Service Discovery with Consul and Nginx

This project demonstrates a simple service discovery and load balancing setup using Consul and Nginx. It includes:

• Multiple instances of a Go service
• Consul for service discovery and health checks
• Nginx for load balancing

Features

• Service Discovery: Services automatically register with Consul
• Health Checks: Consul monitors service health
• Load Balancing: Nginx distributes traffic to healthy services
• DNS-based Discovery: Nginx uses Consul's DNS interface

How It Works

1. Service Registration:

   • Each service instance registers with Consul
   • Services include health check endpoints
   • Consul monitors service health and down server whenever health check fail

2. Load Balancing:

   • there is consul-template, which listen the consul
   • and dynamically generate the nginx.conf, whenever there is change
   • and restart the reload nginx -> script -> consul-template.hcl
   • Automatically routes to healthy services
   • No manual configuration needed

3. Health Checking:

   • Consul performs health checks
   • Unhealthy services are automatically removed
   • Services are added back when healthy

Configuration

• Consul: Running on port 8500 (UI)
• Nginx: Running on port 80
• Services: Running on ports 8080, 8081, and 8082

Development

• gvm use go1.16
• download consul-template
• go mod tidy
• go mod vendor
• docker-compose up -d
• Main service via nginx: http://localhost
• Consul UI: http://localhost:8500
• run command -> consul-template -config=./nginx/consul-template.hcl -> in background
• stop some server
• and see updated nginx