Elasticsearch Multi-Node Cluster on AlmaLinux 9

Architecture

• node-1 (master-eligible + data): 192.168.1.10
• node-2 (master-eligible + data): 192.168.1.11
• node-3 (master-eligible + data): 192.168.1.12

Step 1 – Install Elasticsearch on all nodes

See Install Elasticsearch on AlmaLinux 9.

Step 2 – Configure node-1 (/etc/elasticsearch/elasticsearch.yml)

cluster.name: production-cluster
node.name: node-1
node.roles: [ master, data, ingest ]

path.data: /var/lib/elasticsearch
path.logs: /var/log/elasticsearch

network.host: 192.168.1.10
http.port: 9200
transport.port: 9300

discovery.seed_hosts:
  - 192.168.1.10
  - 192.168.1.11
  - 192.168.1.12

cluster.initial_master_nodes:
  - node-1
  - node-2
  - node-3

xpack.security.enabled: true
xpack.security.transport.ssl.enabled: true
xpack.security.transport.ssl.verification_mode: certificate
xpack.security.transport.ssl.keystore.path: /etc/elasticsearch/certs/transport.p12
xpack.security.transport.ssl.truststore.path: /etc/elasticsearch/certs/transport.p12

Step 3 – Generate certificates (on node-1)

/usr/share/elasticsearch/bin/elasticsearch-certutil ca
/usr/share/elasticsearch/bin/elasticsearch-certutil cert --ca elastic-stack-ca.p12

Distribute transport.p12 to all nodes.

Step 4 – Start all nodes

systemctl start elasticsearch

Step 5 – Check cluster health

curl -u elastic:YourPassword --cacert /etc/elasticsearch/certs/http_ca.crt \
    'https://localhost:9200/_cluster/health?pretty'

Expected: "status": "green", "number_of_nodes": 3.