metrics-server

metrics-server is a Kubernetes add-on that aggregates resource metrics (CPU/memory) from kubelets and exposes them to the Kubernetes Metrics API (used by Horizontal Pod Autoscaler and kubectl top).

Evaluated Apr 04, 2026 (17d ago)

Homepage ↗ Repo ↗ Monitoring kubernetes metrics autoscaling hpa observability infrastructure

⚙ Agent Friendliness

/ 100

Can an agent use this?

🔒 Security

/ 100

Is it safe for agents?

⚡ Reliability

/ 100

Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality

Documentation

Error Messages

Auth Simplicity

Rate Limits

🔒 Security

TLS Enforcement

Auth Strength

Scope Granularity

Dep. Hygiene

Secret Handling

Security is primarily determined by Kubernetes RBAC and the TLS/auth configuration between metrics-server and kubelets. As a cluster component, it should not expose secrets directly, but misconfiguration (overly broad RBAC or insecure kubelet access) can weaken security.

⚡ Reliability

Uptime/SLA

Version Stability

Breaking Changes

Error Recovery

Best When

You need cluster resource metrics inside Kubernetes and want the standard Kubernetes metrics pipeline.

Avoid When

You need a full observability stack with retention, alerting, and query languages rather than the Metrics API.

Use Cases

• Enable kubectl top for nodes/pods
• Provide metrics to Horizontal Pod Autoscaler (HPA)
• Support custom autoscaling and dashboards that rely on Kubernetes Metrics API

Not For

• Collecting long-term historical metrics/monitoring (that typically requires Prometheus/Grafana or similar)
• Application-level business metrics
• As a standalone metrics backend for external systems

Interface

REST API

GraphQL

gRPC

MCP Server

SDK

Webhooks

Authentication

Methods: Uses Kubernetes API auth (service accounts/RBAC) to read metrics endpoints; kubelet auth/TLS between metrics-server and kubelets depends on cluster configuration.

OAuth: No Scopes: No

No standalone end-user API auth is described here; access is governed by Kubernetes RBAC and kubelet connectivity/TLS settings.

Pricing

Free tier: No

Requires CC: No

Open-source Kubernetes component; pricing depends on infrastructure.

Agent Metadata

Pagination

none

Idempotent

False

Retry Guidance

Not documented

Known Gotchas

⚠ As a Kubernetes add-on, agent interactions depend on cluster setup (RBAC, TLS to kubelets, APIService registration).
⚠ Metrics availability can lag during kubelet/cluster transitions; agents may see empty/temporary metrics if queried too early.
⚠ Configuration flags and permissions (service account, aggregation permissions) often require manual alignment to the cluster environment.

Alternatives

Prometheus + kube-state-metrics + node-exporter (for richer monitoring) OpenTelemetry Collector + exporters (for standardized telemetry) Cloud provider metrics services (managed)

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Scores are editorial opinions as of 2026-04-04.