kubernetes-hello.yml

---
# see https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#serviceaccount-v1-core
apiVersion: v1
kind: ServiceAccount
metadata:
  name: kubernetes-hello
---
# see https://kubernetes.io/docs/reference/access-authn-authz/rbac/
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#role-v1-rbac-authorization-k8s-io
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: pod-read
rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["get", "list"]
---
# see https://kubernetes.io/docs/reference/access-authn-authz/rbac/
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#rolebinding-v1-rbac-authorization-k8s-io
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: kubernetes-hello-pod-read
subjects:
  - kind: ServiceAccount
    name: kubernetes-hello
roleRef:
  kind: Role
  name: pod-read
  apiGroup: rbac.authorization.k8s.io
---
# see https://kubernetes.io/docs/concepts/services-networking/ingress/
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#ingress-v1-networking-k8s-io
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: kubernetes-hello
spec:
  rules:
    - host: kubernetes-hello.example.test
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: kubernetes-hello
                port:
                  name: web
---
# see https://kubernetes.io/docs/concepts/services-networking/service/#type-clusterip
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#service-v1-core
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#serviceport-v1-core
apiVersion: v1
kind: Service
metadata:
  name: kubernetes-hello
spec:
  type: ClusterIP
  selector:
    app: kubernetes-hello
  ports:
    - name: web
      port: 80
      protocol: TCP
      targetPort: web
---
# see https://kubernetes.io/docs/concepts/workloads/controllers/deployment/
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#deployment-v1-apps
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#podtemplatespec-v1-core
# see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.31/#container-v1-core
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kubernetes-hello
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kubernetes-hello
  template:
    metadata:
      labels:
        app: kubernetes-hello
    spec:
      serviceAccountName: kubernetes-hello
      enableServiceLinks: false
      containers:
        # see https://github.com/rgl/kubernetes-hello
        - name: kubernetes-hello
          image: zot.zot.svc.cluster.local:5000/ruilopes/kubernetes-hello:v0.0.202408161942
          env:
            # configure the go runtime to honor the k8s memory and cpu resource
            # limits.
            # NB resourceFieldRef will cast the limits to bytes and integer
            #    number of cpus (rounding up to the nearest integer).
            # see https://pkg.go.dev/runtime
            # see https://www.riverphillips.dev/blog/go-cfs/
            # see https://github.com/golang/go/issues/33803
            # see https://github.com/traefik/traefik-helm-chart/pull/1029
            - name: GOMEMLIMIT
              valueFrom:
                resourceFieldRef:
                  resource: limits.memory
            - name: GOMAXPROCS
              valueFrom:
                resourceFieldRef:
                  resource: limits.cpu
            # see https://github.com/kubernetes/kubernetes/blob/master/test/e2e/common/downward_api.go
            - name: POD_UID
              valueFrom:
                fieldRef:
                  fieldPath: metadata.uid
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: web
              containerPort: 8000
          resources:
            requests:
              memory: 20Mi
              cpu: '0.1'
            limits:
              memory: 20Mi
              cpu: '0.1'
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              drop:
                - ALL
            readOnlyRootFilesystem: true
            runAsNonRoot: true
            seccompProfile:
              type: RuntimeDefault
          volumeMounts:
            - name: tokens
              readOnly: true
              mountPath: /var/run/secrets/tokens
      volumes:
        - name: tokens
          projected:
            sources:
              - serviceAccountToken:
                  path: example.com-jwt.txt
                  audience: example.com
                  # NB the kubelet will periodically rotate this token.
                  # NB the token is rotated when its older than 80% of its time
                  #    to live or if the token is older than 24h.
                  # NB in production, set to a higher value (e.g. 3600 (1h)).
                  # NB the minimum allowed value is 600 (10m).
                  # NB this is equivalent of using the TokenRequest API.
                  #    see https://kubernetes.io/docs/reference/kubernetes-api/authentication-resources/token-request-v1/
                  # NB this is equivalent of executing:
                  #       kubectl create token kubernetes-hello --audience example.com --duration 600s
                  #    see https://kubernetes.io/docs/reference/kubectl/generated/kubectl_create/kubectl_create_token/
                  expirationSeconds: 600