Hello,

Trying to follow directions from here:
http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServerSetup

to setup a cluster of zookeepers.

Questions:

1)  If everything is setup correctly, do I have to go to each machine and
start Zookeeper server in each of them individually?
2)  I was thinking if I start it on one master machine (well there's no
real master) then all zookeepers in the quorum would be started, but this
is not how it works correct?
3)  If I start individually, then I get messages saying the other
zookeepers haven't started.  Is that just a warning?
4)  When all of them are started, would they all be able to talk to each
other?

Sorry for the dumb questions and thanks for the help.

Yes, you must start them all individually. ZooKeeper does not currently
have any cluster-wide management tools built in.

FYI - we've open sourced a cluster management tool for ZooKeeper. Please
have a look:

https://github.com/Netflix/exhibitor

On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]> wrote:

>Hello,
>
>Trying to follow directions from here:
>http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServer
>Setup
>
>to setup a cluster of zookeepers.
>
>Questions:
>
>1)  If everything is setup correctly, do I have to go to each machine and
>start Zookeeper server in each of them individually?
>2)  I was thinking if I start it on one master machine (well there's no
>real master) then all zookeepers in the quorum would be started, but this
>is not how it works correct?
>3)  If I start individually, then I get messages saying the other
>zookeepers haven't started.  Is that just a warning?
>4)  When all of them are started, would they all be able to talk to each
>other?
>
>Sorry for the dumb questions and thanks for the help.

Thanks Jordan.  Will definitely look at the cluster management tool.  In
the mean time, am I correct with my assumption in #4?  Once all of them are
started they would automagically start talking to each other, right?
On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman <[EMAIL PROTECTED]>wrote:

> Yes, you must start them all individually. ZooKeeper does not currently
> have any cluster-wide management tools built in.
>
> FYI - we've open sourced a cluster management tool for ZooKeeper. Please
> have a look:
>
>        https://github.com/Netflix/exhibitor
>
> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]> wrote:
>
> >Hello,
> >
> >Trying to follow directions from here:
> >
> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServer
> >Setup
> >
> >to setup a cluster of zookeepers.
> >
> >Questions:
> >
> >1)  If everything is setup correctly, do I have to go to each machine and
> >start Zookeeper server in each of them individually?
> >2)  I was thinking if I start it on one master machine (well there's no
> >real master) then all zookeepers in the quorum would be started, but this
> >is not how it works correct?
> >3)  If I start individually, then I get messages saying the other
> >zookeepers haven't started.  Is that just a warning?
> >4)  When all of them are started, would they all be able to talk to each
> >other?
> >
> >Sorry for the dumb questions and thanks for the help.
>
>

Yes - they should. Keep in mind that the zoo.cfg, and the ID file must be
correct and in agreement on each instance. You can do a stat on each
instance to see what state it's in:

    >telnet localhost 2181
     stat

-JZ

On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]> wrote:

>Thanks Jordan.  Will definitely look at the cluster management tool.  In
>the mean time, am I correct with my assumption in #4?  Once all of them
>are
>started they would automagically start talking to each other, right?
>
>
>On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
><[EMAIL PROTECTED]>wrote:
>
>> Yes, you must start them all individually. ZooKeeper does not currently
>> have any cluster-wide management tools built in.
>>
>> FYI - we've open sourced a cluster management tool for ZooKeeper. Please
>> have a look:
>>
>>        https://github.com/Netflix/exhibitor
>>
>> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]>
>>wrote:
>>
>> >Hello,
>> >
>> >Trying to follow directions from here:
>> >
>>
>>http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
>>r
>> >Setup
>> >
>> >to setup a cluster of zookeepers.
>> >
>> >Questions:
>> >
>> >1)  If everything is setup correctly, do I have to go to each machine
>>and
>> >start Zookeeper server in each of them individually?
>> >2)  I was thinking if I start it on one master machine (well there's no
>> >real master) then all zookeepers in the quorum would be started, but
>>this
>> >is not how it works correct?
>> >3)  If I start individually, then I get messages saying the other
>> >zookeepers haven't started.  Is that just a warning?
>> >4)  When all of them are started, would they all be able to talk to
>>each
>> >other?
>> >
>> >Sorry for the dumb questions and thanks for the help.
>>
>>

Hmm...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
stat
Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
Clients:
 /127.0.0.1:42510[0](queued=0,recved=1,sent=0)

Latency min/avg/max: 0/0/0
Received: 4
Sent: 3
Outstanding: 0
Zxid: 0x100000000
Mode: follower
Node count: 11
Connection closed by foreign host.
Not sure I understand this output.  I have 9 nodes in the ensemble.

On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman <[EMAIL PROTECTED]>wrote:

> Yes - they should. Keep in mind that the zoo.cfg, and the ID file must be
> correct and in agreement on each instance. You can do a stat on each
> instance to see what state it's in:
>
>    >telnet localhost 2181
>     stat
>
> -JZ
>
> On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]> wrote:
>
> >Thanks Jordan.  Will definitely look at the cluster management tool.  In
> >the mean time, am I correct with my assumption in #4?  Once all of them
> >are
> >started they would automagically start talking to each other, right?
> >
> >
> >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
> ><[EMAIL PROTECTED]>wrote:
> >
> >> Yes, you must start them all individually. ZooKeeper does not currently
> >> have any cluster-wide management tools built in.
> >>
> >> FYI - we've open sourced a cluster management tool for ZooKeeper. Please
> >> have a look:
> >>
> >>        https://github.com/Netflix/exhibitor
> >>
> >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]>
> >>wrote:
> >>
> >> >Hello,
> >> >
> >> >Trying to follow directions from here:
> >> >
> >>
> >>
> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
> >>r
> >> >Setup
> >> >
> >> >to setup a cluster of zookeepers.
> >> >
> >> >Questions:
> >> >
> >> >1)  If everything is setup correctly, do I have to go to each machine
> >>and
> >> >start Zookeeper server in each of them individually?
> >> >2)  I was thinking if I start it on one master machine (well there's no
> >> >real master) then all zookeepers in the quorum would be started, but
> >>this
> >> >is not how it works correct?
> >> >3)  If I start individually, then I get messages saying the other
> >> >zookeepers haven't started.  Is that just a warning?
> >> >4)  When all of them are started, would they all be able to talk to
> >>each
> >> >other?
> >> >
> >> >Sorry for the dumb questions and thanks for the help.
> >>
> >>
>
>

You have 9 instances? That's a lot. Why so many?

I believe the "Node" field in the stat is the number of ZKNodes, not
instances in the ensemble. That stat looks good. It means that that
instance is serving requests as a "follower" instance (one of the
instances will be the leader).

-JZ

On 5/8/12 2:54 PM, "Something Something" <[EMAIL PROTECTED]> wrote:

>Hmm...
>
>
>Trying 127.0.0.1...
>Connected to localhost.
>Escape character is '^]'.
>stat
>Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
>Clients:
> /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
>
>Latency min/avg/max: 0/0/0
>Received: 4
>Sent: 3
>Outstanding: 0
>Zxid: 0x100000000
>Mode: follower
>Node count: 11
>Connection closed by foreign host.
>
>
>Not sure I understand this output.  I have 9 nodes in the ensemble.
>
>On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman
><[EMAIL PROTECTED]>wrote:
>
>> Yes - they should. Keep in mind that the zoo.cfg, and the ID file must
>>be
>> correct and in agreement on each instance. You can do a stat on each
>> instance to see what state it's in:
>>
>>    >telnet localhost 2181
>>     stat
>>
>> -JZ
>>
>> On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
>>wrote:
>>
>> >Thanks Jordan.  Will definitely look at the cluster management tool.
>>In
>> >the mean time, am I correct with my assumption in #4?  Once all of them
>> >are
>> >started they would automagically start talking to each other, right?
>> >
>> >
>> >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
>> ><[EMAIL PROTECTED]>wrote:
>> >
>> >> Yes, you must start them all individually. ZooKeeper does not
>>currently
>> >> have any cluster-wide management tools built in.
>> >>
>> >> FYI - we've open sourced a cluster management tool for ZooKeeper.
>>Please
>> >> have a look:
>> >>
>> >>        https://github.com/Netflix/exhibitor
>> >>
>> >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]>
>> >>wrote:
>> >>
>> >> >Hello,
>> >> >
>> >> >Trying to follow directions from here:
>> >> >
>> >>
>> >>
>>
>>http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
>> >>r
>> >> >Setup
>> >> >
>> >> >to setup a cluster of zookeepers.
>> >> >
>> >> >Questions:
>> >> >
>> >> >1)  If everything is setup correctly, do I have to go to each
>>machine
>> >>and
>> >> >start Zookeeper server in each of them individually?
>> >> >2)  I was thinking if I start it on one master machine (well
>>there's no
>> >> >real master) then all zookeepers in the quorum would be started, but
>> >>this
>> >> >is not how it works correct?
>> >> >3)  If I start individually, then I get messages saying the other
>> >> >zookeepers haven't started.  Is that just a warning?
>> >> >4)  When all of them are started, would they all be able to talk to
>> >>each
>> >> >other?
>> >> >
>> >> >Sorry for the dumb questions and thanks for the help.
>> >>
>> >>
>>
>>

We have a cluster of 17 machines.  Somewhere in the HBase documentation I
read - usually we should divide by 2 & use an odd number.  May be I
mis-read.  That's why I started Zookeeper on 9 machines.  I guess, I don't
understand the difference between Nodes & Instance.  I expected ZKNodes to
be 9.  Please explain.  Thanks a lot for your help.

On Tue, May 8, 2012 at 3:05 PM, Jordan Zimmerman <[EMAIL PROTECTED]>wrote:

> You have 9 instances? That's a lot. Why so many?
>
> I believe the "Node" field in the stat is the number of ZKNodes, not
> instances in the ensemble. That stat looks good. It means that that
> instance is serving requests as a "follower" instance (one of the
> instances will be the leader).
>
> -JZ
>
> On 5/8/12 2:54 PM, "Something Something" <[EMAIL PROTECTED]> wrote:
>
> >Hmm...
> >
> >
> >Trying 127.0.0.1...
> >Connected to localhost.
> >Escape character is '^]'.
> >stat
> >Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
> >Clients:
> > /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
> >
> >Latency min/avg/max: 0/0/0
> >Received: 4
> >Sent: 3
> >Outstanding: 0
> >Zxid: 0x100000000
> >Mode: follower
> >Node count: 11
> >Connection closed by foreign host.
> >
> >
> >Not sure I understand this output.  I have 9 nodes in the ensemble.
> >
> >On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman
> ><[EMAIL PROTECTED]>wrote:
> >
> >> Yes - they should. Keep in mind that the zoo.cfg, and the ID file must
> >>be
> >> correct and in agreement on each instance. You can do a stat on each
> >> instance to see what state it's in:
> >>
> >>    >telnet localhost 2181
> >>     stat
> >>
> >> -JZ
> >>
> >> On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
> >>wrote:
> >>
> >> >Thanks Jordan.  Will definitely look at the cluster management tool.
> >>In
> >> >the mean time, am I correct with my assumption in #4?  Once all of them
> >> >are
> >> >started they would automagically start talking to each other, right?
> >> >
> >> >
> >> >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
> >> ><[EMAIL PROTECTED]>wrote:
> >> >
> >> >> Yes, you must start them all individually. ZooKeeper does not
> >>currently
> >> >> have any cluster-wide management tools built in.
> >> >>
> >> >> FYI - we've open sourced a cluster management tool for ZooKeeper.
> >>Please
> >> >> have a look:
> >> >>
> >> >>        https://github.com/Netflix/exhibitor
> >> >>
> >> >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]>
> >> >>wrote:
> >> >>
> >> >> >Hello,
> >> >> >
> >> >> >Trying to follow directions from here:
> >> >> >
> >> >>
> >> >>
> >>
> >>
> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
> >> >>r
> >> >> >Setup
> >> >> >
> >> >> >to setup a cluster of zookeepers.
> >> >> >
> >> >> >Questions:
> >> >> >
> >> >> >1)  If everything is setup correctly, do I have to go to each
> >>machine
> >> >>and
> >> >> >start Zookeeper server in each of them individually?
> >> >> >2)  I was thinking if I start it on one master machine (well
> >>there's no
> >> >> >real master) then all zookeepers in the quorum would be started, but
> >> >>this
> >> >> >is not how it works correct?
> >> >> >3)  If I start individually, then I get messages saying the other
> >> >> >zookeepers haven't started.  Is that just a warning?
> >> >> >4)  When all of them are started, would they all be able to talk to
> >> >>each
> >> >> >other?
> >> >> >
> >> >> >Sorry for the dumb questions and thanks for the help.
> >> >>
> >> >>
> >>
> >>
>
>

For most uses, 3 instances is enough. For heavy usage, 5 instances can be
used. ZooKeeper write performance degrades with the number of instances
added. There's a lot of doc on the net about this.

A ZNode is a data entry in the ZooKeeper database. An instance is a server
running the ZooKeeper software.

-JZ

On 5/8/12 3:13 PM, "Something Something" <[EMAIL PROTECTED]> wrote:

>We have a cluster of 17 machines.  Somewhere in the HBase documentation I
>read - usually we should divide by 2 & use an odd number.  May be I
>mis-read.  That's why I started Zookeeper on 9 machines.  I guess, I don't
>understand the difference between Nodes & Instance.  I expected ZKNodes to
>be 9.  Please explain.  Thanks a lot for your help.
>
>On Tue, May 8, 2012 at 3:05 PM, Jordan Zimmerman
><[EMAIL PROTECTED]>wrote:
>
>> You have 9 instances? That's a lot. Why so many?
>>
>> I believe the "Node" field in the stat is the number of ZKNodes, not
>> instances in the ensemble. That stat looks good. It means that that
>> instance is serving requests as a "follower" instance (one of the
>> instances will be the leader).
>>
>> -JZ
>>
>> On 5/8/12 2:54 PM, "Something Something" <[EMAIL PROTECTED]>
>>wrote:
>>
>> >Hmm...
>> >
>> >
>> >Trying 127.0.0.1...
>> >Connected to localhost.
>> >Escape character is '^]'.
>> >stat
>> >Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
>> >Clients:
>> > /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
>> >
>> >Latency min/avg/max: 0/0/0
>> >Received: 4
>> >Sent: 3
>> >Outstanding: 0
>> >Zxid: 0x100000000
>> >Mode: follower
>> >Node count: 11
>> >Connection closed by foreign host.
>> >
>> >
>> >Not sure I understand this output.  I have 9 nodes in the ensemble.
>> >
>> >On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman
>> ><[EMAIL PROTECTED]>wrote:
>> >
>> >> Yes - they should. Keep in mind that the zoo.cfg, and the ID file
>>must
>> >>be
>> >> correct and in agreement on each instance. You can do a stat on each
>> >> instance to see what state it's in:
>> >>
>> >>    >telnet localhost 2181
>> >>     stat
>> >>
>> >> -JZ
>> >>
>> >> On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
>> >>wrote:
>> >>
>> >> >Thanks Jordan.  Will definitely look at the cluster management tool.
>> >>In
>> >> >the mean time, am I correct with my assumption in #4?  Once all of
>>them
>> >> >are
>> >> >started they would automagically start talking to each other, right?
>> >> >
>> >> >
>> >> >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
>> >> ><[EMAIL PROTECTED]>wrote:
>> >> >
>> >> >> Yes, you must start them all individually. ZooKeeper does not
>> >>currently
>> >> >> have any cluster-wide management tools built in.
>> >> >>
>> >> >> FYI - we've open sourced a cluster management tool for ZooKeeper.
>> >>Please
>> >> >> have a look:
>> >> >>
>> >> >>        https://github.com/Netflix/exhibitor
>> >> >>
>> >> >> On 5/8/12 2:31 PM, "Something Something"
>><[EMAIL PROTECTED]>
>> >> >>wrote:
>> >> >>
>> >> >> >Hello,
>> >> >> >
>> >> >> >Trying to follow directions from here:
>> >> >> >
>> >> >>
>> >> >>
>> >>
>> >>
>>
>>http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
>> >> >>r
>> >> >> >Setup
>> >> >> >
>> >> >> >to setup a cluster of zookeepers.
>> >> >> >
>> >> >> >Questions:
>> >> >> >
>> >> >> >1)  If everything is setup correctly, do I have to go to each
>> >>machine
>> >> >>and
>> >> >> >start Zookeeper server in each of them individually?
>> >> >> >2)  I was thinking if I start it on one master machine (well
>> >>there's no
>> >> >> >real master) then all zookeepers in the quorum would be started,
>>but
>> >> >>this
>> >> >> >is not how it works correct?
>> >> >> >3)  If I start individually, then I get messages saying the other
>> >> >> >zookeepers haven't started.  Is that just a warning?
>> >> >> >4)  When all of them are started, would they all be able to talk
>>to
>> >> >>each
>> >> >> >other?
>> >> >> >
>> >> >> >Sorry for the dumb questions and thanks for the help.

Thanks.  Took your advice & cut down the number to 5 instances.  Confirmed
that one of them is a leader & the rest are followers.  Now on to
installing HBase.  Thanks again.

On Tue, May 8, 2012 at 3:19 PM, Jordan Zimmerman <[EMAIL PROTECTED]>wrote:

> For most uses, 3 instances is enough. For heavy usage, 5 instances can be
> used. ZooKeeper write performance degrades with the number of instances
> added. There's a lot of doc on the net about this.
>
> A ZNode is a data entry in the ZooKeeper database. An instance is a server
> running the ZooKeeper software.
>
> -JZ
>
> On 5/8/12 3:13 PM, "Something Something" <[EMAIL PROTECTED]> wrote:
>
> >We have a cluster of 17 machines.  Somewhere in the HBase documentation I
> >read - usually we should divide by 2 & use an odd number.  May be I
> >mis-read.  That's why I started Zookeeper on 9 machines.  I guess, I don't
> >understand the difference between Nodes & Instance.  I expected ZKNodes to
> >be 9.  Please explain.  Thanks a lot for your help.
> >
> >On Tue, May 8, 2012 at 3:05 PM, Jordan Zimmerman
> ><[EMAIL PROTECTED]>wrote:
> >
> >> You have 9 instances? That's a lot. Why so many?
> >>
> >> I believe the "Node" field in the stat is the number of ZKNodes, not
> >> instances in the ensemble. That stat looks good. It means that that
> >> instance is serving requests as a "follower" instance (one of the
> >> instances will be the leader).
> >>
> >> -JZ
> >>
> >> On 5/8/12 2:54 PM, "Something Something" <[EMAIL PROTECTED]>
> >>wrote:
> >>
> >> >Hmm...
> >> >
> >> >
> >> >Trying 127.0.0.1...
> >> >Connected to localhost.
> >> >Escape character is '^]'.
> >> >stat
> >> >Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
> >> >Clients:
> >> > /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
> >> >
> >> >Latency min/avg/max: 0/0/0
> >> >Received: 4
> >> >Sent: 3
> >> >Outstanding: 0
> >> >Zxid: 0x100000000
> >> >Mode: follower
> >> >Node count: 11
> >> >Connection closed by foreign host.
> >> >
> >> >
> >> >Not sure I understand this output.  I have 9 nodes in the ensemble.
> >> >
> >> >On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman
> >> ><[EMAIL PROTECTED]>wrote:
> >> >
> >> >> Yes - they should. Keep in mind that the zoo.cfg, and the ID file
> >>must
> >> >>be
> >> >> correct and in agreement on each instance. You can do a stat on each
> >> >> instance to see what state it's in:
> >> >>
> >> >>    >telnet localhost 2181
> >> >>     stat
> >> >>
> >> >> -JZ
> >> >>
> >> >> On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
> >> >>wrote:
> >> >>
> >> >> >Thanks Jordan.  Will definitely look at the cluster management tool.
> >> >>In
> >> >> >the mean time, am I correct with my assumption in #4?  Once all of
> >>them
> >> >> >are
> >> >> >started they would automagically start talking to each other, right?
> >> >> >
> >> >> >
> >> >> >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
> >> >> ><[EMAIL PROTECTED]>wrote:
> >> >> >
> >> >> >> Yes, you must start them all individually. ZooKeeper does not
> >> >>currently
> >> >> >> have any cluster-wide management tools built in.
> >> >> >>
> >> >> >> FYI - we've open sourced a cluster management tool for ZooKeeper.
> >> >>Please
> >> >> >> have a look:
> >> >> >>
> >> >> >>        https://github.com/Netflix/exhibitor
> >> >> >>
> >> >> >> On 5/8/12 2:31 PM, "Something Something"
> >><[EMAIL PROTECTED]>
> >> >> >>wrote:
> >> >> >>
> >> >> >> >Hello,
> >> >> >> >
> >> >> >> >Trying to follow directions from here:
> >> >> >> >
> >> >> >>
> >> >> >>
> >> >>
> >> >>
> >>
> >>
> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
> >> >> >>r
> >> >> >> >Setup
> >> >> >> >
> >> >> >> >to setup a cluster of zookeepers.
> >> >> >> >
> >> >> >> >Questions:
> >> >> >> >
> >> >> >> >1)  If everything is setup correctly, do I have to go to each
> >> >>machine
> >> >> >>and
> >> >> >> >start Zookeeper server in each of them individually?
> >> >> >> >2)  I was thinking if I start it on one master machine (well

I have often gotten confused by the "Node Count" field from stat, thinking
it meant cluster nodes, not znodes. I have to remind myself every time I
see it. Folks amenable to changing the name?

.. Adam

On Tue, May 8, 2012 at 2:54 PM, Something Something <
[EMAIL PROTECTED]> wrote:

> Hmm...
>
>
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^]'.
> stat
> Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
> Clients:
>  /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
>
> Latency min/avg/max: 0/0/0
> Received: 4
> Sent: 3
> Outstanding: 0
> Zxid: 0x100000000
> Mode: follower
> Node count: 11
> Connection closed by foreign host.
>
>
> Not sure I understand this output.  I have 9 nodes in the ensemble.
>
> On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman <[EMAIL PROTECTED]
> >wrote:
>
> > Yes - they should. Keep in mind that the zoo.cfg, and the ID file must be
> > correct and in agreement on each instance. You can do a stat on each
> > instance to see what state it's in:
> >
> >    >telnet localhost 2181
> >     stat
> >
> > -JZ
> >
> > On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
> wrote:
> >
> > >Thanks Jordan.  Will definitely look at the cluster management tool.  In
> > >the mean time, am I correct with my assumption in #4?  Once all of them
> > >are
> > >started they would automagically start talking to each other, right?
> > >
> > >
> > >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
> > ><[EMAIL PROTECTED]>wrote:
> > >
> > >> Yes, you must start them all individually. ZooKeeper does not
> currently
> > >> have any cluster-wide management tools built in.
> > >>
> > >> FYI - we've open sourced a cluster management tool for ZooKeeper.
> Please
> > >> have a look:
> > >>
> > >>        https://github.com/Netflix/exhibitor
> > >>
> > >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]>
> > >>wrote:
> > >>
> > >> >Hello,
> > >> >
> > >> >Trying to follow directions from here:
> > >> >
> > >>
> > >>
> >
> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
> > >>r
> > >> >Setup
> > >> >
> > >> >to setup a cluster of zookeepers.
> > >> >
> > >> >Questions:
> > >> >
> > >> >1)  If everything is setup correctly, do I have to go to each machine
> > >>and
> > >> >start Zookeeper server in each of them individually?
> > >> >2)  I was thinking if I start it on one master machine (well there's
> no
> > >> >real master) then all zookeepers in the quorum would be started, but
> > >>this
> > >> >is not how it works correct?
> > >> >3)  If I start individually, then I get messages saying the other
> > >> >zookeepers haven't started.  Is that just a warning?
> > >> >4)  When all of them are started, would they all be able to talk to
> > >>each
> > >> >other?
> > >> >
> > >> >Sorry for the dumb questions and thanks for the help.
> > >>
> > >>
> >
> >
>

On Tue, May 8, 2012 at 3:46 PM, Something Something
<[EMAIL PROTECTED]> wrote:
> Thanks.  Took your advice & cut down the number to 5 instances.  Confirmed
> that one of them is a leader & the rest are followers.  Now on to
> installing HBase.  Thanks again.

FWIW I typically recommend 3 or 5. 3 is fine, but 5 allows you to do
maintenance (take a server out of production) and still be able to
handle an unexpected failure w/o the service going down.

Patrick

> On Tue, May 8, 2012 at 3:19 PM, Jordan Zimmerman <[EMAIL PROTECTED]>wrote:
>
>> For most uses, 3 instances is enough. For heavy usage, 5 instances can be
>> used. ZooKeeper write performance degrades with the number of instances
>> added. There's a lot of doc on the net about this.
>>
>> A ZNode is a data entry in the ZooKeeper database. An instance is a server
>> running the ZooKeeper software.
>>
>> -JZ
>>
>> On 5/8/12 3:13 PM, "Something Something" <[EMAIL PROTECTED]> wrote:
>>
>> >We have a cluster of 17 machines.  Somewhere in the HBase documentation I
>> >read - usually we should divide by 2 & use an odd number.  May be I
>> >mis-read.  That's why I started Zookeeper on 9 machines.  I guess, I don't
>> >understand the difference between Nodes & Instance.  I expected ZKNodes to
>> >be 9.  Please explain.  Thanks a lot for your help.
>> >
>> >On Tue, May 8, 2012 at 3:05 PM, Jordan Zimmerman
>> ><[EMAIL PROTECTED]>wrote:
>> >
>> >> You have 9 instances? That's a lot. Why so many?
>> >>
>> >> I believe the "Node" field in the stat is the number of ZKNodes, not
>> >> instances in the ensemble. That stat looks good. It means that that
>> >> instance is serving requests as a "follower" instance (one of the
>> >> instances will be the leader).
>> >>
>> >> -JZ
>> >>
>> >> On 5/8/12 2:54 PM, "Something Something" <[EMAIL PROTECTED]>
>> >>wrote:
>> >>
>> >> >Hmm...
>> >> >
>> >> >
>> >> >Trying 127.0.0.1...
>> >> >Connected to localhost.
>> >> >Escape character is '^]'.
>> >> >stat
>> >> >Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
>> >> >Clients:
>> >> > /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
>> >> >
>> >> >Latency min/avg/max: 0/0/0
>> >> >Received: 4
>> >> >Sent: 3
>> >> >Outstanding: 0
>> >> >Zxid: 0x100000000
>> >> >Mode: follower
>> >> >Node count: 11
>> >> >Connection closed by foreign host.
>> >> >
>> >> >
>> >> >Not sure I understand this output.  I have 9 nodes in the ensemble.
>> >> >
>> >> >On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman
>> >> ><[EMAIL PROTECTED]>wrote:
>> >> >
>> >> >> Yes - they should. Keep in mind that the zoo.cfg, and the ID file
>> >>must
>> >> >>be
>> >> >> correct and in agreement on each instance. You can do a stat on each
>> >> >> instance to see what state it's in:
>> >> >>
>> >> >>    >telnet localhost 2181
>> >> >>     stat
>> >> >>
>> >> >> -JZ
>> >> >>
>> >> >> On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
>> >> >>wrote:
>> >> >>
>> >> >> >Thanks Jordan.  Will definitely look at the cluster management tool.
>> >> >>In
>> >> >> >the mean time, am I correct with my assumption in #4?  Once all of
>> >>them
>> >> >> >are
>> >> >> >started they would automagically start talking to each other, right?
>> >> >> >
>> >> >> >
>> >> >> >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
>> >> >> ><[EMAIL PROTECTED]>wrote:
>> >> >> >
>> >> >> >> Yes, you must start them all individually. ZooKeeper does not
>> >> >>currently
>> >> >> >> have any cluster-wide management tools built in.
>> >> >> >>
>> >> >> >> FYI - we've open sourced a cluster management tool for ZooKeeper.
>> >> >>Please
>> >> >> >> have a look:
>> >> >> >>
>> >> >> >>        https://github.com/Netflix/exhibitor
>> >> >> >>
>> >> >> >> On 5/8/12 2:31 PM, "Something Something"
>> >><[EMAIL PROTECTED]>
>> >> >> >>wrote:
>> >> >> >>
>> >> >> >> >Hello,
>> >> >> >> >
>> >> >> >> >Trying to follow directions from here:
>> >> >> >> >
>> >> >> >>
>> >> >> >>
>> >> >>
>> >> >>
>> >>
>> >>
>

On Wed, May 9, 2012 at 8:33 AM, Adam Rosien <[EMAIL PROTECTED]> wrote:
> I have often gotten confused by the "Node Count" field from stat, thinking
> it meant cluster nodes, not znodes. I have to remind myself every time I
> see it. Folks amenable to changing the name?

The names are overloaded which is unfortunate, node vs znode vs server
node vs server instance.... Unfortunately it would be hard to change
at this point given many third party tools depend on the name. Perhaps
4.0?

Patrick

> On Tue, May 8, 2012 at 2:54 PM, Something Something <
> [EMAIL PROTECTED]> wrote:
>
>> Hmm...
>>
>>
>> Trying 127.0.0.1...
>> Connected to localhost.
>> Escape character is '^]'.
>> stat
>> Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
>> Clients:
>>  /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
>>
>> Latency min/avg/max: 0/0/0
>> Received: 4
>> Sent: 3
>> Outstanding: 0
>> Zxid: 0x100000000
>> Mode: follower
>> Node count: 11
>> Connection closed by foreign host.
>>
>>
>> Not sure I understand this output.  I have 9 nodes in the ensemble.
>>
>> On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman <[EMAIL PROTECTED]
>> >wrote:
>>
>> > Yes - they should. Keep in mind that the zoo.cfg, and the ID file must be
>> > correct and in agreement on each instance. You can do a stat on each
>> > instance to see what state it's in:
>> >
>> >    >telnet localhost 2181
>> >     stat
>> >
>> > -JZ
>> >
>> > On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
>> wrote:
>> >
>> > >Thanks Jordan.  Will definitely look at the cluster management tool.  In
>> > >the mean time, am I correct with my assumption in #4?  Once all of them
>> > >are
>> > >started they would automagically start talking to each other, right?
>> > >
>> > >
>> > >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
>> > ><[EMAIL PROTECTED]>wrote:
>> > >
>> > >> Yes, you must start them all individually. ZooKeeper does not
>> currently
>> > >> have any cluster-wide management tools built in.
>> > >>
>> > >> FYI - we've open sourced a cluster management tool for ZooKeeper.
>> Please
>> > >> have a look:
>> > >>
>> > >>        https://github.com/Netflix/exhibitor
>> > >>
>> > >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]>
>> > >>wrote:
>> > >>
>> > >> >Hello,
>> > >> >
>> > >> >Trying to follow directions from here:
>> > >> >
>> > >>
>> > >>
>> >
>> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
>> > >>r
>> > >> >Setup
>> > >> >
>> > >> >to setup a cluster of zookeepers.
>> > >> >
>> > >> >Questions:
>> > >> >
>> > >> >1)  If everything is setup correctly, do I have to go to each machine
>> > >>and
>> > >> >start Zookeeper server in each of them individually?
>> > >> >2)  I was thinking if I start it on one master machine (well there's
>> no
>> > >> >real master) then all zookeepers in the quorum would be started, but
>> > >>this
>> > >> >is not how it works correct?
>> > >> >3)  If I start individually, then I get messages saying the other
>> > >> >zookeepers haven't started.  Is that just a warning?
>> > >> >4)  When all of them are started, would they all be able to talk to
>> > >>each
>> > >> >other?
>> > >> >
>> > >> >Sorry for the dumb questions and thanks for the help.
>> > >>
>> > >>
>> >
>> >
>>

Should I file a JIRA?

On Wed, May 9, 2012 at 3:24 PM, Patrick Hunt <[EMAIL PROTECTED]> wrote:

> On Wed, May 9, 2012 at 8:33 AM, Adam Rosien <[EMAIL PROTECTED]> wrote:
> > I have often gotten confused by the "Node Count" field from stat,
> thinking
> > it meant cluster nodes, not znodes. I have to remind myself every time I
> > see it. Folks amenable to changing the name?
>
> The names are overloaded which is unfortunate, node vs znode vs server
> node vs server instance.... Unfortunately it would be hard to change
> at this point given many third party tools depend on the name. Perhaps
> 4.0?
>
> Patrick
>
> > On Tue, May 8, 2012 at 2:54 PM, Something Something <
> > [EMAIL PROTECTED]> wrote:
> >
> >> Hmm...
> >>
> >>
> >> Trying 127.0.0.1...
> >> Connected to localhost.
> >> Escape character is '^]'.
> >> stat
> >> Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
> >> Clients:
> >>  /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
> >>
> >> Latency min/avg/max: 0/0/0
> >> Received: 4
> >> Sent: 3
> >> Outstanding: 0
> >> Zxid: 0x100000000
> >> Mode: follower
> >> Node count: 11
> >> Connection closed by foreign host.
> >>
> >>
> >> Not sure I understand this output.  I have 9 nodes in the ensemble.
> >>
> >> On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman <
> [EMAIL PROTECTED]
> >> >wrote:
> >>
> >> > Yes - they should. Keep in mind that the zoo.cfg, and the ID file
> must be
> >> > correct and in agreement on each instance. You can do a stat on each
> >> > instance to see what state it's in:
> >> >
> >> >    >telnet localhost 2181
> >> >     stat
> >> >
> >> > -JZ
> >> >
> >> > On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
> >> wrote:
> >> >
> >> > >Thanks Jordan.  Will definitely look at the cluster management tool.
>  In
> >> > >the mean time, am I correct with my assumption in #4?  Once all of
> them
> >> > >are
> >> > >started they would automagically start talking to each other, right?
> >> > >
> >> > >
> >> > >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
> >> > ><[EMAIL PROTECTED]>wrote:
> >> > >
> >> > >> Yes, you must start them all individually. ZooKeeper does not
> >> currently
> >> > >> have any cluster-wide management tools built in.
> >> > >>
> >> > >> FYI - we've open sourced a cluster management tool for ZooKeeper.
> >> Please
> >> > >> have a look:
> >> > >>
> >> > >>        https://github.com/Netflix/exhibitor
> >> > >>
> >> > >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]
> >
> >> > >>wrote:
> >> > >>
> >> > >> >Hello,
> >> > >> >
> >> > >> >Trying to follow directions from here:
> >> > >> >
> >> > >>
> >> > >>
> >> >
> >>
> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
> >> > >>r
> >> > >> >Setup
> >> > >> >
> >> > >> >to setup a cluster of zookeepers.
> >> > >> >
> >> > >> >Questions:
> >> > >> >
> >> > >> >1)  If everything is setup correctly, do I have to go to each
> machine
> >> > >>and
> >> > >> >start Zookeeper server in each of them individually?
> >> > >> >2)  I was thinking if I start it on one master machine (well
> there's
> >> no
> >> > >> >real master) then all zookeepers in the quorum would be started,
> but
> >> > >>this
> >> > >> >is not how it works correct?
> >> > >> >3)  If I start individually, then I get messages saying the other
> >> > >> >zookeepers haven't started.  Is that just a warning?
> >> > >> >4)  When all of them are started, would they all be able to talk
> to
> >> > >>each
> >> > >> >other?
> >> > >> >
> >> > >> >Sorry for the dumb questions and thanks for the help.
> >> > >>
> >> > >>
> >> >
> >> >
> >>
>

On Thu, May 10, 2012 at 8:16 AM, Adam Rosien <[EMAIL PROTECTED]> wrote:
> Should I file a JIRA?

Yes.

Patrick

> On Wed, May 9, 2012 at 3:24 PM, Patrick Hunt <[EMAIL PROTECTED]> wrote:
>
>> On Wed, May 9, 2012 at 8:33 AM, Adam Rosien <[EMAIL PROTECTED]> wrote:
>> > I have often gotten confused by the "Node Count" field from stat,
>> thinking
>> > it meant cluster nodes, not znodes. I have to remind myself every time I
>> > see it. Folks amenable to changing the name?
>>
>> The names are overloaded which is unfortunate, node vs znode vs server
>> node vs server instance.... Unfortunately it would be hard to change
>> at this point given many third party tools depend on the name. Perhaps
>> 4.0?
>>
>> Patrick
>>
>> > On Tue, May 8, 2012 at 2:54 PM, Something Something <
>> > [EMAIL PROTECTED]> wrote:
>> >
>> >> Hmm...
>> >>
>> >>
>> >> Trying 127.0.0.1...
>> >> Connected to localhost.
>> >> Escape character is '^]'.
>> >> stat
>> >> Zookeeper version: 3.3.4-cdh3u3--1, built on 01/26/2012 20:09 GMT
>> >> Clients:
>> >>  /127.0.0.1:42510[0](queued=0,recved=1,sent=0)
>> >>
>> >> Latency min/avg/max: 0/0/0
>> >> Received: 4
>> >> Sent: 3
>> >> Outstanding: 0
>> >> Zxid: 0x100000000
>> >> Mode: follower
>> >> Node count: 11
>> >> Connection closed by foreign host.
>> >>
>> >>
>> >> Not sure I understand this output.  I have 9 nodes in the ensemble.
>> >>
>> >> On Tue, May 8, 2012 at 2:45 PM, Jordan Zimmerman <
>> [EMAIL PROTECTED]
>> >> >wrote:
>> >>
>> >> > Yes - they should. Keep in mind that the zoo.cfg, and the ID file
>> must be
>> >> > correct and in agreement on each instance. You can do a stat on each
>> >> > instance to see what state it's in:
>> >> >
>> >> >    >telnet localhost 2181
>> >> >     stat
>> >> >
>> >> > -JZ
>> >> >
>> >> > On 5/8/12 2:43 PM, "Something Something" <[EMAIL PROTECTED]>
>> >> wrote:
>> >> >
>> >> > >Thanks Jordan.  Will definitely look at the cluster management tool.
>>  In
>> >> > >the mean time, am I correct with my assumption in #4?  Once all of
>> them
>> >> > >are
>> >> > >started they would automagically start talking to each other, right?
>> >> > >
>> >> > >
>> >> > >On Tue, May 8, 2012 at 2:36 PM, Jordan Zimmerman
>> >> > ><[EMAIL PROTECTED]>wrote:
>> >> > >
>> >> > >> Yes, you must start them all individually. ZooKeeper does not
>> >> currently
>> >> > >> have any cluster-wide management tools built in.
>> >> > >>
>> >> > >> FYI - we've open sourced a cluster management tool for ZooKeeper.
>> >> Please
>> >> > >> have a look:
>> >> > >>
>> >> > >>        https://github.com/Netflix/exhibitor
>> >> > >>
>> >> > >> On 5/8/12 2:31 PM, "Something Something" <[EMAIL PROTECTED]
>> >
>> >> > >>wrote:
>> >> > >>
>> >> > >> >Hello,
>> >> > >> >
>> >> > >> >Trying to follow directions from here:
>> >> > >> >
>> >> > >>
>> >> > >>
>> >> >
>> >>
>> http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServe
>> >> > >>r
>> >> > >> >Setup
>> >> > >> >
>> >> > >> >to setup a cluster of zookeepers.
>> >> > >> >
>> >> > >> >Questions:
>> >> > >> >
>> >> > >> >1)  If everything is setup correctly, do I have to go to each
>> machine
>> >> > >>and
>> >> > >> >start Zookeeper server in each of them individually?
>> >> > >> >2)  I was thinking if I start it on one master machine (well
>> there's
>> >> no
>> >> > >> >real master) then all zookeepers in the quorum would be started,
>> but
>> >> > >>this
>> >> > >> >is not how it works correct?
>> >> > >> >3)  If I start individually, then I get messages saying the other
>> >> > >> >zookeepers haven't started.  Is that just a warning?
>> >> > >> >4)  When all of them are started, would they all be able to talk
>> to
>> >> > >>each
>> >> > >> >other?
>> >> > >> >
>> >> > >> >Sorry for the dumb questions and thanks for the help.
>> >> > >>
>> >> > >>
>> >> >
>> >> >
>> >>
>>