VM's vs Containers

OS-level virtual machines (e.g. Xen):

• Do not make virtualization completely available at the OS level:

  • Only the OS services are virtual.

  • Host Kernel: Virtualizes its services in isolation from its tenants.

Container

Isolates the execution environment of one or more processes.

To consider:

• Isolation/Visibility: limit what can be seen by the tenants.

• Resource control: limit resource consumption.

• Portability: can reconstruct the same environment in multiple hosts.

Container-based virtualization depends on OS mechanisms to reach application isolation.