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Hadoop, mail # user - Question about HA and Federation


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ESGLinux 2012-12-20, 16:30
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Harsh J 2012-12-20, 17:12
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ESGLinux 2012-12-20, 17:39
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Harsh J 2012-12-20, 17:48
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Re: Question about HA and Federation
ESGLinux 2012-12-20, 17:55
Hi again,

So finally the number of nodes are these:

1 Active NameNode + 1 Passive NameNode (it does the work of the
old Secondary NameNode) for NS1 NameSpace (these are 2 diferent machines)
1 NameNode for NS2 + 1 Secondary NameNode
1 NameNode for NS3 + 1 Secondary NameNode

We can say that we need 2 nodes per NameSpace, is that true?

Thanks,

ESGLinux

2012/12/20 Harsh J <[EMAIL PROTECTED]>

> Hi,
>
> To put it simply: If you use a NameNode, you need a SecondaryNameNode.
> In HA-mode, a StandbyNameNode acts as a SecondaryNameNode (so you
> don't need to run an extra).
>
> Either way, you definitely need the checkpoint operation happening and
> being monitored for.
>
> On Thu, Dec 20, 2012 at 11:09 PM, ESGLinux <[EMAIL PROTECTED]> wrote:
> > Hi Harsh,
> >
> > First thank you very much for your answer,
> >
> > following your example:
> >
> > You have:
> >
> > 1 Active NameNode + 1 Passive NameNode (it does the work of the old
> > Secondary NameNode) for NS1 NameSpace (these are 2 diferent machines)
> > 1 NameNode for NS2
> > 1 NameNode for NS3
> >
> > but what about the Secondary Name Nodes for NS2 and NS3? or I don´t need
> it?
> > perhaps I´m mixing concepts....
> >
> > Thanks again,
> >
> > Greetings,
> >
> > ESGLinux
> >
> >
> >
> >
> > 2012/12/20 Harsh J <[EMAIL PROTECTED]>
> >>
> >> Hi ESGLinux,
> >>
> >> Federation and HA are two distinct features that share some common
> >> properties but nothing more. You can turn on HA for any selected
> >> Namespace but it is not necessarily needed to be that all Namespaces
> >> have HA.
> >>
> >> Perhaps an example will clear it up for you.
> >>
> >> I have a local instance that is configured to run several namespaces:
> >> ns1, ns2, and ns3 (Federated Namespaces).
> >> The namespace ns1 hosts my HBase tables and is critical to me, so I
> >> have also turned on HA for this namespace alone.
> >> The other two namespaces ns2 and ns3 are used only for regular query
> >> jobs so its not yet very important for me to have HA on it. So I run
> >> them without HA.
> >>
> >> Thus I have 4 NameNode processes in my cluster in all, given my design
> >> above: (2 NNs under ns1, in HA mode) + (1 NN of ns2) + (1 NN of ns3).
> >>
> >> On Thu, Dec 20, 2012 at 10:00 PM, ESGLinux <[EMAIL PROTECTED]> wrote:
> >> > Hi All,
> >> >
> >> > I´m going to test a hadoop cluster and I have a doubt about HA and
> >> > Federation.
> >> >
> >> > With federation I Have a NameNode per namespace and with HA I have an
> >> > Active
> >> > NameNode and a standby NameNode.
> >> >
> >> > so, as I have sevaral namespaces, do I need an Active NameNode and a
> >> > standby
> >> > nameNode per namespace?
> >> >
> >> > I have read this documentation but It´s not clear for me :-(
> >> >
> >> >
> >> >
> https://ccp.cloudera.com/display/CDH4DOC/Introduction+to+Hadoop+High+Availability
> >> >
> >> >
> http://hadoop.apache.org/docs/r0.23.0/hadoop-yarn/hadoop-yarn-site/Federation.html
> >> >
> >> > Thanks in advance
> >> >
> >> > ESGLinux
> >> >
> >>
> >>
> >>
> >> --
> >> Harsh J
> >
> >
>
>
>
> --
> Harsh J
>
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Harsh J 2012-12-20, 17:57
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ESGLinux 2012-12-20, 18:03
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Harsh J 2012-12-20, 18:26