ElasticSearch ElasticSearch Cluster Management & Administration 3

Question 1

Which Elasticsearch API is used to manually reroute a shard to a different node in the cluster?

Accepted Answer

POST /_cluster/reroute

Answer

POST /_cluster/allocation/explain

Answer

PUT /_cluster/settings

Answer

POST /_nodes/reroute

Question 2

What is the recommended way to gracefully decommission a node from an Elasticsearch cluster without losing data?

Accepted Answer

Set cluster.routing.allocation.exclude._name to the node's name

Answer

Use DELETE /_nodes/{node_id} to remove it safely

Answer

Set node.data: false in the config and restart the node

Answer

Remove the node from discovery.seed_hosts and restart the cluster

Question 3

What is the primary purpose of Elasticsearch Index Lifecycle Management (ILM)?

Accepted Answer

Automatically transitioning indices through hot, warm, cold, and delete phases based on policies

Answer

Managing user access permissions to indices over time

Answer

Balancing index distribution across nodes as indices age

Answer

Managing index mapping schema updates as data evolves

Question 4

What information does the GET /_cat/shards API provide?

Accepted Answer

Per-shard details including state, size, document count, and node assignment

Answer

A summary list of all indices and their total shard counts

Answer

Shard allocation recommendations generated by the cluster

Answer

Performance statistics about query throughput per shard

Question 5

What defines a 'hot-warm' architecture in Elasticsearch?

Accepted Answer

Using SSD nodes for recent data and HDD nodes for older data to balance performance and cost

Answer

A configuration where some nodes handle writes while others handle reads

Answer

A cluster topology that places primary and replica shards on separate hardware tiers

Answer

A deployment model with active and standby clusters for automatic failover

Question 6

Which Elasticsearch API provides a detailed explanation of why a specific shard is unassigned or in its current allocation state?

Accepted Answer

GET /_cluster/allocation/explain

Answer

GET /_cluster/stats

Answer

GET /_cat/shards?v

Answer

GET /_nodes/stats/indices

Question 7

What is the default behavior of Elasticsearch when a previously unavailable data node rejoins the cluster?

Accepted Answer

Elasticsearch automatically re-integrates the node and rebalances shards across it

Answer

The node must be manually re-added to the cluster configuration file

Answer

The node starts with no data until full replication from scratch completes

Answer

The cluster requires a full restart to accept and recognize the returning node