Cosmolet - BareMetal Kubernetes Services BGP Advertiser

Release Version: beta

Cosmolet has been functionally tested and deemed working. Testing at scale is in progress.

Cosmolet is a Kubernetes controller that automatically advertises Kubernetes service IPs via BGP. It runs as a privileged DaemonSet with direct FRR (Free Range Routing) integration to enable bare-metal Kubernetes clusters to announce service IPs to network infrastructure.

🚀 Features

Reference Network Architecture

• Automatic Service Discovery: Monitors all Kubernetes services across the cluster
• BGP Route Advertisement: Integrates with FRR to advertise ClusterIP and LoadBalancer service IPs
• Health-based Routing: Only advertises routes for healthy services with ready endpoints
• Leader Election: Ensures only one instance manages BGP routes while maintaining monitoring on all nodes
• High Availability: DaemonSet deployment with graceful failover
• Comprehensive Monitoring: Prometheus metrics and health checks
• Security Hardened: Minimal privileges with proper RBAC configuration

📋 Prerequisites

• Kubernetes 1.20+ cluster
• FRR (Free Range Routing) installed on nodes
• BGP-capable network infrastructure (switches/routers)
• Cluster admin permissions for installation

Code Flowchart

Build & Release Instructuction

Clone the repository

git clone https://github.com/platformbuilds/cosmolet.git
cd cosmolet

Download dependencies

go mod download

Build the binary

Simple build (dev only)

go build -o ./bin/cosmolet ./cmd/cosmolet

Production Build (Optimized)

#Build with optimizations (same as used in Dockerfile)
CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build \
    -ldflags='-w -s -extldflags "-static"' \
    -a -installsuffix cgo \
    -o ./bin/cosmolet \
    ./cmd/cosmolet

Cross-Platform Compilation

# Linux (default)
CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build \
  -ldflags='-w -s -extldflags "-static"' \
  -a -installsuffix cgo \
  -o ./bin/cosmolet-linux-amd64 \
  ./cmd/cosmolet

# macOS
CGO_ENABLED=0 GOOS=darwin GOARCH=amd64 go build \
  -ldflags='-w -s -extldflags "-static"' \
  -a -installsuffix cgo \
  -o ./bin/cosmolet-linux-darwin-amd64 \
  ./cmd/cosmolet

# Windows
CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build \
  -ldflags='-w -s -extldflags "-static"' \
  -a -installsuffix cgo \
  -o ./bin/cosmolet-windows-amd64 \
  ./cmd/cosmolet

# ARM64 (for ARM-based systems)
CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build \
  -ldflags='-w -s -extldflags "-static"' \
  -a -installsuffix cgo \
  -o ./bin/cosmolet-linux-arm64 \
  ./cmd/cosmolet

Using the Makefile

The project includes a comprehensive Makefile with various build targets:

# Download dependencies
make deps

# Build binary
make build

# Build with all checks (fmt, vet, test)
make check

# Clean build
make clean && make build

Multi-Architecture Build Script

#!/bin/bash
# build-all.sh

platforms=("linux/amd64" "linux/arm64" "darwin/amd64" "windows/amd64")

for platform in "${platforms[@]}"
do
    platform_split=(${platform//\// })
    GOOS=${platform_split[0]}
    GOARCH=${platform_split[1]}
    output_name='./bin/cosmolet-'$GOOS'-'$GOARCH
    if [ $GOOS = "windows" ]; then
        output_name+='.exe'
    fi

    env GOOS=$GOOS GOARCH=$GOARCH CGO_ENABLED=0 go build \
        -ldflags='-w -s' \
        -o bin/$output_name ./cmd/cosmolet
        
    if [ $? -ne 0 ]; then
        echo 'An error has occurred! Aborting the script execution...'
        exit 1
    fi
done

Development Build

# Build with debug info
go build -gcflags="all=-N -l" -o ./bin/cosmolet-debug ./cmd/cosmolet

Build Flags Explanation

• -ldflags='-w -s': Remove debug info and symbol table (reduces binary size)
• -extldflags "-static": Create statically linked binary
• CGO_ENABLED=0: Disable CGO for pure Go binary
• -a: Force rebuilding of packages
• -installsuffix cgo: Use different install suffix for CGO

Environment Variables for Build

# Set common build environment
export CGO_ENABLED=0
export GOOS=linux
export GOARCH=amd64

# Build with environment
go build -ldflags='-w -s' -o cosmolet ./cmd/main.go

Verification

After building, verify the binary:

# Check binary info
file cosmolet
ldd cosmolet  # Should show "not a dynamic executable" for static build

# Test binary
./cosmolet --help
./cosmolet --version

Common Build Issues

• Dependency Issues:

go mod tidy
go mod verify

• CGO Dependencies:

# If you encounter CGO issues, try:
CGO_ENABLED=0 go build ./cmd/main.go

• Module Path Issues:

# Ensure you're in the correct directory
go mod init github.com/platformcosmo/cosmolet  # if starting fresh

The resulting binary will be statically linked and suitable for deployment in containers or bare-metal systems without external dependencies.

🤝 Contributing

We welcome contributions! Please see CONTRIBUTING.md for details.

📄 License

This project is licensed under the GNU Affero General Public License v3.0 - see the LICENSE file for details.

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