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 > >> >>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. > >> >> >> > >> >> >> > >> >> > >> >> > >> > >> > >
