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Cluster Health Score Calculator

Generate an overall health score for a Kubernetes cluster from key operational metrics.

About Cluster Health Score Calculator

This score starts at 100 and subtracts weighted penalties for four common cluster distress signals: the proportion of unhealthy nodes (up to 30 points), pending/unschedulable pods (up to 20 points), pod restart churn (up to 25 points), and elevated etcd latency, which signals control-plane stress (up to 25 points). Formula: health = 100 − unhealthy_node_penalty − pending_pod_penalty − restart_penalty − etcd_penalty. Scores map to Healthy (90+), Degraded (75-89), At Risk (50-74) or Critical (<50).

Formula

Cluster health score

health = 100 - (unhealthy_nodes / total_nodes) × 30 - min(20, pending_pods / 10 × 20) - min(25, restarts / 5) - min(25, max(0, (etcd_latency_ms - 10) / 90 × 25))

unhealthy_nodes
Nodes reporting NotReady or pressure
total_nodes
Total cluster nodes
pending_pods
Pods stuck in Pending state
restarts
Pod restart count in the window
etcd_latency_ms
etcd p99 write/consensus latency (ms)

Worked example

With the default values below, Cluster Health Score Calculator returns Cluster Health Score of 85.3. Change any input above and every figure here is recalculated in your browser.

Inputs used

Total Nodesaccepts 1–100,000 nodes
20 nodes
Unhealthy Nodesaccepts 0–100,000 nodes
1 nodes
Pending Podsaccepts 0–1,000,000 pods
3 pods
Pod Restart Countaccepts 0–1,000,000 restarts
15 restarts
etcd Latencyaccepts 0–10,000 ms
25 ms

Results

Cluster Health Score
85.3
Health Status
Degraded
Unhealthy Node Penalty
1.5
Pending Pod Penalty
6.0
Restart Penalty
3.0
etcd Latency Penalty
4.2

Step by step

  1. 1Unhealthy node penalty= 1.5
  2. 2Pending pod penalty= 6.0
  3. 3Restart penalty= 3.0
  4. 4etcd latency penalty= 4.2
  5. 5Cluster health score= 85.3 (Degraded)

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does etcd latency matter for overall cluster health?

etcd is the cluster's source of truth — the API server, scheduler and controllers all depend on fast etcd reads/writes. Elevated etcd latency (often from disk I/O contention or too many watchers) can cascade into slow scheduling, delayed reconciliation, and API timeouts cluster-wide.

What's a normal etcd latency?

Healthy etcd clusters typically see disk write / consensus latency (p99) under 10-25ms; sustained latency above 100ms is a strong signal of disk or network issues and often precedes broader cluster instability.

Why cap the pending-pod penalty at 20 points?

A handful of pending pods is often transient (waiting for a scale-up event) rather than a systemic issue, so the penalty scales linearly but is capped to avoid over-weighting a metric that self-resolves quickly compared to, say, persistent node failures.

Should pod restarts always be treated as bad?

Not always — some restarts are expected (rolling deploys, liveness probe recovery). This metric is best tracked as a rate/trend over a fixed window rather than a cumulative all-time count, so recalibrate the input to your chosen window.

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Cluster Health Score Calculator | Calcrivo