Elastic Stack 8 : Elasticsearch Cluster

	Configure Elasticsearch Cluster. This example shows to configure Elasticsearch Cluster with 3 Nodes and configure each Node is Master Eligible Node and Data Node (default). Each node serves one or more purpose, refer to details below. ⇒ https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html
[1]	Install and Run Elasticsearch on all Nodes. (installation only)
[2]	On the 1st node, start Elasticsearch and generate an enrollment token for other nodes.

[root@node01 ~]#  vi /etc/elasticsearch/elasticsearch.yml # line 17 : uncomment and change (any name you like) cluster.name:  elastic-cluster # line 56 : uncomment and change (listen all) network.host:  0.0.0.0 [root@node01 ~]#  systemctl enable --now elasticsearch [root@node01 ~]#  /usr/share/elasticsearch/bin/elasticsearch-create-enrollment-token -s node eyJ2ZXIiOiI4LjUuMyIsImFkciI6WyIxMC4wLjAuNTE6OTIwMCJdLCJmZ3IiOiJjNjk2ZGIyMmFjMmY4Y2U2ZWQ4NTBjMTQ5ODMyN2VmNmE3ZmNiMDZiMjIzOTNlNTIxMjEwNTgyMzg0NjA3NTRkIiwia2V5IjoiVXVHODlZUUJCeElZUm9NSlBEMmk6YUFyT1E4V05SME9qZTJGY2hiZGtJUSJ9

[3]	If Firewalld is running, allow service ports on all Nodes.

[root@node01 ~]#  firewall-cmd --add-port={9200/tcp,9300/tcp} success [root@node01 ~]#  firewall-cmd --runtime-to-permanent success

[4]	On other nodes, join in cluster with an enrollment token generated on the 1st node above.

[root@node02 ~]# /usr/share/elasticsearch/bin/elasticsearch-reconfigure-node --enrollment-token \ eyJ2ZXIiOiI4LjUuMyIsImFkciI6WyIxMC4wLjAuNTE6OTIwMCJdLCJmZ3IiOiJjNjk2ZGIyMmFjMmY4Y2U2ZWQ4NTBjMTQ5ODMyN2VmNmE3ZmNiMDZiMjIzOTNlNTIxMjEwNTgyMzg0NjA3NTRkIiwia2V5IjoiVXVHODlZUUJCeElZUm9NSlBEMmk6YUFyT1E4V05SME9qZTJGY2hiZGtJUSJ9 This node will be reconfigured to join an existing cluster, using the enrollment token that you provided. This operation will overwrite the existing configuration. Specifically: - Security auto configuration will be removed from elasticsearch.yml - The [certs] config directory will be removed - Security auto configuration related secure settings will be removed from the elasticsearch.keystore Do you want to continue with the reconfiguration process [y/N]y [root@node02 ~]#  vi /etc/elasticsearch/elasticsearch.yml # line 17 : uncomment and specify the same name with 1st node cluster.name:  elastic-cluster # line 56 : uncomment and change (listen all) network.host:  0.0.0.0 [root@node02 ~]#  systemctl enable --now elasticsearch

[5]	Verify Cluster status. If the status is green, That's OK.

[root@node01 ~]#  curl -u elastic --cacert /etc/elasticsearch/certs/http_ca.crt https://node01.srv.world:9200/_cat/nodes?v Enter host password for user 'elastic': ip heap.percent ram.percent cpu load_1m load_5m load_15m node.role master name 10.0.0.52 30 97 2 0.00 0.04 0.02 cdfhilmrstw - node02.srv.world 10.0.0.51 37 96 1 0.16 0.06 0.05 cdfhilmrstw * node01.srv.world 10.0.0.53 25 97 5 0.06 0.07 0.02 cdfhilmrstw - node03.srv.world [root@node01 ~]#  curl -u elastic --cacert /etc/elasticsearch/certs/http_ca.crt https://node01.srv.world:9200/_cluster/health?pretty Enter host password for user 'elastic': { "cluster_name" : "elastic-cluster", "status" : "green", "timed_out" : false, "number_of_nodes" : 3, "number_of_data_nodes" : 3, "active_primary_shards" : 2, "active_shards" : 4, "relocating_shards" : 0, "initializing_shards" : 0, "unassigned_shards" : 0, "delayed_unassigned_shards" : 0, "number_of_pending_tasks" : 0, "number_of_in_flight_fetch" : 0, "task_max_waiting_in_queue_millis" : 0, "active_shards_percent_as_number" : 100.0 }