Consul: Service Discovery & Configuration
Master HashiCorp Consul for service discovery, configuration management, and service mesh
20 min read•Intermediate
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What is Consul?
HashiCorp Consul is a service networking solution that enables teams to manage secure network connectivity between services, discover services dynamically, and configure services centrally. It provides service discovery, health checking, key-value storage, and multi-datacenter support out of the box.
Core Components
- • Service Registry & Discovery
- • Health Monitoring
- • KV Store
- • Service Mesh (Connect)
- • Multi-Datacenter
Key Benefits
- • Dynamic infrastructure
- • Zero-trust security
- • Runtime configuration
- • Platform agnostic
- • High availability
Core Features
Service Discovery
Automatic service registration and discovery with health checking
Use Case: Microservices can find and communicate with each other dynamically
Configuration Example
{
"service": {
"name": "api-gateway",
"port": 8080,
"tags": ["primary", "v1"],
"check": {
"http": "http://localhost:8080/health",
"interval": "10s",
"timeout": "5s"
}
}
}
Key Benefits
✓Dynamic service registry
✓Health-based routing
✓DNS and HTTP interfaces
✓Multi-datacenter support
✓Service mesh integration
Service Health Monitor
Cluster Health Status
Overall Health: 75%
Healthy Services
3Warning Services
1Critical Services
0Health Check Types
•
HTTP
REST endpoint checks
•
TCP
Port connectivity
•
Script
Custom health scripts
Implementation Patterns
Service Mesh with Consul Connect
Zero-trust networking with automatic TLS and service authorization
Implementation: Sidecar proxies handle encryption and authorization
Example Configuration
# Service definition with Connect
{
"service": {
"name": "web",
"port": 8080,
"connect": {
"sidecar_service": {
"proxy": {
"upstreams": [
{
"destination_name": "api",
"local_bind_port": 9090
}
]
}
}
}
}
}
# Intention for service authorization
consul intention create -allow web api
Key Considerations
- →Automatic mTLS between services
- →Service-to-service authorization
- →Transparent proxy injection
- →Observability integration
- →Progressive rollout support
Consul vs Other Solutions
Feature | Consul | Eureka | Etcd | Zookeeper |
---|---|---|---|---|
Service Discovery | ✓ Native | ✓ Native | ○ Basic | ○ Basic |
Health Checking | ✓ Built-in | ✓ Built-in | ✗ External | ✗ External |
KV Store | ✓ Yes | ✗ No | ✓ Yes | ✓ Yes |
Multi-DC | ✓ Native | ○ Limited | ○ Manual | ○ Manual |
Service Mesh | ✓ Connect | ✗ No | ✗ No | ✗ No |
Best Practices
Deployment
- •Run 3-5 server nodes for HA
- •Use separate server and client agents
- •Enable ACLs in production
- •Use TLS for agent communication
Performance
- •Tune health check intervals
- •Use blocking queries for watches
- •Cache DNS responses appropriately
- •Limit KV value sizes (< 512KB)
Security
- •Enable and enforce ACLs
- •Use intentions for service auth
- •Rotate gossip encryption keys
- •Audit sensitive KV operations
Monitoring
- •Export metrics to Prometheus
- •Monitor leader elections
- •Track service health trends
- •Alert on cluster state changes
📝 Test Your Knowledge
📝 Consul Quiz
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