Virtual Machines vs. Containers

vm_vs_container.MD

Virtual Machines vs. Containers

Virtualization Level

Virtual Machines (VMs)

• Utilize hardware virtualization.
• Rely on a hypervisor to virtualize physical hardware resources (processors, RAM, storage, network cards).

Containers

• Use operating system-level virtualization.
• Built upon the host OS's kernel, allowing multiple containers to run on a single OS instance.

Isolation

VMs

• Achieve machine isolation, creating independent virtual machines with a hypervisor.

Containers

• Provide process isolation, enabling applications to run in separate environments with only necessary resources visible.

Resource Access

VMs

• Interaction mainly through a Type 1 hypervisor, simulating hardware.

Containers

• Utilize Linux kernel features like namespaces (for isolated environments) and cgroups (for resource monitoring and limitation).

Portability and Flexibility

VMs

• Offer flexibility in configuring virtual hardware.

Containers

• Provide portability, defined by a Docker file or similar, easily deployable across different environments.

Type 2 Virtualization

• Operates above the hardware level, commonly seen in tools like VirtualBox or Parallels.
• Integration of VMs and containers (e.g., KubeVirt in Kubernetes and OpenShift) can address various use-cases.

Conclusion

VMs and containers, while distinct in their operation and purposes, are increasingly used together in cloud-native application development and deployment, offering a blend of isolation, flexibility, and portability.