bazel-k8s-expert

bazel-k8s-expert

Keyword: k8s | Platforms: gemini,claude,codex

Bazel Kubernetes Expert Skill - Deploying, managing, and operating Quarkus and Java applications on Kubernetes using Bazel-native tooling.

Core Mandates

• GitOps-Ready: All K8s manifests must be generated from Bazel targets, never hand-edited YAML in production.
• Hermetic Deployments: Use rules_k8s or helm via Bazel to ensure deployment artifacts match built images exactly.
• Health Probes: Every deployment must define @Liveness and @Readiness probes (see microprofile-expert).
• Resource Limits: Always set CPU/memory requests and limits to prevent cluster starvation.
• Config Externalization: Use ConfigMaps and Secrets for environment-specific values; never bake config into images.

---

Setup (Bzlmod)

MODULE.bazel

bazel_dep(name = "rules_k8s", version = "0.7")
bazel_dep(name = "rules_helm", version = "0.1")

# For Kustomize support
bazel_dep(name = "rules_kustomize", version = "0.1")

---

rules_k8s Deployment

Basic Deployment + Service

# services/user/k8s/BUILD.bazel
load("@rules_k8s//k8s:defs.bzl", "k8s_deploy")

k8s_deploy(
    name = "user-service_deploy",
    template = ":deployment.yaml",
    images = {
        "user-service": "//services/user:user-service_image",
    },
)

# services/user/k8s/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
  labels:
    app: user-service
spec:
  replicas: 3
  selector:
    matchLabels:
      app: user-service
  template:
    metadata:
      labels:
        app: user-service
    spec:
      containers:
        - name: user-service
          image: user-service  # Replaced by rules_k8s
          ports:
            - containerPort: 8080
          env:
            - name: QUARKUS_HTTP_PORT
              value: "8080"
            - name: JAVA_TOOL_OPTIONS
              value: "-XX:+UseContainerSupport -XX:MaxRAMPercentage=75.0"
          resources:
            requests:
              memory: "256Mi"
              cpu: "250m"
            limits:
              memory: "512Mi"
              cpu: "500m"
          livenessProbe:
            httpGet:
              path: /q/health/live
              port: 8080
            initialDelaySeconds: 30
            periodSeconds: 10
          readinessProbe:
            httpGet:
              path: /q/health/ready
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
---
apiVersion: v1
kind: Service
metadata:
  name: user-service
spec:
  selector:
    app: user-service
  ports:
    - port: 80
      targetPort: 8080
  type: ClusterIP