# Elastic Search restart
**URL:** https://discuss.elastic.co/t/elastic-search-restart/76699
**Category:** Elasticsearch
**Created:** [February 27, 2017, 9:59pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699 "2017-02-27T21:59:40Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@elk12](https://discuss.elastic.co/u/elk12)
#### Post date: [February 27, 2017, 9:59pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/1 "2017-02-27T21:59:40Z")
Hello Folks,
I have 3 elastic(5.1.2) nodes (01,02,03), of which 01,02 are in Datacenter1 and 03 is in Datacenter2. the elasticsearch.yml on all 3 has the below settings
1. Cluster name is same across all - it is cluster01
2. host and node names specific to the Linux server , like node01 ,node02 and node03.
3. discovery.zen.ping.unicast.hosts: ["node01", "node02" , "node03"]
4. We have kibana pointing to node01.
I have few questions here
1. In the above scenario is there a Master ? and slave ?
2. what is the best way to stop/start ES ? 1 node at a time , we tried to stop/start 3,2,1 , the nodes threw errors like no master etc
path: /\_bulk, params: {}org.elasticsearch.cluster.block.ClusterBlockException: blocked by: [SERVICE\_UNAVAILABLE/2/no master];
3. is it recommended to switch to master/slave mode ? Currently this set up of ours is running fine,wanted to make sure the stop/start of nodes to minimize errors.
Any feedback/recommendations will be helpful
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [February 27, 2017, 10:06pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/2 "2017-02-27T22:06:18Z")
1. Check `_cat/master`
2. What settings have you applied to the cluster?
3. There is no such thing as a slave, only master and master-eligible.
---
### Author:  [@elk12](https://discuss.elastic.co/u/elk12)
#### Post date: [February 27, 2017, 10:22pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/3 "2017-02-27T22:22:54Z")
I checked the \_cat/master , on all 3 nodes , it returns node01. So that means node01 is master and other 2 master-eligible ?
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [February 27, 2017, 10:26pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/4 "2017-02-27T22:26:22Z")
Yep 🙂
---
### Author:  [@elk12](https://discuss.elastic.co/u/elk12)
#### Post date: [February 27, 2017, 10:28pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/5 "2017-02-27T22:28:41Z")
That helps , thanks a lot
so for any maintenance or anything we need to start/stop node1 first before proceeding to others. is that a correct statement in my scenario
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [February 27, 2017, 10:29pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/6 "2017-02-27T22:29:40Z")
No, you should be able to restart any single node in that cluster and not lose access to the cluster.
What settings have you set in your config?
---
### Author:  [@elk12](https://discuss.elastic.co/u/elk12)
#### Post date: [February 27, 2017, 10:32pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/7 "2017-02-27T22:32:55Z")
I have below settings and was wondering why did that error message came like no master ( meaning it was refering to my node01) and no data was being lost ?
[cluster.name](http://cluster.name): cluster01
[node.name](http://node.name): node01
path.data: /opt/data/elasticsearch-5.1.2
path.logs: /opt/logs/elasticsearch-5.1.2
bootstrap.memory\_lock: true
network.host: node01
http.port: 9200
discovery.zen.ping.unicast.hosts: ["node01", "node02" , "node03"]
discovery.zen.minimum\_master\_nodes: 3
http.cors.enabled: true
http.cors.allow-origin: "\*"
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [February 27, 2017, 11:35pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/8 "2017-02-27T23:35:11Z")
> [@elk12](#):
>
> discovery.zen.minimum\_master\_nodes: 3
That is why. Change that to 2.
---
### Author:  [@elk12](https://discuss.elastic.co/u/elk12)
#### Post date: [February 28, 2017, 2:07pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/10 "2017-02-28T14:07:03Z")
After going through the documentation , it says below.
This setting must be set to a quorum of your master eligible nodes. It is recommended to avoid having only two master eligible nodes, since a quorum of two is two. Therefore, a loss of either master eligible node will result in an inoperable cluster
Any thoughts ? And also how did you come up with 2 ?
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [February 28, 2017, 7:42pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/11 "2017-02-28T19:42:28Z")
The docs also say `(number master eligible nodes / 2) + 1`.
So `(3 / 2) + 1 = 2`, when you round up.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [March 28, 2017, 7:42pm UTC](https://discuss.elastic.co/t/elastic-search-restart/76699/12 "2017-03-28T19:42:27Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.