What's the difference between a docker container and a virtual machine?

Docker has the characteristics of small size, rapid migration and deployment, and high efficiency, but the isolation is worse than server virtualization: different containers belong to different waybills (different application instances run on Docker) and are independent of each other (isolated). But it is managed by the same librarian (the kernel of the host operating system), so the librarian can see the relevant information of all containers (because * * * enjoys the kernel of the operating system, the relevant information will be shared by * * *). Server virtualization is like building several independent "docks" on the dock (physical host and virtualization layer)-warehouses (virtual machines). It has completely independent (isolated) space and belongs to different customers (virtual machine owners). Each warehouse has its own librarian (the operating system kernel of the current virtual machine), so other warehouses cannot be managed. There is no information sharing. Therefore, we need to use Docker technology or server virtualization technology in different ways according to different application scenarios and requirements. For example, a typical application scenario of Docker is that when the Docker instance on the host belongs to a single user, it can give full play to the technical advantages of Docker while ensuring security.