# How Do I Add a Second Node?

**URL:** <https://discuss.elastic.co/t/how-do-i-add-a-second-node/62102>\
**Category:** Elasticsearch\
**Created:** [October 3, 2016, 7:18pm UTC](https://discuss.elastic.co/t/how-do-i-add-a-second-node/62102 "2016-10-03T19:18:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![krmathieu](https://avatars.discourse-cdn.com/v4/letter/k/b5e925/32.png) [@krmathieu](https://discuss.elastic.co/u/krmathieu)\
**Post date:** [October 3, 2016, 7:18pm UTC](https://discuss.elastic.co/t/how-do-i-add-a-second-node/62102/1 "2016-10-03T19:18:49Z")

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I installed Elasticsearch on Centos 6.7 using Yum and started pumping documents in (about 450K worth) and now see that my \_cluster health is showing yellow. I want to add another node but want to make sure that I understand the procedure correctly. Do I have to install another instance of Elasticsearch and configure it so that it uses the same cluster name as the first one? That is, I will actually have two running instances (nodes) of Elasticsearch? If so, what if any changes do I need to make to the configuration of the first node? Thanks.

Kevin

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**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [October 3, 2016, 7:39pm UTC](https://discuss.elastic.co/t/how-do-i-add-a-second-node/62102/2 "2016-10-03T19:39:58Z")

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> I installed Elasticsearch on Centos 6.7 using Yum and started pumping documents in (about 450K worth) and now see that my \_cluster health is showing yellow.

That's expected with a single node cluster where at least one index is configured to have one or more replicas (which probably is the default in your case).

> I want to add another node but want to make sure that I understand the procedure correctly. Do I have to install another instance of Elasticsearch and configure it so that it uses the same cluster name as the first one?

Yes, the cluster name must match.

> That is, I will actually have two running instances (nodes) of Elasticsearch?

Yes.

> If so, what if any changes do I need to make to the configuration of the first node? Thanks.

You should set the discovery.zen.ping.unicast.hosts option on each node so that it can locate the other node. With a two-node cluster you should also set the discovery.zen.minimum\_master\_nodes option to 2 to avoid split brain situations. Note that to get a cluster that survives even with one node down you need three nodes, not two.

> **[Node discovery | Elasticsearch Guide \[8.11\] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery-hosts-providers.html)**

Depending on what your current configuration is you may also need to adjust the network.host setting so that Elasticsearch binds to non-loopback interfaces.

> **[Networking | Elasticsearch Guide \[8.11\] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html)**

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**Author:** ![krmathieu](https://avatars.discourse-cdn.com/v4/letter/k/b5e925/32.png) [@krmathieu](https://discuss.elastic.co/u/krmathieu)\
**Post date:** [October 3, 2016, 7:54pm UTC](https://discuss.elastic.co/t/how-do-i-add-a-second-node/62102/3 "2016-10-03T19:54:14Z")

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@magnusbaeck Thank you very much for the detailed explanation and quick response!

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 10:15pm UTC](https://discuss.elastic.co/t/how-do-i-add-a-second-node/62102/4 "2017-07-05T22:15:20Z")

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