Container
A container is a lightweight isolated runtime environment packaging an application with its dependencies, sharing the host kernel without full OS virtualization.
Purpose
Make applications portable and consistent, eliminating environment drift.
Mechanism
Namespaces isolate process/network/mount; cgroups limit CPU/memory/IO. Layered images (union filesystem) make builds and distribution efficient. Faster to start and lighter on resources than VMs. Implemented by Docker/containerd.
Use cases
- Application packaging
- Environment consistency
- Microservice deployment