Dallay Agents Skills Kubernetes Orchestration

When to Use

• Deploying containerized applications to Kubernetes clusters.
• Writing or reviewing Deployment, Service, Ingress, or other K8s manifests.
• Configuring health probes, resource limits, autoscaling, or rolling updates.
• Troubleshooting pod scheduling, networking, or configuration issues.
• Setting up Kustomize overlays for multi-environment deployments.

Critical Patterns

• Resource Limits Are Mandatory: ALWAYS set both requests and limits for CPU and memory. Without them, a single pod can starve the entire node.
• Health Probes on Every Workload: ALWAYS define readinessProbe and livenessProbe. Without readiness probes, traffic routes to unready pods. Without liveness probes, stuck containers are never restarted.
• Startup Probes for Slow Init: Use startupProbe for applications with long initialization ( JVM, large model loading) to avoid premature liveness kills.
• Never Use latest Tag: Pin image tags to immutable versions or digests. latest causes unpredictable deployments and breaks rollback.
• Namespaces for Isolation: Separate workloads by team, environment, or domain using namespaces. Apply ResourceQuotas per namespace.
• Secrets Are Not Encrypted at Rest by Default: Enable encryption at rest or use external secret managers (Vault, Sealed Secrets, External Secrets Operator).
• Pod Disruption Budgets: Always set PDBs for production workloads to prevent all replicas from being evicted during node maintenance.

Code Examples

Pod Spec with Complete Health Probes

apiVersion: v1
kind: Pod
metadata:
  name: api-server
  labels:
    app: api-server
    version: v1.2.0
spec:
  containers:
    - name: api
      image: myregistry/api-server:1.2.0
      ports:
        - containerPort: 8080
          protocol: TCP
      resources:
        requests:
          cpu: 100m
          memory: 128Mi
        limits:
          cpu: 500m
          memory: 512Mi
      startupProbe:
        httpGet:
          path: /healthz
          port: 8080
        failureThreshold: 30
        periodSeconds: 10
      readinessProbe:
        httpGet:
          path: /ready
          port: 8080
        initialDelaySeconds: 5
        periodSeconds: 10
        timeoutSeconds: 3
        failureThreshold: 3
      livenessProbe:
        httpGet:
          path: /healthz
          port: 8080
        initialDelaySeconds: 15
        periodSeconds: 20
        timeoutSeconds: 5
        failureThreshold: 3
      env:
        - name: DATABASE_URL
          valueFrom:
            secretKeyRef:
              name: db-credentials
              key: url
        - name: LOG_LEVEL
          valueFrom:
            configMapKeyRef:
              name: app-config
              key: log-level
  restartPolicy: Always

Production Deployment with Rolling Updates

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-server
  namespace: production
  labels:
    app: api-server
spec:
  replicas: 3
  revisionHistoryLimit: 5
  selector:
    matchLabels:
      app: api-server
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  template:
    metadata:
      labels:
        app: api-server
        version: v1.2.0
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: api
          image: myregistry/api-server:1.2.0
          ports:
            - containerPort: 8080
          resources:
            requests:
              cpu: 200m
              memory: 256Mi
            limits:
              cpu: "1"
              memory: 1Gi
          readinessProbe:
            httpGet:
              path: /ready
              port: 8080
            periodSeconds: 5
          livenessProbe:
            httpGet:
              path: /healthz
              port: 8080
            periodSeconds: 15
---
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  name: api-server-pdb
  namespace: production
spec:
  minAvailable: 2
  selector:
    matchLabels:
      app: api-server

Services: ClusterIP, NodePort, and LoadBalancer

# Internal service (default ClusterIP)
apiVersion: v1
kind: Service
metadata:
  name: api-server
  namespace: production
spec:
  selector:
    app: api-server
  ports:
    - port: 80
      targetPort: 8080
      protocol: TCP
---
# External access via LoadBalancer
apiVersion: v1
kind: Service
metadata:
  name: api-server-public
  namespace: production
spec:
  type: LoadBalancer
  selector:
    app: api-server
  ports:
    - port: 443
      targetPort: 8080
      protocol: TCP

ConfigMaps and Secrets

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
  namespace: production
data:
  log-level: "info"
  max-connections: "100"
  feature-flags.json: |
    {
      "new-dashboard": true,
      "beta-api": false
    }
---
apiVersion: v1
kind: Secret
metadata:
  name: db-credentials
  namespace: production
type: Opaque
stringData:
  url: "postgres://user:pass@db-host:5432/mydb"
  api-key: "sk-secret-value"

Ingress with TLS

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: api-ingress
  namespace: production
  annotations:
    nginx.ingress.kubernetes.io/rate-limit: "100"
    cert-manager.io/cluster-issuer: letsencrypt-prod
spec:
  ingressClassName: nginx
  tls:
    - hosts:
        - api.example.com
      secretName: api-tls-cert
  rules:
    - host: api.example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: api-server
                port:
                  number: 80

Horizontal Pod Autoscaler

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: api-server-hpa
  namespace: production
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: api-server
  minReplicas: 3
  maxReplicas: 20
  metrics:
    - type: Resource
      resource:
        name: cpu
        target:
          type: Utilization
          averageUtilization: 70
    - type: Resource
      resource:
        name: memory
        target:
          type: Utilization
          averageUtilization: 80
  behavior:
    scaleDown:
      stabilizationWindowSeconds: 300
      policies:
        - type: Percent
          value: 25
          periodSeconds: 60
    scaleUp:
      stabilizationWindowSeconds: 30
      policies:
        - type: Pods
          value: 4
          periodSeconds: 60

Kustomize Base and Overlay

# base/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - deployment.yaml
  - service.yaml
  - ingress.yaml
commonLabels:
  app.kubernetes.io/managed-by: kustomize

# overlays/production/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - ../../base
namespace: production
patches:
  - target:
      kind: Deployment
      name: api-server
    patch: |
      - op: replace
        path: /spec/replicas
        value: 5
      - op: replace
        path: /spec/template/spec/containers/0/resources/limits/memory
        value: 2Gi

Commands

# Apply manifests
kubectl apply -f manifests/ --namespace=production
kubectl apply -k overlays/production/   # Kustomize

# Deployment management
kubectl rollout status deployment/api-server -n production
kubectl rollout history deployment/api-server -n production
kubectl rollout undo deployment/api-server -n production          # rollback one revision
kubectl rollout undo deployment/api-server --to-revision=3 -n production

# Debugging
kubectl get pods -n production -l app=api-server -o wide
kubectl describe pod <pod-name> -n production
kubectl logs <pod-name> -n production --tail=100 -f
kubectl logs <pod-name> -n production -c <container> --previous   # crashed container

# Resource inspection
kubectl top pods -n production
kubectl get events -n production --sort-by='.lastTimestamp'
kubectl get hpa -n production

# Quick exec into a pod
kubectl exec -it <pod-name> -n production -- /bin/sh

# Dry run and diff before applying
kubectl apply -f deployment.yaml --dry-run=server
kubectl diff -f deployment.yaml

Best Practices

DO

• Set requests AND limits on every container.
• Use readinessProbe + livenessProbe on every workload.
• Pin image tags to immutable versions (v1.2.0, not latest).
• Use Namespaces + ResourceQuotas to isolate teams and environments.
• Set terminationGracePeriodSeconds to allow clean shutdown.
• Use PodDisruptionBudget for production Deployments.
• Use kubectl diff and --dry-run=server before applying changes.
• Store manifests in version control and deploy via CI/CD.
• Use Kustomize or Helm for environment-specific configuration.
• Set revisionHistoryLimit on Deployments to control rollback depth.

DON'T

• Run containers as root — use securityContext.runAsNonRoot: true.
• Store secrets in plain ConfigMaps — use Secret resources or external managers.
• Use kubectl apply directly in production without review — use GitOps or CI/CD.
• Set maxUnavailable to 100% in rolling updates — guarantees downtime.
• Omit resource requests — causes unpredictable scheduling and node pressure.
• Use hostNetwork: true or hostPort unless absolutely required.
• Hardcode environment values — use ConfigMaps, Secrets, or Kustomize overlays.
• Ignore pod eviction signals — handle SIGTERM gracefully in your application.

Source: dallay/agents-skills — distributed by TomeVault.