Kubernetes API Server

Plugin: go.d.plugin Module: k8s_apiserver

Overview

This collector monitors Kubernetes API Server health, performance, and request metrics.

It collects metrics from the kube-apiserver's /metrics endpoint, providing insights into:

• Request rates, latencies, and error rates
• Current inflight and long-running requests
• Admission controller and webhook performance
• etcd backend health and object counts
• Controller work queue depths and latencies
• Authentication and audit events
• Go runtime and process metrics

The collector scrapes Prometheus-format metrics from the Kubernetes API Server's metrics endpoint. Authentication is typically done using a ServiceAccount bearer token.

This collector is supported on all platforms.

This collector supports collecting metrics from multiple instances of this integration.

The ServiceAccount used must have permissions to access the /metrics endpoint. In most clusters, this requires cluster-admin or a custom ClusterRole with metrics access.

Kubernetes API Server can be monitored further using the following other integrations:

• Kubelet
• Kubeproxy
• Kubernetes Cluster State
• Kubernetes Containers
• CoreDNS

Default Behavior

Auto-Detection

When running inside a Kubernetes cluster, the collector attempts to connect to https://kubernetes.default.svc:443/metrics using the pod's ServiceAccount token.

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Setup

You can configure the k8s_apiserver collector in two ways:

Method	Best for	How to
UI	Fast setup without editing files	Go to Nodes → Configure this node → Collectors → Jobs, search for k8s_apiserver, then click + to add a job.
File	If you prefer configuring via file, or need to automate deployments (e.g., with Ansible)	Edit go.d/k8s_apiserver.conf and add a job.

important

UI configuration requires paid Netdata Cloud plan.

Prerequisites

ServiceAccount with metrics access

The Netdata pod must have a ServiceAccount with permissions to read metrics from the API server. You can create a ClusterRole and ClusterRoleBinding for this purpose.

Configuration

Options

The following options can be defined globally: update_every, autodetection_retry.

Config options

Group	Option	Description	Default	Required
Collection	update_every	Data collection interval (seconds).	1	no
	autodetection_retry	Autodetection retry interval (seconds). Set 0 to disable.	0	no
Target	url	Target endpoint URL.	https://kubernetes.default.svc:443/metrics	yes
	timeout	HTTP request timeout (seconds).	2	no
HTTP Auth	username	Username for Basic HTTP authentication.		no
	password	Password for Basic HTTP authentication.		no
	bearer_token_file	Path to a file containing a bearer token (used for Authorization: Bearer).	/var/run/secrets/kubernetes.io/serviceaccount/token	no
TLS	tls_skip_verify	Skip TLS certificate and hostname verification (insecure).	no	no
	tls_ca	Path to CA bundle used to validate the server certificate.	/var/run/secrets/kubernetes.io/serviceaccount/ca.crt	no
	tls_cert	Path to client TLS certificate (for mTLS).		no
	tls_key	Path to client TLS private key (for mTLS).		no
Proxy	proxy_url	HTTP proxy URL.		no
	proxy_username	Username for proxy Basic HTTP authentication.		no
	proxy_password	Password for proxy Basic HTTP authentication.		no
Request	method	HTTP method to use.	GET	no
	body	Request body (e.g., for POST/PUT).		no
	headers	Additional HTTP headers (one per line as key: value).		no
	not_follow_redirects	Do not follow HTTP redirects.	no	no
	force_http2	Force HTTP/2 (including h2c over TCP).	no	no
Virtual Node	vnode	Associates this data collection job with a Virtual Node.		no

via UI

Configure the k8s_apiserver collector from the Netdata web interface:

1. Go to Nodes.
2. Select the node where you want the k8s_apiserver data-collection job to run and click the ⚙ (Configure this node). That node will run the data collection.
3. The Collectors → Jobs view opens by default.
4. In the Search box, type k8s_apiserver (or scroll the list) to locate the k8s_apiserver collector.
5. Click the + next to the k8s_apiserver collector to add a new job.
6. Fill in the job fields, then click Test to verify the configuration and Submit to save.
   • Test validates the provided settings and checks the collector's startup prerequisites. Successful validation does not guarantee that every metric will be available during collection.
   • If it fails, an error message appears with details (for example, connection refused, timeout, or command execution errors), so you can adjust and retest.

via File

The configuration file name for this integration is go.d/k8s_apiserver.conf.

The file format is YAML. Generally, the structure is:

update_every: 1
autodetection_retry: 0
jobs:
  - name: some_name1
  - name: some_name2

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/k8s_apiserver.conf

Examples

In-cluster (default)

Default configuration when running inside a Kubernetes cluster.

jobs:
  - name: local
    url: https://kubernetes.default.svc:443/metrics
    bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
    tls_ca: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt

External access with kubectl proxy

Access API server metrics via kubectl proxy running on localhost.

Config

jobs:
  - name: via-proxy
    url: http://127.0.0.1:8001/metrics

Direct access with token

Direct access to API server with a bearer token.

Config

jobs:
  - name: direct
    url: https://api.example.com:6443/metrics
    bearer_token_file: /path/to/token
    tls_skip_verify: yes

Alerts

The following alerts are available:

Alert name	On metric	Description
Alert name k8s_apiserver_request_errors	On metrick8s_apiserver.requests_by_code	Descriptionhigh rate of API server request errors (5xx responses)
Alert name k8s_apiserver_latency	On metrick8s_apiserver.request_latency	DescriptionAPI server request latency is high

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per Kubernetes API Server instance

These metrics refer to the entire monitored API server instance.

This scope has no labels.

Metrics:

Metric	Description	Dimensions	Unit
k8s_apiserver.requests_total	API Server Request Rate	requests	requests/s
k8s_apiserver.requests_dropped	API Server Dropped Requests	dropped	requests/s
k8s_apiserver.requests_by_verb	API Server Requests By Verb	a dimension per HTTP verb	requests/s
k8s_apiserver.requests_by_code	API Server Requests By Status Code	a dimension per HTTP status code	requests/s
k8s_apiserver.requests_by_resource	API Server Requests By Resource	a dimension per Kubernetes resource	requests/s
k8s_apiserver.request_latency	API Server Request Latency	p50, p90, p99	milliseconds
k8s_apiserver.response_size	API Server Response Size	p50, p90, p99	bytes
k8s_apiserver.inflight_requests	API Server Inflight Requests	mutating, read_only	requests
k8s_apiserver.longrunning_requests	API Server Long-Running Requests	longrunning	requests
k8s_apiserver.rest_client_requests_by_code	REST Client Requests By Status Code	a dimension per HTTP status code	requests/s
k8s_apiserver.rest_client_requests_by_method	REST Client Requests By Method	a dimension per HTTP method	requests/s
k8s_apiserver.rest_client_latency	REST Client Request Latency	p50, p90, p99	milliseconds
k8s_apiserver.admission_step_latency	Admission Step Latency	validate, admit	milliseconds
k8s_apiserver.etcd_object_counts	Objects Stored In Etcd	a dimension per resource type	objects
k8s_apiserver.audit_events	API Server Audit Events	events, rejected	events/s
k8s_apiserver.authentication_requests	API Server Authenticated Requests	authenticated	requests/s
k8s_apiserver.goroutines	Goroutines	goroutines	goroutines
k8s_apiserver.threads	OS Threads	threads	threads
k8s_apiserver.process_memory	Process Memory	resident, virtual	bytes
k8s_apiserver.heap_memory	Go Heap Memory	alloc, inuse, stack	bytes
k8s_apiserver.gc_duration	GC Duration	min, p25, p50, p75, max	seconds
k8s_apiserver.open_fds	Open File Descriptors	open, max	file descriptors
k8s_apiserver.cpu_usage	CPU Usage	cpu	seconds/s

Per workqueue

These metrics refer to controller work queues.

Labels:

Label	Description
controller	Controller name

Metrics:

Metric	Description	Dimensions	Unit
k8s_apiserver.workqueue_depth	Work Queue Depth	depth	items
k8s_apiserver.workqueue_latency	Work Queue Latency	p50, p90, p99	microseconds
k8s_apiserver.workqueue_adds	Work Queue Adds	adds, retries	items/s
k8s_apiserver.workqueue_duration	Work Queue Work Duration	p50, p90, p99	microseconds

Per admission controller

These metrics refer to admission controllers.

Labels:

Label	Description
name	Admission controller name

Metrics:

Metric	Description	Dimensions	Unit
k8s_apiserver.admission_controller_latency	Admission Controller Latency	5ms, 25ms, 100ms, 500ms, 1s, 2.5s, +Inf	events/s

Per admission webhook

These metrics refer to admission webhooks.

Labels:

Label	Description
name	Webhook name

Metrics:

Metric	Description	Dimensions	Unit
k8s_apiserver.admission_webhook_latency	Admission Webhook Latency	5ms, 25ms, 100ms, 500ms, 1s, 2.5s, +Inf	events/s

Troubleshooting

Diagnostics

Debug Mode

Important: Debug mode is not supported for data collection jobs created via the UI using the Dyncfg feature.

To troubleshoot issues with the k8s_apiserver collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

• Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the plugins setting under [directories].

  cd /usr/libexec/netdata/plugins.d/

• Switch to the netdata user.

  sudo -u netdata -s

• Run the go.d.plugin to debug the collector:

  ./go.d.plugin -d -m k8s_apiserver

  To debug a specific job:

  ./go.d.plugin -d -m k8s_apiserver -j jobName

Getting Logs

If you're encountering problems with the k8s_apiserver collector, follow these steps to retrieve logs and identify potential issues:

• Run the command specific to your system (systemd, non-systemd, or Docker container).
• Examine the output for any warnings or error messages that might indicate issues. These messages should provide clues about the root cause of the problem.

System with systemd

Use the following command to view logs generated since the last Netdata service restart:

journalctl _SYSTEMD_INVOCATION_ID="$(systemctl show --value --property=InvocationID netdata)" --namespace=netdata --grep k8s_apiserver

System without systemd

Locate the collector log file, typically at /var/log/netdata/collector.log, and use grep to filter for collector's name:

grep k8s_apiserver /var/log/netdata/collector.log

Note: This method shows logs from all restarts. Focus on the latest entries for troubleshooting current issues.

Docker Container

If your Netdata runs in a Docker container named "netdata" (replace if different), use this command:

docker logs netdata 2>&1 | grep k8s_apiserver

Other Problems

Connection refused

The API server may not be accessible. Check that:

1. The URL is correct
2. Network policies allow access
3. The ServiceAccount has proper RBAC permissions

401 Unauthorized

Authentication failed. Verify:

1. The bearer token file exists and is readable
2. The token is valid and not expired
3. The ServiceAccount has metrics access permissions

Certificate errors

TLS verification failed. Options:

1. Provide the correct CA certificate path in tls_ca
2. Set tls_skip_verify: yes (not recommended for production)