Kube API Server

Overview

The Kubernetes API Server is the central management entity that exposes the Kubernetes API. All kubectl commands, cluster components, and external clients interact with it.

Why it’s Useful

Detects slow API calls or high error rates.
Identifies request bottlenecks impacting cluster operations.
Ensures cluster remains responsive under load.

What Users Can Do

Monitor API latency and error rates.
Adjust scrape intervals for fine-grained monitoring.
Troubleshoot failed requests and downtime issues.

Steps to Configure

Get the existing ConfigMap.

kubectl get cm opsramp-k8s-infra-metric-user-config -n <agent-installed-namespace> -o yaml

Edit the ConfigMap.

kubectl edit cm opsramp-k8s-infra-metric-user-config -n <agent-installed-namespace>

Locate the apiserver section in ConfigMap.

k8s_cluster:
  enabled: true
  config:
    scrape_interval: "2m"

Update the required parameters.
Save and apply the changes.

Supported Metrics

Metric Name	Description
aggregator_discovery_aggregation_count	Number of aggregated discovery requests served by the API aggregator.
aggregator_unavailable_apiservice	Indicates if an API service registered with the aggregator is currently unavailable.
apiextensions_apiserver_validation_ratcheting_seconds	Time taken by the API extensions server to validate and apply ratcheting for CRD updates.
apiextensions_openapi_v2_regeneration	Tracks regeneration events for OpenAPI V2 specifications by the API extensions server.
apiextensions_openapi_v3_regeneration	Tracks regeneration events for OpenAPI V3 specifications by the API extensions server.
apiserver_storage_objects	Total number of stored objects per resource type in etcd.
apiserver_admission_controller_admission_duration_seconds	Time taken by admission controllers to admit or deny incoming API requests.
apiserver_admission_step_admission_duration_seconds	Duration of each admission control step within the API server request flow.
apiserver_admission_step_admission_duration_seconds_summary	Summary statistics of admission step durations within the API server.
apiserver_audit_event	Number of audit events generated by the API server.
apiserver_audit_requests_rejected	Count of audit events rejected due to misconfiguration or buffer overflow.
apiserver_authorization_decisions	Number of authorization decisions made (allowed or denied) by the API server.
apiserver_cache_list_fetched_objects	Number of objects fetched during list operations served from cache.
apiserver_cache_list_returned_objects	Number of objects returned by list operations from the cache.
apiserver_cache_list	Tracks cache hit and miss rates for API list requests.
apiserver_cel_compilation_duration_seconds	Duration to compile CEL (Common Expression Language) expressions in admission webhooks.
apiserver_cel_evaluation_duration_seconds	Duration to evaluate CEL expressions during admission control.
apiserver_client_certificate_expiration_seconds	Time remaining before client certificates used by the API server expire.
apiserver_clusterip_repair_reconcile_errors	Number of errors encountered while reconciling cluster IP allocations.
apiserver_current_inflight_requests	Number of active requests currently being processed by the API server.
apiserver_current_inqueue_requests	Number of requests currently waiting in the API server request queue.
apiserver_envelope_encryption_dek_cache_fill_percent	Percentage of the encryption key cache filled for envelope encryption.
apiserver_flowcontrol_current_executing_requests	Number of currently executing requests under API Priority and Fairness (APF) control.
apiserver_flowcontrol_current_executing_seats	Number of active execution "seats" used by requests in APF.
apiserver_flowcontrol_current_inqueue_requests	Number of queued requests under API Priority and Fairness control.
apiserver_flowcontrol_current_inqueue_seats	Number of queue "seats" occupied by waiting requests.
apiserver_flowcontrol_current_limit_seats	Current limit of total execution seats available for requests.
apiserver_flowcontrol_demand_seats_average	Average number of seats demanded by incoming requests over time.
apiserver_flowcontrol_demand_seats_high_watermark	Highest observed number of seats demanded by requests.
apiserver_flowcontrol_demand_seats_stdev	Standard deviation of request seat demand over time.
apiserver_flowcontrol_dispatch_r	Dispatch rate of requests under APF scheduling.
apiserver_flowcontrol_dispatched_requests	Total number of dispatched requests under APF.
apiserver_flowcontrol_priority_level_request_utilization	Ratio of utilized vs. available request concurrency per priority level.
apiserver_flowcontrol_priority_level_seat_utilization	Utilization rate of available request execution seats per priority level.
apiserver_flowcontrol_read_vs_write_current_requests	Tracks ratio of concurrent read vs. write operations in APF.
apiserver_flowcontrol_request_concurrency_in_use	Number of concurrent requests currently in execution.
apiserver_flowcontrol_request_execution_seconds	Duration of request execution for API Priority and Fairness flows.
apiserver_flowcontrol_request_queue_length_after_enqueue	Queue length after new requests are enqueued.
apiserver_flowcontrol_request_wait_duration_seconds	Time spent by requests waiting in the queue before execution.
apiserver_flowcontrol_seat_fair_frac	Fraction of seats allocated fairly among competing requests.
apiserver_flowcontrol_target_seats	Target number of execution seats under APF configuration.
apiserver_flowcontrol_upper_limit_seats	Upper threshold for concurrent execution seats.
apiserver_flowcontrol_watch_count_samples	Number of watch event samples processed by APF.
apiserver_flowcontrol_work_estimated_seats	Estimated number of seats required per unit of request work.
apiserver_init_events	Initialization events triggered during API server startup.
apiserver_kube_aggregator_x509_insecure_sha1	Count of certificates using insecure SHA1 signatures detected by the aggregator.
apiserver_kube_aggregator_x509_missing_san	Number of certificates missing Subject Alternative Name (SAN) entries.
apiserver_longrunning_requests	Number of currently active long-running requests (e.g., watch streams).
apiserver_nodeport_repair_reconcile_errors	Errors encountered during NodePort repair reconciliation.
apiserver_request_aborts	Number of API requests aborted before completion.
apiserver_request_body_size_bytes	Distribution of API request body sizes in bytes.
apiserver_request_duration_seconds	Overall latency of API requests from receipt to completion.
apiserver_request_filter_duration_seconds	Time spent filtering requests by admission or authorization layers.
apiserver_request_post_timeout	Number of requests that timed out after processing began.
apiserver_request_sli_duration_seconds	Service Level Indicator (SLI) for request latency duration.
apiserver_request_terminations	Number of API requests forcefully terminated by the server.
apiserver_request_timestamp_comparison_time	Latency in comparing timestamps during request validation.
apiserver_request	Total count of API requests received by the server.
apiserver_response_sizes	Distribution of response payload sizes returned by the API server.
apiserver_selfrequest	Internal requests made by the API server to itself for health or sync operations.
apiserver_storage_data_key_generation_duration_seconds	Time taken to generate data encryption keys for storage operations.
apiserver_storage_data_key_generation_failures	Number of failures during encryption key generation for data storage.
apiserver_storage_envelope_transformation_cache_misses	Number of cache misses during envelope encryption/decryption transformations.
apiserver_storage_events_received	Total number of etcd storage events received by the API server.
apiserver_storage_list_evaluated_objects	Number of objects evaluated by list operations in storage requests.
apiserver_storage_list_fetched_objects	Number of objects fetched by list operations from etcd storage.
workqueue_work_duration_seconds	Time taken by workqueue tasks to complete processing.