Docker Swarm vs Nomad: What are the differences?

Docker Swarm vs Nomad

Docker Swarm and Nomad are both container orchestration tools that help manage and automate the deployment, scaling, and management of containers. While they serve a similar purpose, there are key differences between the two tools.

1. Architecture: Docker Swarm follows a swarm-mode architecture, where a swarm manager is responsible for managing and distributing workloads across a cluster of Docker nodes. On the other hand, Nomad follows a client-server architecture, where a Nomad server manages workloads across a cluster of Nomad clients.

2. Supported Container Runtimes: Docker Swarm is tightly integrated with the Docker ecosystem and supports only Docker containers as the runtime environment. In contrast, Nomad supports multiple container runtimes such as Docker, rkt, and even non-containerized workloads like virtual machines.

3. Scheduling Strategy: Docker Swarm uses a declarative scheduling strategy, where the user specifies the desired state of the swarm and Docker Swarm orchestrates the necessary actions to reach that state. Nomad, on the other hand, uses an imperative scheduling strategy, where the user directly schedules tasks and specifies the constraints and requirements for each task.

4. Service Discovery: Docker Swarm integrates with Docker's built-in service discovery mechanism, which allows services to discover and communicate with each other using service names. Nomad, on the other hand, requires external service discovery mechanisms like Consul for service discovery and communication.

5. Ecosystem Integration: Docker Swarm benefits from its tight integration with the Docker ecosystem, allowing seamless integration with other Docker tools and services. Nomad, while being independent of any specific ecosystem, provides a wide range of integrations with different tools and services, making it more flexible in terms of ecosystem choices.

6. Scalability: Docker Swarm is well-suited for small to medium-sized deployments, offering simplicity and ease of use. Nomad, on the other hand, is designed for large-scale and complex deployments, providing more advanced features such as multi-region support, federated clusters, and hierarchical scheduling.

In summary, Docker Swarm provides a simple and tightly integrated orchestration solution specifically for Docker containers, while Nomad offers a more flexible and scalable approach with support for multiple container runtimes and a wide range of integrations.