Rkt
Rkt (pronounced 'rocket') is a container runtime developed by CoreOS, designed as a secure, composable, and standards-based alternative to Docker. It focuses on security by default, with features like image signing and verification, and integrates with systemd for process management. Rkt emphasizes simplicity and interoperability, supporting the App Container (appc) specification and later OCI (Open Container Initiative) standards.
Developers should learn Rkt when working in environments that prioritize security and compliance, such as financial services or healthcare, due to its built-in security features like image verification and minimal attack surface. It's also useful in production systems that require tight integration with systemd or need a lightweight, composable container runtime for orchestration platforms like Kubernetes. Rkt is particularly valuable for teams adopting container standards and seeking alternatives to Docker's monolithic architecture.