Container Missing Liveness Probe

Health Probes in Kubernetes

Kubernetes uses health probes to determine whether a container is alive and ready to serve traffic. Without probes, Kubernetes has no way to detect application-level failures — it only knows if the container process is running.

Example Without Probes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-server
  labels:
    app: api
spec:
  replicas: 3
  selector:
    matchLabels:
      app: api
  template:
    metadata:
      labels:
        app: api
    spec:
      securityContext:
        runAsNonRoot: true
      containers:
        - name: api
          image: api-server:3.2.1
          ports:
            - containerPort: 8080
          resources:
            requests:
              cpu: 200m
              memory: 256Mi
            limits:
              cpu: 500m
              memory: 512Mi

What the Validator Flags

• Warning: Container 'api' has no livenessProbe
• Info: Container 'api' has no readinessProbe

Three Types of Probes

Probe	Purpose	What Happens on Failure
livenessProbe	Is the container alive?	Container is restarted
readinessProbe	Can it accept traffic?	Removed from Service endpoints
startupProbe	Has it finished starting?	Other probes are disabled until success

Probe Configuration Example

livenessProbe:
  httpGet:
    path: /healthz
    port: 8080
  initialDelaySeconds: 15
  periodSeconds: 10
  failureThreshold: 3
readinessProbe:
  httpGet:
    path: /ready
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 5
startupProbe:
  httpGet:
    path: /healthz
    port: 8080
  failureThreshold: 30
  periodSeconds: 10

Probe Types

• httpGet: Performs an HTTP GET request
• tcpSocket: Checks if a port is open
• exec: Runs a command inside the container
• grpc: Performs a gRPC health check (k8s 1.27+)