kubesrv

Minimal HTTP server in C for Kubernetes testing.

Features

• Ultra-small image (~26kb for v1.0.0(without shell) & 1MB for v1.1.0(with shell) )
• Fork-based concurrency
• Health checks (/healthz)
• Prometheus metrics (/metrics)
• Configurable via environment variables

Quick Start

# Run locally
docker run -p 8080:80 bansikah/kubesrv:latest

# Deploy to Kubernetes using Manifests
kubectl apply -f k8s/
kubectl port-forward svc/kubesrv-svc 8080:80 -n kubesrv-ns

# Deploy to Kubernetes using Helm
helm install my-kubesrv ./charts/kubesrv
kubectl port-forward svc/my-kubesrv-kubesrv 8080:80

Helm Chart

The project includes a reusable Helm chart located in charts/kubesrv. For detailed information on security features and customization, see the Helm Documentation.

Installation

helm install [RELEASE_NAME] ./charts/kubesrv

Configuration

The following table lists the configurable parameters of the kubesrv chart and their default values.

Parameter	Description	Default
replicaCount	Number of replicas	1
image.repository	Image repository	bansikah/kubesrv
image.tag	Image tag	"" (defaults to chart appVersion)
service.type	Service type	ClusterIP
service.port	Service port	80
config.message	Greeting message	"Hello, Kubernetes from Helm!"
resources.limits.cpu	CPU limit	100m
resources.limits.memory	Memory limit	32Mi

Endpoints

Path	Description
/	HTML dashboard
/healthz	Health check
/info	JSON server info
/metrics	Prometheus metrics
/debug/k8s	Kubernetes debug info
/dns?host=<hostname>	DNS lookup
/tcp?host=<host>&port=<port>	TCP connectivity test

Configuration

Environment Variables

Variable	Default	Description
PORT	80	Listen port
MESSAGE	Hello, Kubernetes!	Greeting message (fallback)
MESSAGE_FILE	-	Full path or filename to read message from

ConfigMap Volume Mount

You can mount any ConfigMap as a volume and specify the file path:

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  greeting.txt: |
    Hello from my custom ConfigMap!
---
apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
      - name: kubesrv
        env:
        - name: MESSAGE_FILE
          value: "/usr/share/kubesrv/greeting.txt"  # Full path
        volumeMounts:
        - name: config
          mountPath: /usr/share/kubesrv
          readOnly: true
      volumes:
      - name: config
        configMap:
          name: my-config

Priority order:

1. File from ${MESSAGE_FILE} (if set)
2. Environment variable MESSAGE
3. Default: "Hello, Kubernetes!"

Downward API

The /debug/k8s endpoint relies on the Kubernetes Downward API to expose pod information as environment variables. You must configure your deployment to pass this information to the container.

apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
      - name: kubesrv
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        - name: POD_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP
        - name: NODE_NAME
          valueFrom:
            fieldRef:
              fieldPath: spec.nodeName
        - name: SERVICE_ACCOUNT
          valueFrom:
            fieldRef:
              fieldPath: spec.serviceAccountName

Build

docker build -t bansikah/kubesrv:latest .

CI/CD

The project includes automated workflows for continuous integration and deployment using GitHub Actions:

• Build and Push: Triggered on tags (e.g., v1.0.0), builds the Docker image and pushes it to the registry.
• Helm CD: Triggered on changes to Helm charts, performs linting, security scanning, and functional testing in a KinD cluster.

See .github/workflows/ for details.

License

GPL-3.0 - See LICENSE