# Cluster nodes communication **URL:** \ **Category:** Elasticsearch\ **Created:** [May 28, 2010, 6:40am UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981 "2010-05-28T06:40:56Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![ray\_qi](https://avatars.discourse-cdn.com/v4/letter/r/edb3f5/32.png) [@ray\_qi](https://discuss.elastic.co/u/ray_qi)\ **Post date:** [May 28, 2010, 6:40am UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/1 "2010-05-28T06:40:56Z")
Hi There is only one single master in the cluster (automatically elected), since the master node maintains some critical information, I doubt if it will be the bottleneck when we have thousands of nodes. For master-node communication, is Zookeeper a better choice? Thanks ---
**Author:** ![Berkay\_Mollamustafao](https://avatars.discourse-cdn.com/v4/letter/b/22d042/32.png) [@Berkay\_Mollamustafao](https://discuss.elastic.co/u/Berkay_Mollamustafao)\ **Post date:** [May 28, 2010, 8:41pm UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/2 "2010-05-28T20:41:30Z")
Hi, Why do you say there is a master? AFAIK, all nodes are equal. Regards, Berkay Mollamustafaoglu mberkay on yahoo, google and skype On Fri, May 28, 2010 at 2:40 AM, ray.qi [ray7628@gmail.com](mailto:ray7628@gmail.com) wrote: > Hi > > There is only one single master in the cluster (automatically elected), > since the master node maintains some critical information, I doubt if it > will be the bottleneck when we have thousands of nodes. For master-node > communication, is Zookeeper a better choice? > > Thanks > > -- > View this message in context: > [http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p850919.html](http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p850919.html) > Sent from the Elasticsearch Users mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![Lukas\_Vlcek1](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/lukas_vlcek1/32/819_2.png) [@Lukas\_Vlcek1](https://discuss.elastic.co/u/Lukas_Vlcek1)\ **Post date:** [May 28, 2010, 9:06pm UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/3 "2010-05-28T21:06:50Z")
Hi, actually there is a master node. You can read what Shay explained about master node at sematext blog interview here (check comments section too): > **[Solr vs Elasticsearch: Performance Differences & More - Sematext](https://sematext.com/blog/solr-vs-elasticsearch-differences/)** > > How to decide between Solr vs Elasticsearch: Which one performs best, is faster, scales better & is easier to manage? Which one is best for you? Find out! It reads: A master in elasticsearch is responsible for handling nodes coming and going and allocation of shards. Note, the master is not a single point of failure, if it fails, then another node will be elected as master. Also note, that nodes do not need to communicate with the master on each request, so its not a single point of bottleneck. EOD As for the massive deployment (thousands of nodes) I do not have experience but I think there are other factors that can slow down performance significantly depending on cluster setup as sharding and replication needs to take place (though they can run on background the communication inside the cluster needs to happen between nodes and I think it would be much more data intensive communication compared to node-master communication). As for the cluster setup and other critical info AFAIK it should be persisted via gateway so if anything goes wrong and the cluster crashes there should be way how to recover. Regards, Lukas On Fri, May 28, 2010 at 10:41 PM, Berkay Mollamustafaoglu \<[mberkay@gmail.com](mailto:mberkay@gmail.com) > wrote: > Hi, > > Why do you say there is a master? AFAIK, all nodes are equal. > > Regards, > Berkay Mollamustafaoglu > mberkay on yahoo, google and skype > > On Fri, May 28, 2010 at 2:40 AM, ray.qi [ray7628@gmail.com](mailto:ray7628@gmail.com) wrote: > > > Hi > > > > There is only one single master in the cluster (automatically elected), > > since the master node maintains some critical information, I doubt if it > > will be the bottleneck when we have thousands of nodes. For master-node > > communication, is Zookeeper a better choice? > > > > Thanks > > > > -- > > View this message in context: > > [http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p850919.html](http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p850919.html) > > Sent from the Elasticsearch Users mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [May 28, 2010, 10:34pm UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/4 "2010-05-28T22:34:14Z")
Just another point regarding zookeeper, elasticsearch architecture is similar in its idea to a zookeeper based cluster management, with several exceptions: 1. The master is dynamically allocated, so no preferred number of master nodes. 2. Setup is sooo much simpler, and did someone said cloud :). Zookeeper is a pain to setup in cloud envs, elastic ips, special nodes, all are relics of "non cloudy" discovery models, which, by the way, plays much nicer also when not in the cloud. 3. Long term persistency (i.e. full cluster failure) of the cluster state is maintained through the gateway. 4. I would venture a guess (and its just a guess) that elasticsearch is more scalable than zookeeper (when it comes to cluster state management). Note, I am evaluating zookeeper here only for the subset of features elasticsearch would have needed from it. Zookeeper provides much more features that are irrelevant to elasticsearch which makes it cool to use in other scenarios. cheers, shay.banon On Sat, May 29, 2010 at 12:06 AM, Lukáš Vlček [lukas.vlcek@gmail.com](mailto:lukas.vlcek@gmail.com) wrote: > Hi, > > actually there is a master node. You can read what Shay explained about > master node at sematext blog interview here (check comments section too): > [Solr vs Elasticsearch: Performance Differences & More - Sematext](http://blog.sematext.com/2010/05/03/elastic-search-distributed-lucene/) > > It reads: > A master in elasticsearch is responsible for handling nodes coming and > going and allocation of shards. Note, the master is not a single point of > failure, if it fails, then another node will be elected as master. Also > note, that nodes do not need to communicate with the master on each request, > so its not a single point of bottleneck. > EOD > > As for the massive deployment (thousands of nodes) I do not have experience > but I think there are other factors that can slow down performance > significantly depending on cluster setup as sharding and replication needs > to take place (though they can run on background the communication inside > the cluster needs to happen between nodes and I think it would be much more > data intensive communication compared to node-master communication). As for > the cluster setup and other critical info AFAIK it should be persisted via > gateway so if anything goes wrong and the cluster crashes there should be > way how to recover. > > Regards, > Lukas > > On Fri, May 28, 2010 at 10:41 PM, Berkay Mollamustafaoglu \< > [mberkay@gmail.com](mailto:mberkay@gmail.com)\> wrote: > > > Hi, > > > > Why do you say there is a master? AFAIK, all nodes are equal. > > > > Regards, > > Berkay Mollamustafaoglu > > mberkay on yahoo, google and skype > > > > On Fri, May 28, 2010 at 2:40 AM, ray.qi [ray7628@gmail.com](mailto:ray7628@gmail.com) wrote: > > > > > Hi > > > > > > There is only one single master in the cluster (automatically elected), > > > since the master node maintains some critical information, I doubt if it > > > will be the bottleneck when we have thousands of nodes. For master-node > > > communication, is Zookeeper a better choice? > > > > > > Thanks > > > > > > -- > > > View this message in context: > > > [http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p850919.html](http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p850919.html) > > > Sent from the Elasticsearch Users mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![ray\_qi](https://avatars.discourse-cdn.com/v4/letter/r/edb3f5/32.png) [@ray\_qi](https://discuss.elastic.co/u/ray_qi)\ **Post date:** [May 29, 2010, 1:43am UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/5 "2010-05-29T01:43:41Z")
Thanks for prompt replying. AFAIK, The design of ElasticSearch is perfect after I compared serval solutions from code level. As for the massive deployment (thousands of nodes), I still have some concerns about performance regarding the communication of node-master, nodes-nodes and nodes-gateway. That's why I seek other potential options or make some changes to make it better. Probably you genius guys can give some predictions of performance bottleneck in massive deployment situation. Regards -Ray ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [June 1, 2010, 8:21pm UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/6 "2010-06-01T20:21:43Z")
Well, I have not tested yet thousands of nodes, but master node communication seems to work for hadoop ... On Sat, May 29, 2010 at 4:43 AM, ray.qi [ray7628@gmail.com](mailto:ray7628@gmail.com) wrote: > Thanks for prompt replying. > > AFAIK, The design of Elasticsearch is perfect after I compared serval > solutions from code level. As for the massive deployment (thousands of > nodes), I still have some concerns about performance regarding the > communication of node-master, nodes-nodes and nodes-gateway. That's why I > seek other potential options or make some changes to make it better. > Probably you genius guys can give some predictions of performance > bottleneck > in massive deployment situation. > > Regards > -Ray > > -- > View this message in context: > [http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p853589.html](http://elasticsearch-users.115913.n3.nabble.com/cluster-nodes-communication-tp850919p853589.html) > Sent from the Elasticsearch Users mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 4:23am UTC](https://discuss.elastic.co/t/cluster-nodes-communication/2981/7 "2017-07-06T04:23:40Z")