# Force joining cluster after network error **URL:** \ **Category:** Elasticsearch\ **Created:** [January 2, 2019, 10:44am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634 "2019-01-02T10:44:06Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![kamal](https://avatars.discourse-cdn.com/v4/letter/k/a698b9/32.png) [@kamal](https://discuss.elastic.co/u/kamal)\ **Post date:** [January 2, 2019, 10:44am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/1 "2019-01-02T10:44:06Z")
Hi Three of my nodes were on a different switch, got network problem and now I have two clusters, what should I do to make these three nodes, join the real cluster again? ---
**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\ **Post date:** [January 2, 2019, 10:47am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/2 "2019-01-02T10:47:23Z")
How many master-eligible nodes do you have? Have you set `discovery.zen.minimum_master_nodes` correctly [according to these guidelines](https://www.elastic.co/guide/en/elasticsearch/reference/6.5/modules-node.html#split-brain)? ---
**Author:** ![kamal](https://avatars.discourse-cdn.com/v4/letter/k/a698b9/32.png) [@kamal](https://discuss.elastic.co/u/kamal)\ **Post date:** [January 2, 2019, 10:50am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/3 "2019-01-02T10:50:12Z")
All nodes (31 nodes) are master eligible, replica is 0. oops, I didn't set minimum master nodes. ---
**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\ **Post date:** [January 2, 2019, 10:53am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/4 "2019-01-02T10:53:46Z")
In that scenario it should be set to 16. I would however probably recommend instead introducing 3 dedicated master nodes, leave the rest as dedicated data nodes and set it to 2. This generally makes it a lot easier to scale out a cluster. ---
**Author:** ![kamal](https://avatars.discourse-cdn.com/v4/letter/k/a698b9/32.png) [@kamal](https://discuss.elastic.co/u/kamal)\ **Post date:** [January 2, 2019, 10:55am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/5 "2019-01-02T10:55:14Z")
Now, I got two separate clusters, how to make new fake cluster nodes to join real cluster? Should I restart elastic on three nodes? I just unplug new fake master, other nodes joined old cluster. I will change `minimum_master_nodes` as you said. Thanks in advance. ---
**Author:** ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)\ **Post date:** [January 2, 2019, 11:21am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/6 "2019-01-02T11:21:23Z")
> [@kamal](#): > > how to make new fake cluster nodes to join real cluster? Tread carefully here. Any data you wrote while there were two clusters might be lost when you try and merge them together again. There's no guarantee that the data in the "real" cluster will override that in the "fake" one during the merge. It could even result in corrupt indices. If your "real" cluster is healthy (`yellow` or `green` health) then I'd stop all the nodes that formed the "fake" cluster, wipe them, and restart them as empty nodes. At least that way they can't override the "real" data, and then you just have to work out what data needs indexing again because it was sent to the now-wiped "fake" cluster. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [January 30, 2019, 11:21am UTC](https://discuss.elastic.co/t/force-joining-cluster-after-network-error/162634/7 "2019-01-30T11:21:25Z")
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