【Linux】Docker & Singularity

Docker: Docker uses operating system-level virtualization to create containers, which are isolated from each other and from the host system. Each container includes all the necessary dependencies and configurations required to run the application, making it easy to deploy and scale applications in any environment.

Singularity: Singularity is a container platform. It allows you to create and run containers that package up pieces of software in a way that is portable and reproducible. You can build a container using Singularity on your laptop, and then run it on many of the largest HPC clusters in the world, local universities, or company clusters, a single server, in the cloud, or on a workstation down the hall.

Different:

1. Image Building: Docker images can only be built on a Docker daemon running on a host machine, whereas Singularity images can be built from a variety of sources including Docker images, tar files, and even directly from a recipe file.

2. User Privileges: Docker runs containers as the root user, which can be a security risk. In contrast, Singularity can run containers as non-root users, which can be more secure in some cases.

3. Compatibility: Docker images are typically not compatible across different operating systems, whereas Singularity images can be run across different operating systems without modification.

4. Use cases: Docker is commonly used for deploying applications in production environments, while Singularity is often used for scientific and high-performance computing applications, where reproducibility and portability across different HPC environments are critical.

5. Community: Docker has a large and active community, with many pre-built images available on Docker Hub. Singularity has a smaller but growing community, with a focus on scientific computing and HPC(High-Performance Computing) applications. 

Overall, the main difference between Docker and Singularity is that Singularity is designed for scientific and high-performance computing workloads, while Docker is designed for general-purpose containerization.