Application containerization allows microservices and distributed applications to run independently of each other using fewer system resources than virtual machines. Containers virtualize the application environment and allow applications to be updated and redeployed easily. Containers can run within virtual machines, allowing a single physical host to run multiple operating systems and containers that share the same hardware resources. Framework containers are similar to virtual machines but do not provide hardware virtualization - they include the operating system and allow application containers to run on top of them.