What is a container?

Answer

A container is a lightweight, standalone unit that packages an application together with its dependencies, libraries, and configuration so it runs consistently across environments. Containers share the host operating system kernel and isolate processes using OS features such as namespaces and cgroups, which makes them far smaller and faster to start than virtual machines. They are the standard way to build, ship, and run cloud-native applications. Docker popularized the format, and the Open Container Initiative (OCI) now defines the image and runtime standards.