Docker vs PM2: What are the differences?

Docker is a containerization platform, while PM2 is a process manager for Node.js applications. Let's explore the key differences between them.

1. Containerization vs Process Management: Docker is primarily a containerization tool, which means it packages an application and its dependencies into a standardized unit called a container. This allows for easy portability and scalability across different environments. On the other hand, PM2 is a process manager, specifically designed for Node.js applications. It helps manage the execution and monitoring of multiple processes on a single machine.

2. Isolation Level: Docker provides a higher level of isolation compared to PM2. Docker containers are completely isolated from each other, which means they have separate file systems, network interfaces, and process trees. This makes Docker a suitable choice for running applications with different dependencies or versions. PM2, on the other hand, runs processes within the same environment and does not provide the same level of isolation.

3. Resource Utilization: Docker allows for efficient utilization of system resources by sharing the host's kernel with containers. This means that multiple containers can run on the same machine without duplicating the underlying operating system. PM2, on the other hand, runs processes within a single Node.js instance, which may result in a higher resource utilization when compared to Docker.

4. Deployment Flexibility: Docker provides a high level of deployment flexibility, allowing applications to be deployed on any infrastructure that supports Docker. This includes cloud platforms, virtual machines, or bare-metal servers. PM2, on the other hand, is primarily designed for local or single-server deployments and may not offer the same level of flexibility when it comes to deploying on different platforms.

5. Orchestration and Scaling: Docker provides built-in orchestration and scaling capabilities through its orchestration tool Docker Swarm and container orchestration platform Kubernetes. These tools allow for easy management of multi-container deployments and scaling up or down based on demand. PM2, on the other hand, does not offer built-in orchestration features and may require additional tools or configurations for managing large-scale deployments.

6. Development Workflow: Docker provides a more consistent and reproducible development workflow by encapsulating an application and its dependencies into containers. This allows developers to spin up the entire development environment with a single command, making it easier to collaborate and ensure consistency across different development environments. PM2, on the other hand, focuses more on process management during development and may not provide the same level of encapsulation and standardization as Docker.

In summary, Docker is a containerization tool that provides high-level isolation, deployment flexibility, and scalability, making it suitable for running applications in varying environments. PM2, on the other hand, is a process manager specifically designed for Node.js applications, offering process management and monitoring capabilities within a single server environment.