Hi, Are these bare metal nodes or VMs?
For VMs I suggest you just attach rbd data disks then let hdfs do it’s magic. Just make sure you’re not replicating 9x (3x on ceph + 3x on hadoop). If it’s VMs, you can just do the same with krbd, just make sure to run a recent enough kernel :-) Basically putting HDFS on RBDs. > On 05 Feb 2016, at 13:42, Jose M <soloning...@hotmail.com > <mailto:soloning...@hotmail.com>> wrote: > > Hi Zoltan, thanks for the answer. > > Because replacing hdfs:// with ceph:// and use CephFs doesn't work for all > haddop componentes out of the box (unless in my tests), for example I had > issues with Hbase, then with Yarn, Hue, etc (I'm using the cloudera > distribution but I also tried with separate components). And besides the need > to add jars and bindings to each node to get them work, there are a lot of > places (xmls, configuration) where the "hdfs for ceph" replacement need to be > made. > > Giving this issues, I thought that mounting ceph as a local directory and > then use this "virtual dirs" as the haddop dfs dirs, would be easier and will > work better (less configuration problems, and only changing the dfs dirs will > make all components work without any more changes). > > Of course I can be totally wrong, and it's a core change to do this, that's > why I think I should ask here first :) > > Thanks! > > PS: If you are asking why I'm trying to use ceph here, well it's because we > were given an infrastructure with the possibility yo use a big ceph storage > that's working really really well (but as an object store and wasn't use > until now with hadoop). > > > De: Zoltan Arnold Nagy <zol...@linux.vnet.ibm.com > <mailto:zol...@linux.vnet.ibm.com>> > Enviado: jueves, 04 de febrero de 2016 06:07 p.m. > Para: John Spray > Cc: Jose M; ceph-users@lists.ceph.com <mailto:ceph-users@lists.ceph.com> > Asunto: Re: [ceph-users] Ceph and hadoop (fstab insted of CephFS) > > Might be totally wrong here, but it’s not layering them but replacing hdfs:// > URLs with ceph:// URLs so all the mapreduce/spark/hbase/whatever is on top > can use CephFS directly which is not a bad thing to do (if it works) :-) > >> On 02 Feb 2016, at 16:50, John Spray <jsp...@redhat.com >> <mailto:jsp...@redhat.com>> wrote: >> >> On Tue, Feb 2, 2016 at 3:42 PM, Jose M <soloning...@hotmail.com >> <mailto:soloning...@hotmail.com>> wrote: >>> Hi, >>> >>> >>> One simple question, in the ceph docs says that to use Ceph as an HDFS >>> replacement, I can use the CephFs Hadoop plugin >>> (http://docs.ceph.com/docs/master/cephfs/hadoop/ >>> <http://docs.ceph.com/docs/master/cephfs/hadoop/>). >>> >>> >>> What I would like to know if instead of using the plugin, I can mount ceph >>> in fstab and then point hdfs dirs (namenode, datanode, etc) to this mounted >>> "ceph" dirs, instead of native local dirs. >>> >>> I understand that maybe will involve more configuration steps (configuring >>> fstab in each node), but will this work? Is there any problem with this type >>> of configuration? >> >> Without being a big HDFS expert, it seems like you would be >> essentially putting one distributed filesystem on top of another >> distributed filesystem. I don't know if you're going to find anything >> that breaks as such, but it's probably not a good idea. >> >> John >> >>> >>> Thanks in advance, >>> >>> >>> >>> _______________________________________________ >>> ceph-users mailing list >>> ceph-users@lists.ceph.com <mailto:ceph-users@lists.ceph.com> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>> <http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com> >>> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@lists.ceph.com <mailto:ceph-users@lists.ceph.com> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> <http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com>
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