Index Instances

An Index can have multiple instances for:

• scalability/ load balancing
• cold standby/ backups
• migrations/ updates
• A/ B tests

Each of them can be configured separately. Currently, there are two instance types supported elastic_7, opensearch_1. The first instance will be created by default when a new index is created and is in state ACTIVE. More Instances can be added, but each of them receive the initial state ACTIVE_AFTER_REBUILD and create a index notification to inform the index about changes that will be applied after rebuild. The index instance automatically switch the state ACTIVE_AFTER_REBUILD to ACTIVE after successful index rebuild. If there are more than one instance configured, then one scheduling option round-robin, random, first can be selected. Otherwise, this option is disabled.

state/action	search	feed	index-rebuild
ACTIVE	✅	✅	✅
STANDBY	❌	✅	✅
ACTIVE_AFTER_REBUILD	❌	❌	✅
INACTIVE	❌	❌	✅

action	description
search	Search the index via search, suggest
feed	Feed the index via full or delta updates, should not modify index mapping
index-rebuild	Rebuild the index with full feed and latest mapping

{
	"loadbalancerStrategy": "round-robin (default), random, first",
	"instances": [
		{
			"id": "node1",
			"type": "elastic_7",
			"state": "ACTIVE",
			"endpoint": "https://aws.com/my-index"
		},
		{
			"id": "node2",
			"type": "elastic_7",
			"state": "STANDBY",
			"endpoint": "https://cloud.google.com/my-index"
		},
		{
			"id": "node3",
			"type": "opensearch_1",
			"state": "ACTIVE_AFTER_REBUILD",
			"endpoint": "https://localhost:9200/my-index"
		}
	]
}