Multi Master configuration

Elastic Stack Elasticsearch
1

Hi Team,

I'm currently trying to configure an elastic search cluster with 2 masters and 3 data nodes
My cluster is working 1 Master and 3 data Node.

root@ELK-Master1:~# curl http://IP:9200/_cat/nodes?v
ip heap.percent ram.percent cpu load_1m load_5m load_15m node.role master name
host1 24 8 0 0.00 0.00 0.00 di - ELK-Slave1
host2 14 8 0 0.00 0.00 0.00 di - ELK-Slave3
host3 29 8 0 0.03 0.01 0.00 di - ELK-Slave2
Master1 14 13 47 3.77 3.68 2.61 mdi * ELK-Master1

But the second Master couldn't add into Master 1.

Master1 elasticsearch.yaml:
cluster.name: PreProd-Cluster
node.name: ELK-Master1
node.master: true
path.data: /var/lib/elasticsearch
path.logs: /var/log/elasticsearch
network.host: Master1
http.port: 9200
discovery.seed_hosts: ["Master1, Master2"]
cluster.initial_master_nodes: ["Master1, Master2"]

Master2 elasticsearch.yaml:
cluster.name: PreProd-Cluster
node.name: ELK-Master1
node.master: true
path.data: /var/lib/elasticsearch
path.logs: /var/log/elasticsearch
network.host: Master1
http.port: 9200
discovery.zen.minimum_master_nodes: 2
discovery.seed_hosts: ["Master1, Master2"]
cluster.initial_master_nodes: ["Master1, Master2"]

2

Elasticsearch is operates in a clustered mode and is not a master-slave system as indicated by your node names. As it relies on consensus algorithms, you should always aim to have at least 3 master-eligible nodes in your cluster. Having 2 master eligible nodes in a cluster is a bad idea as the cluster will be in a red state if any of them go down as there is no majority available to elect a new master.

As you are on the latest version I believe you simply leave the current single master node in the config and then add the new master eligible node(s).