# Remove master nodes from elasticsearch cluster
**URL:** https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821
**Category:** Elasticsearch
**Created:** [March 6, 2024, 9:52am UTC](https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821 "2024-03-06T09:52:32Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@mukularora89](https://discuss.elastic.co/u/mukularora89)
#### Post date: [March 6, 2024, 9:52am UTC](https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821/1 "2024-03-06T09:52:33Z")
Hi,
We have a requirement where we need to upgrade OS and for that Elasticsearch will be fresh installed on the nodes. I have a question related to master nodes removal.
We have 3 master nodes as part of the cluster. What approach can I take for removing master nodes from cluster for OS migration and then adding them back after OS migration is done.
**Approach 1** - Remove one master node at a time for OS migration
**Questions**
1. Can I remove one master node, following this [blog](https://www.elastic.co/guide/en/elasticsearch/reference/current/add-elasticsearch-nodes.html#modules-discovery-removing-nodes) and let the elasticsearch cluster run with 2 master nodes and add the removed master nodes once OS migration is done?
2. Will this lead to split brain condition with 2 master nodes?
3. Can elasticsearch cluster will work in mixed OS mode? i.e. few master node in CentOS7 and few in RHEL9
**Approach 2** - Add more master nodes to cluster with new OS and then start removing master nodes with old OS
**Questions**
1. Do I need to add more master nodes (with required OS) into cluster and then do the removal process one by one of master node (with old OS)?
2. If yes, what is the initial number of master nodes I have to add before start removal process considering we have 3 initial master nodes.
3. Also how these new master nodes will be added to the voting configuration?
4. Do I also need to add master nodes list "discovery.seed\_hosts" for data nodes for this approach?
Please let me know your thoughts on the above approaches and which will work better.
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### Author:  [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)
#### Post date: [March 6, 2024, 11:12am UTC](https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821/2 "2024-03-06T11:12:15Z")
> [@mukularora89](#):
>
> Can I remove one master node,
Yes.
> [@mukularora89](#):
>
> Will this lead to split brain condition
No.
> [@mukularora89](#):
>
> Can elasticsearch cluster will work in mixed OS mode?
Probably yes although we don't test it.
> [@mukularora89](#):
>
> Do I need to add more master nodes
Either approach works.
> [@mukularora89](#):
>
> If yes, what is the initial number of master nodes I have to add
Up to you. You could do it one-by-one or in larger steps.
> [@mukularora89](#):
>
> Also how these new master nodes will be added to the voting configuration?
It's automatic.
> [@mukularora89](#):
>
> Do I also need to add master nodes list "discovery.seed\_hosts"
Yes.
---
### Author:  [@mukularora89](https://discuss.elastic.co/u/mukularora89)
#### Post date: [March 6, 2024, 11:41am UTC](https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821/3 "2024-03-06T11:41:58Z")
Thanks David. So what I am getting from the replies that Approach 1 will work in my use case. Also with approach 1 do I need to add master node to voting configuration exclusion list, if I am removing one master at a time in a 3 master node cluster
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### Author:  [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)
#### Post date: [March 6, 2024, 1:20pm UTC](https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821/4 "2024-03-06T13:20:14Z")
> [@mukularora89](#):
>
> do I need to add master node to voting configuration exclusion list, if I am removing one master at a time
Probably not, as long as you don't remove multiple master nodes too quickly.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [April 3, 2024, 1:20pm UTC](https://discuss.elastic.co/t/remove-master-nodes-from-elasticsearch-cluster/354821/5 "2024-04-03T13:20:39Z")
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