Summary
HashiCorp Consul is a distributed service networking platform that combines service discovery, health checking, a key-value store, and a service mesh to connect and secure services across any infrastructure.
What is Consul?
Consul agents run on each node in the infrastructure and form a distributed cluster. Services register themselves with their local agent, which propagates the information cluster-wide. Clients discover services by querying Consul's DNS interface or HTTP API, getting back healthy instances only.
Consul Connect adds a service mesh layer: it can automatically provision mutual TLS certificates between services and enforce traffic policies using Envoy proxy sidecars, without application code changes. Intentions define which services are allowed to communicate.
The key-value store provides distributed configuration storage used by many tools in the HashiCorp stack and third-party applications. Consul's health checking monitors services and removes failed instances from discovery results automatically.
Why is Consul relevant?
- Service discovery: Replaces hard-coded endpoints with dynamic, health-checked lookups
- Zero-trust networking: Mutual TLS between services without code changes
- Multi-platform: Works across VMs, containers, Kubernetes, and bare metal simultaneously
- Ecosystem integration: Native integration with Terraform, Vault, and Nomad