Setting Up a Three-Node Elasticsearch Cluster on CentOS 7
Prerequisites
Java Runtime Environment
Install the Java 8 runtime environment:
yum install -y java-1.8.0
Swap Deactivation
Disable swap memory to ensure stability:
# Edit fstab to comment out swap entries
vim /etc/fstab
# Immediately disable all swap partitions
swapoff -a
System Resource Tuning
File Descriptors
Increase the open file descriptor limit in /etc/security/limits.conf:
* soft nofile 65536
* hard nofile 65536
Virtual Memory Areas
Adjust the maximum map count in /etc/sysctl.conf:
vm.max_map_count = 655360
Apply the changes:
sysctl -p
Thread Count
Set the process thread limit in /etc/security/limits.conf:
* soft nproc 65535
* hard nproc 65535
Installation and Configuration
Fetch and Extract
Download the Elasticsearch 7.10.0 package and extract it:
wget https://repo.huaweicloud.com/elasticsearch/7.10.0/elasticsearch-7.10.0-linux-x86_64.tar.gz
tar -zxvf elasticsearch-7.10.0-linux-x86_64.tar.gz -C /opt/
Node Configuration
Edit the elasticsearch.yml file located in the config directory. Below is a sample configuration for node-1. Repeat this for the other two nodes, changing node.name and network.host accordingly.
cluster.name: prod-search-cluster
node.name: node-1
node.master: true
node.data: true
path.data: /var/lib/elasticsearch
data
data
path.logs: /var/log/elasticsearch
network.host: 0.0.0.0
http.port: 9200
transport.tcp.port: 9300
http.cors.enabled: true
http.cors.allow-origin: "*"
discovery.zen.ping.unicast.hosts: ["192.168.1.10:9300", "192.168.1.11:9300", "192.168.1.12:9300"]
Service Management
Create a systemd unit file /etc/systemd/system/elasticsearch.service to manage the service:
[Unit]
Description=Elasticsearch Search Engine
After=network.target
[Service]
Type=simple
User=elasticsearch
Group=elasticsearch
LimitNOFILE=65536
LimitMEMLOCK=infinity
ExecStart=/opt/elasticsearch-7.10.0/bin/elasticsearch
Restart=on-failure
[Install]
WantedBy=multi-user.target
Reload the daemon and start the service:
systemctl daemon-reload
systemctl start elasticsearch
systemctl enable elasticsearch
Verification
Check the cluster membership and health by querying the nodes endpoint:
curl http://localhost:9200/_cat/nodes?v
