Learn in the textbookFundamentals and Types of Virtualization
DefinitionThe container type (コンテナ型) shares the core of one host OS (the kernel) while separating only the application runtime environments (containers).
ExplanationA container has no guest OS; it bundles only the application and the components it needs to run. Because no full OS has to boot, it starts quickly and uses less memory and disk space. In exchange, every container relies on the host OS kernel, so it is not suited to running an OS with a different kernel inside.
AnalogyIt is like a shared office where all tenants share the reception desk and utilities, and each company has only its own partitioned booth.
Memory hookA shipping container moves its contents from carrier to carrier as one box. A software container likewise packs an application and the parts it needs into one box to carry around.