What is Kubernetes Resource Metrics API?

Question

Accepted Answer

**Resource Metrics** — real-time CPU and memory usage.

```bash
# Pod metrics
kubectl top pods
kubectl top pods -n production
kubectl top pods --sort-by=cpu
kubectl top pods --sort-by=memory
kubectl top pod my-pod --containers
kubectl top pod my-pod -n production --containers

# Node metrics
kubectl top nodes
kubectl top nodes --sort-by=cpu
kubectl top nodes --sort-by=memory

# Raw metrics API
kubectl get --raw "/apis/metrics.k8s.io/v1beta1/pods" | jq
kubectl get --raw "/apis/metrics.k8s.io/v1beta1/nodes" | jq

# Specific pod metrics
kubectl get --raw "/apis/metrics.k8s.io/v1beta1/namespaces/production/pods/my-pod" | jq

# Check metrics-server
kubectl get deployment metrics-server -n kube-system
kubectl logs -n kube-system -l k8s-app=metrics-server

# Check resource requests vs actual
kubectl describe node node-1 | grep -A 10 "Allocated resources"
kubectl describe pod my-pod | grep -A 5 "Requests:\|Limits:"
```

```yaml
# Install metrics-server
apiVersion: v1
kind: Pod
metadata:
  name: metrics-server
  namespace: kube-system
spec:
  containers:
  - name: metrics-server
    image: registry.k8s.io/metrics-server/metrics-server:v0.6.4
    args:
    - --kubelet-insecure-tls
    - --kubelet-preferred-address-types=InternalIP
```

**Metrics Values:**
- CPU: millicores (1000m = 1 core).
- Memory: bytes.

**Tools:**
- metrics-server: core metrics.
- Prometheus: custom metrics.
- Datadog/New Relic: enhanced metrics.

DevOps: What is Kubernetes Resource Metrics API?