What is Kubernetes kubelet configuration?

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Accepted Answer

**Kubelet** — node agent that manages Pods.

```yaml
# kubelet configuration
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
address: 0.0.0.0
port: 10250
authentication:
  anonymous:
    enabled: false
  webhook:
    enabled: true
authorization:
  mode: Webhook
cgroupDriver: systemd
clusterDNS:
- 10.96.0.10
clusterDomain: cluster.local
reservedSystemCPUs: "500m"
evictionHard:
  memory.available: "100Mi"
  nodefs.available: "10%"
  imagefs.available: "15%"
evictionSoft:
  memory.available: "200Mi"
  nodefs.available: "15%"
evictionSoftGracePeriod:
  memory.available: "1m30s"
  nodefs.available: "1m30s"
maxPods: 110
podPidsLimit: 4096
containerLogMaxSize: "50Mi"
containerLogMaxFiles: 5
serializeImagePulls: false
rotateCertificates: true
serverTLSBootstrap: true
```

```bash
# Commands
kubectl describe node node-1 | grep -A 20 "Kubelet Configuration"

# Check kubelet status
systemctl status kubelet
journalctl -u kubelet -f

# kubelet logs
journalctl -u kubelet --since "1 hour ago"
journalctl -u kubelet | grep -i "evict"

# Check node conditions
kubectl get nodes -o json | jq '.items[] | {name: .metadata.name, conditions: .status.conditions}'

# Debug kubelet
curl -k https://localhost:10250/pods
curl -k https://localhost:10250/stats/summary
```

**Key Configurations:**
- maxPods: maximum Pods per node.
- evictionHard/Soft: resource thresholds.
- clusterDNS: DNS server IP.
- cgroupDriver: systemd or cgroupfs.

DevOps: What is Kubernetes kubelet configuration?