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Consul

Introduction​

This cheat sheet provides a quick reference for some common HashiCorp Consul commands and concepts. HashiCorp Consul is an open-source service mesh and service discovery tool for orchestrating and managing microservices.

Installation​

To use HashiCorp Consul, you need to install and configure it on your system or use the cloud-managed version offered by HashiCorp. Refer to the official Consul documentation for installation instructions.

Consul Concepts​

Service Discovery​

Consul provides service discovery capabilities, allowing services to find and communicate with each other dynamically.

  • Register a service with Consul:

    consul agent -dev -node=server-1 -bind=127.0.0.1 -service=web -address=192.168.1.100 -port=80

  • Discover services using DNS or HTTP API.

Key-Value Store​

Consul includes a distributed key-value store for storing configuration data and other key-value pairs.

  • Store a key-value pair in Consul:

    consul kv put path/to/key value

  • Retrieve a value from the key-value store:

    consul kv get path/to/key

Health Checks​

Consul performs health checks on registered services to ensure they are running correctly.

  • Register a health check for a service:

    consul agent -dev -service=web -check=HTTP://localhost:80/health

  • Configure various types of health checks.

Consul CLI​

Consul provides a command-line interface (CLI) for interacting with the Consul cluster.

  • Join a Consul agent to a cluster:

    consul agent -dev -join=consul-server

  • List registered services:

    consul catalog services

Service Mesh​

Consul can be used as a service mesh to handle service-to-service communication, traffic management, and security features.

  • Set up service mesh intentions and routing configurations.

Consul UI​

Consul includes a web-based user interface (UI) for monitoring and managing the Consul cluster.

  • Access the Consul UI at http://localhost:8500 (default port).

ACLs (Access Control Lists)​

Consul supports ACLs to control access to Consul's features and resources.

  • Configure ACLs to restrict access to specific operations.

Consul Command-Line​

  • Start a Consul agent in development mode:

    consul agent -dev

  • Start a Consul server in production mode:

    consul agent -server -bootstrap-expect=1 -data-dir=/tmp/consul

  • Join an existing Consul cluster:

    consul join <address>

  • View the status of the Consul agent:

    consul members

  • Register a service with health checks:

    consul services register service.json

Conclusion​

This cheat sheet covers some common HashiCorp Consul commands and concepts. Consul is a versatile tool for service discovery, key-value storage, and service mesh functionality; refer to the official Consul documentation for more in-depth information and advanced usage.