# Role of dedicated master nodes when not elected **URL:** \ **Category:** Elasticsearch\ **Created:** [August 11, 2014, 6:18pm UTC](https://discuss.elastic.co/t/role-of-dedicated-master-nodes-when-not-elected/19203 "2014-08-11T18:18:08Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![mhughes](https://avatars.discourse-cdn.com/v4/letter/m/85e7bf/32.png) [@mhughes](https://discuss.elastic.co/u/mhughes)\ **Post date:** [August 11, 2014, 6:18pm UTC](https://discuss.elastic.co/t/role-of-dedicated-master-nodes-when-not-elected/19203/1 "2014-08-11T18:18:08Z")
Lots of ES best practice articles recommend having dedicated master nodes. Specifically, that would involve setting these flags: node.master: true node.data: false Say, you had 7 index nodes and 3 master nodes ([https://blog.hipchat.com/2013/10/16/how-hipchat-scales-to-1-billion-messages/](https://blog.hipchat.com/2013/10/16/how-hipchat-scales-to-1-billion-messages/)) in your cluster. Only one of those three master-eligible nodes are going to be elected master; what do the other two do? Do they just exist for resiliency for when the elected master goes down? Do they literally not have any other role when not elected? -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/bdfb55a0-6645-4cac-b342-10956f87c87d%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/bdfb55a0-6645-4cac-b342-10956f87c87d%40googlegroups.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![mhughes](https://avatars.discourse-cdn.com/v4/letter/m/85e7bf/32.png) [@mhughes](https://discuss.elastic.co/u/mhughes)\ **Post date:** [August 11, 2014, 6:33pm UTC](https://discuss.elastic.co/t/role-of-dedicated-master-nodes-when-not-elected/19203/2 "2014-08-11T18:33:10Z")
As a followup, any ratio guidelines for indexing nodes vs dedicated masters. From what I can tell, it wouldn't make much sense to run with only one-dedicated master node; if that node goes down, your whole cluster becomes unavailable. On Monday, August 11, 2014 2:18:08 PM UTC-4, Matt Hughes wrote: > Lots of ES best practice articles recommend having dedicated master > nodes. Specifically, that would involve setting these flags: > > node.master: true > node.data: false > > Say, you had 7 index nodes and 3 master nodes ( > [https://blog.hipchat.com/2013/10/16/how-hipchat-scales-to-1-billion-messages/](https://blog.hipchat.com/2013/10/16/how-hipchat-scales-to-1-billion-messages/)) > in your cluster. Only one of those three master-eligible nodes are going > to be elected master; what do the other two do? Do they just exist for > resiliency for when the elected master goes down? Do they literally not > have any other role when not elected? -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/a3edb88a-8bfc-4cd6-bcb6-95cb29855921%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/a3edb88a-8bfc-4cd6-bcb6-95cb29855921%40googlegroups.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\ **Post date:** [August 11, 2014, 10:59pm UTC](https://discuss.elastic.co/t/role-of-dedicated-master-nodes-when-not-elected/19203/3 "2014-08-11T22:59:50Z")
They can act as search nodes, otherwise they don't do much. There are no guidelines other than using an odd number of masters, and as you pointed out, more than just 1. We currently have 3 masters for 25 data nodes. Regards, Mark Walkom Infrastructure Engineer Campaign Monitor email: [markw@campaignmonitor.com](mailto:markw@campaignmonitor.com) web: [www.campaignmonitor.com](http://www.campaignmonitor.com) On 12 August 2014 04:33, Matt Hughes [hughes.matt@gmail.com](mailto:hughes.matt@gmail.com) wrote: > As a followup, any ratio guidelines for indexing nodes vs dedicated > masters. From what I can tell, it wouldn't make much sense to run with > only one-dedicated master node; if that node goes down, your whole cluster > becomes unavailable. > > On Monday, August 11, 2014 2:18:08 PM UTC-4, Matt Hughes wrote: > > > Lots of ES best practice articles recommend having dedicated master > > nodes. Specifically, that would involve setting these flags: > > > > node.master: true > > node.data: false > > > > Say, you had 7 index nodes and 3 master nodes ([https://blog.hipchat.com/](https://blog.hipchat.com/) > > 2013/10/16/how-hipchat-scales-to-1-billion-messages/) in your cluster. > > Only one of those three master-eligible nodes are going to be elected > > master; what do the other two do? Do they just exist for resiliency for > > when the elected master goes down? Do they literally not have any other > > role when not elected? > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). > To view this discussion on the web visit > [https://groups.google.com/d/msgid/elasticsearch/a3edb88a-8bfc-4cd6-bcb6-95cb29855921%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/a3edb88a-8bfc-4cd6-bcb6-95cb29855921%40googlegroups.com) > [https://groups.google.com/d/msgid/elasticsearch/a3edb88a-8bfc-4cd6-bcb6-95cb29855921%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/a3edb88a-8bfc-4cd6-bcb6-95cb29855921%40googlegroups.com?utm_medium=email&utm_source=footer) > . > > For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/CAEM624ZWOAJwVuxTUj\_oqyPKfs2nuXJuwidNY0Zr79voAF8gZw%40mail.gmail.com](https://groups.google.com/d/msgid/elasticsearch/CAEM624ZWOAJwVuxTUj_oqyPKfs2nuXJuwidNY0Zr79voAF8gZw%40mail.gmail.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![jprante](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jprante/32/44941_2.png) [@jprante](https://discuss.elastic.co/u/jprante)\ **Post date:** [August 12, 2014, 7:00am UTC](https://discuss.elastic.co/t/role-of-dedicated-master-nodes-when-not-elected/19203/4 "2014-08-12T07:00:30Z")
The HTTP module is not disabled so the three master eligible nodes can also serve as result servers. Result servers can collect shard responses from other nodes for sending the merge result back to clients, without having to search or index. This is similar to a kind of a bridge or a proxy server. Jörg On Mon, Aug 11, 2014 at 8:18 PM, Matt Hughes [hughes.matt@gmail.com](mailto:hughes.matt@gmail.com) wrote: > Lots of ES best practice articles recommend having dedicated master > nodes. Specifically, that would involve setting these flags: > > node.master: true > node.data: false > > Say, you had 7 index nodes and 3 master nodes ( > [https://blog.hipchat.com/2013/10/16/how-hipchat-scales-to-1-billion-messages/](https://blog.hipchat.com/2013/10/16/how-hipchat-scales-to-1-billion-messages/)) > in your cluster. Only one of those three master-eligible nodes are going > to be elected master; what do the other two do? Do they just exist for > resiliency for when the elected master goes down? Do they literally not > have any other role when not elected? > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). > To view this discussion on the web visit > [https://groups.google.com/d/msgid/elasticsearch/bdfb55a0-6645-4cac-b342-10956f87c87d%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/bdfb55a0-6645-4cac-b342-10956f87c87d%40googlegroups.com) > [https://groups.google.com/d/msgid/elasticsearch/bdfb55a0-6645-4cac-b342-10956f87c87d%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/bdfb55a0-6645-4cac-b342-10956f87c87d%40googlegroups.com?utm_medium=email&utm_source=footer) > . > For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/CAKdsXoFzJ4XuJAd7NHZ2csD%2BYUadtC1yJnSn6tUJao%2BrHKQKnA%40mail.gmail.com](https://groups.google.com/d/msgid/elasticsearch/CAKdsXoFzJ4XuJAd7NHZ2csD%2BYUadtC1yJnSn6tUJao%2BrHKQKnA%40mail.gmail.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**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, 1:09am UTC](https://discuss.elastic.co/t/role-of-dedicated-master-nodes-when-not-elected/19203/5 "2017-07-06T01:09:22Z")