NIFI-11036: Add Cluster Summary Metrics to Prometheus endpoint

[mattyb149]

Summary

NIFI-11036

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[MikeThomsen]

@mattyb149 I started NiFi on this branch and didn't see any of the metrics you added exposed on the metrics endpoint. Do these only get generated in clustered mode?

[taz1988]

I didn't find any error, if I use https://localhost:8443/nifi-api/flow/metrics/prometheus?includedRegistries=CLUSTER I got the data:

# HELP cluster_is_clustered Whether this NiFi instance is clustered. Values are 0 or 1
# TYPE cluster_is_clustered gauge
cluster_is_clustered{instance="7f34c4ca-b48e-489c-8533-ddd9882c4a43",} 1.0
# HELP cluster_connected_node_count The number of connected nodes in this cluster
# TYPE cluster_connected_node_count gauge
cluster_connected_node_count{instance="7f34c4ca-b48e-489c-8533-ddd9882c4a43",connected_nodes="3 / 3",} 3.0
cluster_connected_node_count{instance="7f34c4ca-b48e-489c-8533-ddd9882c4a43",connected_nodes="2 / 3",} 2.0
# HELP cluster_is_connected_to_cluster Whether this NiFi instance is connected to a cluster. Values are 0 or 1
# TYPE cluster_is_connected_to_cluster gauge
cluster_is_connected_to_cluster{instance="7f34c4ca-b48e-489c-8533-ddd9882c4a43",} 1.0
# HELP cluster_total_node_count The total number of nodes in this cluster
# TYPE cluster_total_node_count gauge
cluster_total_node_count{instance="7f34c4ca-b48e-489c-8533-ddd9882c4a43",} 3.0

👍

[taz1988]

+1

[shayki5]

Can you add it to /metrics endpoint? (which available when PrometheusReportingTask is enabled)

[shayki5]

@taz1988 How can you use this endpoint in Prometheus? which authentication you need?

[uxapj]

How can I request an improvement on this implementation?
As @shayki5 asked, we would love to see this in the /metrics endpoint that is generated from the PrometheusReportingTask...