Metrics

Shard exposes a few metrics to give you better visibility into the state of your cluster. Those metrics are exposed via ZIO Metrics, which allows you to use the backend of your choice.

Metrics that depend on a role are tagged with role (the role name) so you can break them down per role. The shard-level Shard Manager gauges are additionally tagged with pod_address.

Shard Manager Metrics

• shard.pods (gauge, tagged with role): Number of pods currently registered
• shard.shards_assigned (gauge, tagged with role and pod_address): Number of shards currently assigned to a pod
• shard.shards_unassigned (gauge, tagged with role): Number of shards currently not assigned to any pod
• shard.rebalances (counter, tagged with role): Number of rebalances that have occurred
• shard.pod_health_checked (counter, tagged with pod_address): Number of times the health of a pod has been checked

Pod Metrics

• shard.shards (gauge, tagged with role): Number of shards currently assigned to the pod
• shard.entities (gauge, tagged with role and type): Number of entities currently running on the pod
• shard.singletons (gauge, tagged with role and singleton_name): Number of singletons currently running on the pod