothing > > >>>>>>> prevents the user from running the job manually/independently, > > right? > > >>>>>>> > > >>>>>>>> On Sep 22, 2016, at 3:44 PM, Matteo Bertozzi < > > >>>> theo.berto...@gmail.com> > > >>>>>>> wrote: > > >>>>>>>> > > >>>>>>>> just a remark. my query was not about tools using MR (everyone i > > >>>> think > > >>>>>>> is > > >>>>>>>> ok with those). > > >>>>>>>> the topic was about: "are we ok with running MR jobs from Master > > >>> and > > >>>> RSs > > >>>>>>>> code?" since this will be the first time we do this > > >>>>>>>> > > >>>>>>>> Matteo > > >>>>>>>> > > >>>>>>>> > > >>>>>>>>> On Thu, Sep 22, 2016 at 2:49 PM, Devaraj Das < > > >>> d...@hortonworks.com> > > >>>>>>> wrote: > > >>>>>>>>> > > >>>>>>>>> Very much agree; for tools like ExportSnapshot / Backup / > > Restore, > > >>>> it's > > >>>>>>>>> fine to be dependent on MR. MR is the right framework for such. > > We > > >>>>>>> should > > >>>>>>>>> also do compactions using MR (just saying :) ) > > >>>>>>>>> ________________________________________ > > >>>>>>>>> From: Ted Yu <yuzhih...@gmail.com> > > >>>>>>>>> Sent: Thursday, September 22, 2016 2:00 PM > > >>>>>>>>> To: dev@hbase.apache.org > > >>>>>>>>> Subject: Re: [DISCUSSION] MR jobs started by Master or RS > > >>>>>>>>> > > >>>>>>>>> I agree - backup / restore is in the same category as import / > > >>>> export. > > >>>>>>>>> > > >>>>>>>>> On Thu, Sep 22, 2016 at 1:58 PM, Andrew Purtell < > > >>>>>>> andrew.purt...@gmail.com> > > >>>>>>>>> wrote: > > >>>>>>>>> > > >>>>>>>>>> Backup is extra tooling around core in my opinion. Like import > > or > > >>>>>>> export. > > >>>>>>>>>> Or the optional MOB tool. It's fine. > > >>>>>>>>>> > > >>>>>>>>>>> On Sep 22, 2016, at 1:50 PM, Matteo Bertozzi < > > >>>> mberto...@apache.org> > > >>>>>>>>>> wrote: > > >>>>>>>>>>> > > >>>>>>>>>>> What's the latest opinion around running MR jobs from hbase > > >>>> (Master > > >>>>>>> or > > >>>>>>>>>> RS)? > > >>>>>>>>>>> > > >>>>>>>>>>> I remember in the past that there was discussion about not > > >>> having > > >>>> MR > > >>>>>>>>> has > > >>>>>>>>>>> direct dependency of hbase. > > >>>>>>>>>>> > > >>>>>>>>>>> I think some of discussion where around MOB that had a MR job > > to > > >>>>>>>>> compact, > > >>>>>>>>>>> that later was transformed in a non-MR job to be merged, I > > think > > >>>> we > > >>>>>>>>> had a > > >>>>>>>>>>> similar discussion for log split/replay. > > >>>>>>>>>>> > > >>>>>>>>>>> the latest is the new Backup feature (HBASE-7912), that runs > a > > >>> MR > > >>>> job > > >>>>>>>>>> from > > >>>>>>>>>>> the master to copy data or restore data. > > >>>>>>>>>>> (backup is also "not really core" as in.. if you don't use > > >>> backup > > >>>>>>>>> you'll > > >>>>>>>>>>> not end up running MR jobs, but this was probably true for > MOB > > >>> as > > >>>> in > > >>>>>>>>> "if > > >>>>>>>>>>> you don't enable MOB you don't need MR") > > >>>>>>>>>>> > > >>>>>>>>>>> any thoughts? do we a rule that says "we don't want to have > > >>> hbase > > >>>> run > > >>>>>>>>> MR > > >>>>>>>>>>> jobs, only tool started manually by the user can do that". or > > >>> can > > >>>> we > > >>>>>>>>>> start > > >>>>>>>>>>> adding MR calls around without problems? > > >>> > > >
