kubernetes-deployer

# Kubernetes Deployer

Deploy applications to Kubernetes with production-ready configurations, starting locally with Minikube.

## Deployment Workflow

```
1. Dockerfile     → Containerize application
2. Helm Chart     → Package Kubernetes manifests
3. Local Deploy   → Test in Minikube
4. Cloud Ready    → Configure for production
```

## Quick Start: Local Deployment

### 1. Create Dockerfile

```dockerfile
# Python example (see references for other languages)
FROM python:3.11-slim AS builder
WORKDIR /build
COPY pyproject.toml ./
RUN pip install --no-cache-dir .

FROM python:3.11-slim
WORKDIR /app
RUN useradd -m -u 1000 appuser
COPY --from=builder /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages
COPY app ./app
USER appuser
EXPOSE 8000
CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]
```

### 2. Copy Helm Chart Template

Copy `assets/helm-template/` to `charts/<app-name>/` and customize:

```bash
cp -r assets/helm-template charts/myapp
# Edit Chart.yaml: name, description
# Edit values.yaml: image, ports, resources
```

### 3. Deploy to Minikube

```bash
# Start Minikube
minikube start

# Build image in Minikube's Docker
eval $(minikube docker-env)
docker build -t myapp:local .

# Deploy with Helm
helm upgrade --install myapp ./charts/myapp \
  --set image.repository=myapp \
  --set image.tag=local \
  --set image.pullPolicy=Never

# Access service
kubectl port-forward svc/myapp 8080:80
```

## Core Principles

1. **Local-first** - Test everything in Minikube before cloud
2. **Stateless services** - No local state; use external databases
3. **Config via env vars** - All configuration through environment
4. **12-factor ready** - Portable between environments

## Helm Chart Structure

```
charts/<app-name>/
├── Chart.yaml        # Metadata
├── values.yaml       # Default config
└── templates/
    ├── _helpers.tpl  # Template functions
    ├── deployment.yaml
    ├── service.yaml
    ├── ingress.yaml  # Optional
    └── hpa.yaml      # Optional
```

## Configuration Patterns

### Environment Variables

```yaml
# values.yaml
env:
  - name: DATABASE_URL
    value: "postgresql://..."
  - name: LOG_LEVEL
    value: "info"

# From secrets
envFrom:
  - secretRef:
      name: app-secrets
```

### Create Secret

```bash
kubectl create secret generic app-secrets \
  --from-literal=DATABASE_PASSWORD=secret123 \
  --from-literal=API_KEY=key456
```

### Health Checks

```yaml
# values.yaml
livenessProbe:
  httpGet:
    path: /health
    port: http
  initialDelaySeconds: 10

readinessProbe:
  httpGet:
    path: /health
    port: http
  initialDelaySeconds: 5
```

## Common Commands

### Minikube

```bash
minikube start                    # Start cluster
minikube dashboard                # Open dashboard
eval $(minikube docker-env)       # Use Minikube Docker
minikube service myapp --url      # Get service URL
```

### Helm

```bash
helm lint ./charts/myapp                    # Validate chart
helm template myapp ./charts/myapp          # Preview manifests
helm upgrade --install myapp ./charts/myapp # Deploy
helm uninstall myapp                        # Remove
```

### Kubectl

```bash
kubectl get pods                  # List pods
kubectl logs <pod>                # View logs
kubectl describe pod <pod>        # Debug pod
kubectl port-forward svc/myapp 8080:80  # Access locally
```

## Environment-Specific Values

```yaml
# values-dev.yaml
replicaCount: 1
resources:
  limits:
    cpu: 200m
    memory: 256Mi

# values-prod.yaml
replicaCount: 3
autoscaling:
  enabled: true
  minReplicas: 3
  maxReplicas: 10
```

Deploy with environment:
```bash
helm upgrade --install myapp ./charts/myapp \
  -f values.yaml \
  -f values-prod.yaml
```

## Troubleshooting

| Issue | Command |
|-------|---------|
| Pod not starting | `kubectl describe pod <name>` |
| Image not found | `minikube ssh docker images` |
| Service unreachable | `kubectl get endpoints` |
| Logs | `kubectl logs <pod> -f` |

## References

- [references/dockerfile-patterns.md](references/dockerfile-patterns.md) - Multi-stage builds, language templates, security
- [references/helm-charts.md](references/helm-charts.md) - Chart structure, templates, values configuration
- [references/minikube-local.md](references/minikube-local.md) - Local images, service access, debugging

## Assets

- [assets/helm-template/](assets/helm-template/) - Ready-to-use Helm chart template