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Cluster administrators can view the following metrics for Knative Serving components.

Activator metrics

You can use the following metrics to understand how applications respond when traffic passes through the activator.

Metric name Description Type Tags Unit

request_concurrency

The number of concurrent requests that are routed to the activator, or average concurrency over a reporting period.

Gauge

configuration_name, container_name, namespace_name, pod_name, revision_name, service_name

Integer (no units)

request_count

The number of requests that are routed to activator. These are requests that have been fulfilled from the activator handler.

Counter

configuration_name, container_name, namespace_name, pod_name, response_code, response_code_class, revision_name, service_name,

Integer (no units)

request_latencies

The response time in milliseconds for a fulfilled, routed request.

Histogram

configuration_name, container_name, namespace_name, pod_name, response_code, response_code_class, revision_name, service_name

Milliseconds

Autoscaler metrics

The autoscaler component exposes a number of metrics related to autoscaler behavior for each revision. For example, at any given time, you can monitor the targeted number of pods the autoscaler tries to allocate for a service, the average number of requests per second during the stable window, or whether the autoscaler is in panic mode if you are using the Knative pod autoscaler (KPA).

Metric name Description Type Tags Unit

desired_pods

The number of pods the autoscaler tries to allocate for a service.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

excess_burst_capacity

The excess burst capacity served over the stable window.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

stable_request_concurrency

The average number of requests for each observed pod over the stable window.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

panic_request_concurrency

The average number of requests for each observed pod over the panic window.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

target_concurrency_per_pod

The number of concurrent requests that the autoscaler tries to send to each pod.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

stable_requests_per_second

The average number of requests-per-second for each observed pod over the stable window.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

panic_requests_per_second

The average number of requests-per-second for each observed pod over the panic window.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

target_requests_per_second

The number of requests-per-second that the autoscaler targets for each pod.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

panic_mode

This value is 1 if the autoscaler is in panic mode, or 0 if the autoscaler is not in panic mode.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

requested_pods

The number of pods that the autoscaler has requested from the Kubernetes cluster.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

actual_pods

The number of pods that are allocated and currently have a ready state.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

not_ready_pods

The number of pods that have a not ready state.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

pending_pods

The number of pods that are currently pending.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

terminating_pods

The number of pods that are currently terminating.

Gauge

configuration_name, namespace_name, revision_name, service_name

Integer (no units)

Go runtime metrics

Each Knative Serving control plane process emits a number of Go runtime memory statistics (MemStats).

The name tag for each metric is an empty tag.

Metric name Description Type Tags Unit

go_alloc

The number of bytes of allocated heap objects. This metric is the same as heap_alloc.

Gauge

name

Integer (no units)

go_total_alloc

The cumulative bytes allocated for heap objects.

Gauge

name

Integer (no units)

go_sys

The total bytes of memory obtained from the operating system.

Gauge

name

Integer (no units)

go_lookups

The number of pointer lookups performed by the runtime.

Gauge

name

Integer (no units)

go_mallocs

The cumulative count of heap objects allocated.

Gauge

name

Integer (no units)

go_frees

The cumulative count of heap objects that have been freed.

Gauge

name

Integer (no units)

go_heap_alloc

The number of bytes of allocated heap objects.

Gauge

name

Integer (no units)

go_heap_sys

The number of bytes of heap memory obtained from the operating system.

Gauge

name

Integer (no units)

go_heap_idle

The number of bytes in idle, unused spans.

Gauge

name

Integer (no units)

go_heap_in_use

The number of bytes in spans that are currently in use.

Gauge

name

Integer (no units)

go_heap_released

The number of bytes of physical memory returned to the operating system.

Gauge

name

Integer (no units)

go_heap_objects

The number of allocated heap objects.

Gauge

name

Integer (no units)

go_stack_in_use

The number of bytes in stack spans that are currently in use.

Gauge

name

Integer (no units)

go_stack_sys

The number of bytes of stack memory obtained from the operating system.

Gauge

name

Integer (no units)

go_mspan_in_use

The number of bytes of allocated mspan structures.

Gauge

name

Integer (no units)

go_mspan_sys

The number of bytes of memory obtained from the operating system for mspan structures.

Gauge

name

Integer (no units)

go_mcache_in_use

The number of bytes of allocated mcache structures.

Gauge

name

Integer (no units)

go_mcache_sys

The number of bytes of memory obtained from the operating system for mcache structures.

Gauge

name

Integer (no units)

go_bucket_hash_sys

The number of bytes of memory in profiling bucket hash tables.

Gauge

name

Integer (no units)

go_gc_sys

The number of bytes of memory in garbage collection metadata.

Gauge

name

Integer (no units)

go_other_sys

The number of bytes of memory in miscellaneous, off-heap runtime allocations.

Gauge

name

Integer (no units)

go_next_gc

The target heap size of the next garbage collection cycle.

Gauge

name

Integer (no units)

go_last_gc

The time that the last garbage collection was completed in Epoch or Unix time.

Gauge

name

Nanoseconds

go_total_gc_pause_ns

The cumulative time in garbage collection stop-the-world pauses since the program started.

Gauge

name

Nanoseconds

go_num_gc

The number of completed garbage collection cycles.

Gauge

name

Integer (no units)

go_num_forced_gc

The number of garbage collection cycles that were forced due to an application calling the garbage collection function.

Gauge

name

Integer (no units)

go_gc_cpu_fraction

The fraction of the available CPU time of the program that has been used by the garbage collector since the program started.

Gauge

name

Integer (no units)