feat: add lightweight Alpine Unbound DNS container

- Multi-arch support (x86_64 and ARM64)
- ~50MB image size vs ~500MB for Ubuntu version
- DNSSEC validation with root hints
- Health checks and resource limits
- Security hardening (hide identity/version, harden-glue, etc.)
- Build script for easy single/multi-arch builds

builds/alpine-unbound/Dockerfile

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+# Alpine Unbound DNS Server - Lightweight Edition
+# Multi-architecture support: amd64, arm64, arm/v7
+FROM alpine:3.19
+
+LABEL maintainer="homelab"
+LABEL description="Lightweight Unbound DNS resolver"
+
+# Set timezone (can be overridden at runtime)
+ENV TZ=UTC
+
+# Install only essential packages for Unbound DNS
+RUN apk add --no-cache \
+    # Core DNS
+    unbound \
+    # DNS utilities for debugging
+    drill \
+    bind-tools \
+    # Basic networking tools
+    curl \
+    ca-certificates \
+    # Timezone data
+    tzdata \
+    # Process management (lightweight alternative to supervisor)
+    tini \
+    && rm -rf /var/cache/apk/*
+
+# Create necessary directories
+RUN mkdir -p /etc/unbound/unbound.conf.d \
+    /var/lib/unbound \
+    /var/log/unbound \
+    /config
+
+# Download root hints for DNSSEC validation
+RUN curl -sSL https://www.internic.net/domain/named.root -o /etc/unbound/root.hints
+
+# Set proper permissions
+RUN chown -R unbound:unbound /var/lib/unbound /var/log/unbound
+
+# Copy default configuration
+COPY unbound.conf /etc/unbound/unbound.conf
+
+# Create healthcheck script
+RUN echo '#!/bin/sh' > /usr/local/bin/healthcheck.sh && \
+    echo 'drill @127.0.0.1 -p 5335 google.com > /dev/null 2>&1' >> /usr/local/bin/healthcheck.sh && \
+    chmod +x /usr/local/bin/healthcheck.sh
+
+# Expose DNS port
+EXPOSE 5335/tcp 5335/udp
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD /usr/local/bin/healthcheck.sh
+
+# Use tini as init system for proper signal handling
+ENTRYPOINT ["/sbin/tini", "--"]
+
+# Run unbound in foreground
+CMD ["unbound", "-d", "-c", "/etc/unbound/unbound.conf"]

builds/alpine-unbound/Dockerfile.amd64

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+# Alpine Unbound DNS Server - x86_64/AMD64 Edition
+FROM --platform=linux/amd64 alpine:3.19
+
+LABEL maintainer="homelab"
+LABEL description="Lightweight Unbound DNS resolver for x86_64"
+LABEL architecture="amd64"
+
+# Set timezone (can be overridden at runtime)
+ENV TZ=UTC
+
+# Install only essential packages for Unbound DNS
+RUN apk add --no-cache \
+    # Core DNS
+    unbound \
+    # DNS utilities for debugging
+    drill \
+    bind-tools \
+    # Basic networking tools
+    curl \
+    ca-certificates \
+    # Timezone data
+    tzdata \
+    # Process management (lightweight alternative to supervisor)
+    tini \
+    && rm -rf /var/cache/apk/*
+
+# Create necessary directories
+RUN mkdir -p /etc/unbound/unbound.conf.d \
+    /var/lib/unbound \
+    /var/log/unbound \
+    /config
+
+# Download root hints for DNSSEC validation
+RUN curl -sSL https://www.internic.net/domain/named.root -o /etc/unbound/root.hints
+
+# Set proper permissions
+RUN chown -R unbound:unbound /var/lib/unbound /var/log/unbound
+
+# Copy default configuration
+COPY unbound.conf /etc/unbound/unbound.conf
+
+# Create healthcheck script
+RUN echo '#!/bin/sh' > /usr/local/bin/healthcheck.sh && \
+    echo 'drill @127.0.0.1 -p 5335 google.com > /dev/null 2>&1' >> /usr/local/bin/healthcheck.sh && \
+    chmod +x /usr/local/bin/healthcheck.sh
+
+# Expose DNS port
+EXPOSE 5335/tcp 5335/udp
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD /usr/local/bin/healthcheck.sh
+
+# Use tini as init system for proper signal handling
+ENTRYPOINT ["/sbin/tini", "--"]
+
+# Run unbound in foreground
+CMD ["unbound", "-d", "-c", "/etc/unbound/unbound.conf"]

builds/alpine-unbound/Dockerfile.arm64

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+# Alpine Unbound DNS Server - ARM64/aarch64 Edition
+FROM --platform=linux/arm64 alpine:3.19
+
+LABEL maintainer="homelab"
+LABEL description="Lightweight Unbound DNS resolver for ARM64"
+LABEL architecture="arm64"
+
+# Set timezone (can be overridden at runtime)
+ENV TZ=UTC
+
+# Install only essential packages for Unbound DNS
+RUN apk add --no-cache \
+    # Core DNS
+    unbound \
+    # DNS utilities for debugging
+    drill \
+    bind-tools \
+    # Basic networking tools
+    curl \
+    ca-certificates \
+    # Timezone data
+    tzdata \
+    # Process management (lightweight alternative to supervisor)
+    tini \
+    && rm -rf /var/cache/apk/*
+
+# Create necessary directories
+RUN mkdir -p /etc/unbound/unbound.conf.d \
+    /var/lib/unbound \
+    /var/log/unbound \
+    /config
+
+# Download root hints for DNSSEC validation
+RUN curl -sSL https://www.internic.net/domain/named.root -o /etc/unbound/root.hints
+
+# Set proper permissions
+RUN chown -R unbound:unbound /var/lib/unbound /var/log/unbound
+
+# Copy default configuration
+COPY unbound.conf /etc/unbound/unbound.conf
+
+# Create healthcheck script
+RUN echo '#!/bin/sh' > /usr/local/bin/healthcheck.sh && \
+    echo 'drill @127.0.0.1 -p 5335 google.com > /dev/null 2>&1' >> /usr/local/bin/healthcheck.sh && \
+    chmod +x /usr/local/bin/healthcheck.sh
+
+# Expose DNS port
+EXPOSE 5335/tcp 5335/udp
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD /usr/local/bin/healthcheck.sh
+
+# Use tini as init system for proper signal handling
+ENTRYPOINT ["/sbin/tini", "--"]
+
+# Run unbound in foreground
+CMD ["unbound", "-d", "-c", "/etc/unbound/unbound.conf"]

builds/alpine-unbound/README.md

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+# Alpine Unbound DNS Server
+
+A lightweight Alpine-based Unbound DNS resolver container, optimized for homelab use.
+
+## Features
+
+- 🪶 **Lightweight**: ~50MB image size (vs ~500MB+ for Ubuntu-based)
+- 🔒 **DNSSEC Validation**: Full DNSSEC support with automatic root trust anchor updates
+- 🏗️ **Multi-Architecture**: Native support for x86_64 and ARM64 (Raspberry Pi, Apple Silicon)
+- ❤️ **Health Checks**: Built-in health monitoring
+- 🔧 **Hardened Config**: Security best practices out of the box
+- 📊 **Resource Efficient**: Memory limits of 128MB (typically uses ~30-50MB)
+
+## Quick Start
+
+### Using Docker Compose
+
+```bash
+docker-compose up -d
+```
+
+### Building Manually
+
+```bash
+# For x86_64/AMD64
+docker build -f Dockerfile.amd64 -t alpine-unbound:amd64 .
+
+# For ARM64 (Raspberry Pi 4/5, Apple Silicon)
+docker build -f Dockerfile.arm64 -t alpine-unbound:arm64 .
+
+# Multi-arch build (if using buildx)
+./build.sh multiarch
+```
+
+## Architecture-Specific Dockerfiles
+
+| File | Architecture | Use Case |
+|------|-------------|----------|
+| `Dockerfile` | Auto-detect | General use, multi-arch builds |
+| `Dockerfile.amd64` | x86_64 | Intel/AMD servers, desktop PCs |
+| `Dockerfile.arm64` | ARM64 | Raspberry Pi 4/5, Apple Silicon, AWS Graviton |
+
+## Configuration
+
+The default configuration (`unbound.conf`) includes:
+
+- Listening on port **5335** (to avoid conflicts with other DNS services)
+- Access allowed from all RFC1918 private networks
+- DNSSEC validation enabled
+- Query name minimization for privacy
+- Aggressive caching for performance
+- Security hardening options
+
+### Custom Configuration
+
+Mount your own config files:
+
+```yaml
+volumes:
+  - ./my-unbound.conf:/etc/unbound/unbound.conf:ro
+  - ./conf.d/:/etc/unbound/unbound.conf.d/:ro
+```
+
+## Integration with Pi-hole
+
+Use as upstream DNS for Pi-hole:
+
+```yaml
+# In Pi-hole's docker-compose.yml
+environment:
+  - PIHOLE_DNS_=172.17.0.1#5335
+```
+
+## Comparison with Ubuntu Version
+
+| Aspect | Alpine | Ubuntu |
+|--------|--------|--------|
+| Image Size | ~50MB | ~500MB+ |
+| Memory Usage | ~30-50MB | ~100-200MB |
+| SSH Access | ❌ | ✅ |
+| Dev Tools | ❌ | ✅ |
+| Shell | ash | zsh (oh-my-zsh) |
+| Init System | tini | supervisord |
+| Startup Time | <1s | ~5s |
+
+Choose **Alpine** for: Production DNS, resource-constrained devices, simple deployments.
+
+Choose **Ubuntu** for: Development, debugging, when you need SSH access or interactive shell.
+
+## Ports
+
+| Port | Protocol | Description |
+|------|----------|-------------|
+| 5335 | TCP/UDP | Unbound DNS |
+
+## Environment Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `TZ` | `UTC` | Timezone |
+
+## Health Check
+
+The container includes automatic health checks using `drill`:
+
+```bash
+drill @127.0.0.1 -p 5335 google.com
+```
+
+## Troubleshooting
+
+### Check if Unbound is running
+```bash
+docker exec alpine_unbound drill @127.0.0.1 -p 5335 google.com
+```
+
+### View logs
+```bash
+docker logs alpine_unbound
+```
+
+### Test DNSSEC validation
+```bash
+docker exec alpine_unbound drill -D sigok.verteiltesysteme.net @127.0.0.1 -p 5335
+```
+
+## License
+
+MIT

builds/alpine-unbound/build.sh

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+#!/bin/bash
+# Build script for Alpine Unbound DNS containers
+# Supports building for multiple architectures
+
+set -e
+
+IMAGE_NAME="${IMAGE_NAME:-alpine-unbound}"
+REGISTRY="${REGISTRY:-}"
+VERSION="${VERSION:-latest}"
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+print_status() {
+    echo -e "${GREEN}[INFO]${NC} $1"
+}
+
+print_warning() {
+    echo -e "${YELLOW}[WARN]${NC} $1"
+}
+
+print_error() {
+    echo -e "${RED}[ERROR]${NC} $1"
+}
+
+# Build for specific architecture
+build_single() {
+    local arch=$1
+    local dockerfile="Dockerfile.${arch}"
+    local tag="${IMAGE_NAME}:${VERSION}-${arch}"
+    
+    if [[ -n "$REGISTRY" ]]; then
+        tag="${REGISTRY}/${tag}"
+    fi
+    
+    print_status "Building for ${arch}..."
+    docker build -f "$dockerfile" -t "$tag" .
+    print_status "Successfully built: $tag"
+}
+
+# Build multi-arch image using buildx
+build_multiarch() {
+    local tag="${IMAGE_NAME}:${VERSION}"
+    
+    if [[ -n "$REGISTRY" ]]; then
+        tag="${REGISTRY}/${tag}"
+    fi
+    
+    print_status "Building multi-architecture image..."
+    
+    # Check if buildx is available
+    if ! docker buildx version &>/dev/null; then
+        print_error "Docker buildx is not available. Please install it first."
+        exit 1
+    fi
+    
+    # Create builder if not exists
+    if ! docker buildx inspect multiarch-builder &>/dev/null; then
+        print_status "Creating buildx builder..."
+        docker buildx create --name multiarch-builder --driver docker-container --use
+    else
+        docker buildx use multiarch-builder
+    fi
+    
+    # Build and push (or load for local use)
+    if [[ -n "$REGISTRY" ]] && [[ "$PUSH" == "true" ]]; then
+        docker buildx build \
+            --platform linux/amd64,linux/arm64 \
+            -t "$tag" \
+            --push \
+            .
+    else
+        print_warning "Building for local use only. Use PUSH=true REGISTRY=your-registry to push."
+        docker buildx build \
+            --platform linux/amd64,linux/arm64 \
+            -t "$tag" \
+            --load \
+            .
+    fi
+    
+    print_status "Successfully built: $tag"
+}
+
+# Show help
+show_help() {
+    echo "Usage: $0 [COMMAND] [OPTIONS]"
+    echo ""
+    echo "Commands:"
+    echo "  amd64       Build for x86_64/AMD64 architecture"
+    echo "  arm64       Build for ARM64/aarch64 architecture"
+    echo "  multiarch   Build for all architectures (requires buildx)"
+    echo "  all         Build separate images for each architecture"
+    echo "  help        Show this help message"
+    echo ""
+    echo "Environment variables:"
+    echo "  IMAGE_NAME  Image name (default: alpine-unbound)"
+    echo "  VERSION     Image version tag (default: latest)"
+    echo "  REGISTRY    Docker registry to use (optional)"
+    echo "  PUSH        Set to 'true' to push multiarch images"
+    echo ""
+    echo "Examples:"
+    echo "  $0 amd64                           # Build for x86_64"
+    echo "  $0 arm64                           # Build for ARM64"
+    echo "  $0 all                             # Build for all architectures"
+    echo "  REGISTRY=ghcr.io/user PUSH=true $0 multiarch  # Build and push multiarch"
+}
+
+# Main
+case "${1:-help}" in
+    amd64)
+        build_single "amd64"
+        ;;
+    arm64)
+        build_single "arm64"
+        ;;
+    multiarch)
+        build_multiarch
+        ;;
+    all)
+        build_single "amd64"
+        build_single "arm64"
+        ;;
+    help|--help|-h)
+        show_help
+        ;;
+    *)
+        print_error "Unknown command: $1"
+        show_help
+        exit 1
+        ;;
+esac

builds/alpine-unbound/docker-compose.yml

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+version: "3.9"
+
+services:
+  alpine-unbound:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    image: alpine-unbound:latest
+    container_name: alpine_unbound
+    restart: unless-stopped
+    environment:
+      - TZ=America/New_York
+    volumes:
+      - unbound_config:/etc/unbound/unbound.conf.d
+      - unbound_data:/var/lib/unbound
+    ports:
+      - "5335:5335/tcp"
+      - "5335:5335/udp"
+    networks:
+      - dns_net
+    healthcheck:
+      test: [ "CMD", "/usr/local/bin/healthcheck.sh" ]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 5s
+    deploy:
+      resources:
+        limits:
+          memory: 128M
+        reservations:
+          memory: 32M
+
+networks:
+  dns_net:
+    driver: bridge
+
+volumes:
+  unbound_config:
+    driver: local
+  unbound_data:
+    driver: local

builds/alpine-unbound/unbound.conf

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+# Unbound configuration for Alpine container
+# Optimized for recursive DNS resolution with DNSSEC
+
+server:
+    # Basic settings
+    verbosity: 1
+    num-threads: 2
+    
+    # Interface binding
+    interface: 0.0.0.0
+    port: 5335
+    do-ip4: yes
+    do-ip6: yes
+    do-udp: yes
+    do-tcp: yes
+    
+    # Access control - allow all private networks
+    access-control: 127.0.0.0/8 allow
+    access-control: 10.0.0.0/8 allow
+    access-control: 172.16.0.0/12 allow
+    access-control: 192.168.0.0/16 allow
+    access-control: ::1/128 allow
+    access-control: fd00::/8 allow
+    
+    # Root hints for DNSSEC
+    root-hints: /etc/unbound/root.hints
+    
+    # Trust anchor for DNSSEC validation
+    auto-trust-anchor-file: /var/lib/unbound/root.key
+    
+    # Hide identity and version
+    hide-identity: yes
+    hide-version: yes
+    
+    # Harden settings
+    harden-glue: yes
+    harden-dnssec-stripped: yes
+    harden-referral-path: yes
+    use-caps-for-id: yes
+    
+    # Prefetch settings for performance
+    prefetch: yes
+    prefetch-key: yes
+    
+    # Cache settings
+    cache-min-ttl: 3600
+    cache-max-ttl: 86400
+    msg-cache-size: 50m
+    rrset-cache-size: 100m
+    key-cache-size: 50m
+    neg-cache-size: 10m
+    
+    # Privacy settings
+    qname-minimisation: yes
+    aggressive-nsec: yes
+    
+    # Logging
+    logfile: ""
+    log-queries: no
+    log-replies: no
+    log-local-actions: no
+    log-servfail: yes
+    
+    # User/group (Alpine uses 'unbound' user)
+    username: "unbound"
+    directory: "/etc/unbound"
+    chroot: ""
+    
+    # PID file
+    pidfile: "/var/run/unbound.pid"
+
+# Remote control (disabled for security)
+remote-control:
+    control-enable: no