What is the Difference Between Container and VM

The main difference between Container and VM is that the container provides OS-level virtualization while the VM, or Virtual Machine, provides hardware-level virtualization.

Virtualization is the process of creating a virtual operating system, a server, a storage device or network resources. Containers and VMs are two virtualization technologies. We can use both of them to increase the flexibility, minimize resource requirements and maximize functionalities.

Key Areas Covered

1. What is VM
     – Definition, Functionality, Features
2. What is Container
     – Definition, Functionality, Features
3. What is the Difference Between Container and VM
     – Comparison of Key Differences

Key Terms

Container, Process Virtual Machine, System Virtual Machine, VM, Virtualization

What is VM

VM refers to a virtual machine. It is an emulation of a computer system. Moreover, a VM is based on computer architecture and provides the functionality of a physical computer. It includes specialized hardware, software or a combination. A hypervisor or a virtual machine monitor is used to create and run VMs.

Figure 1: Virtualization

There are two types of VMs as system virtual machines and process virtual machines. A system virtual machine provides a substitute for a real machine. Furthermore, it provides the functionality required to execute an entire operating system. A process virtual machine, on the other hand, executes computer programs in a platform-independent environment. In addition, many IP departments use VMs as they reduce the cost and improves efficiency.

What is a Container

A container is a software package that consists of everything to run applications. Unlike a VM, which virtualizes the underlying computer, a container virtualizes the OS. It is at the top of a physical server, and its host OS is usually Windows or Linux. Each container shares the host OS kernel, binaries and libraries. Moreover, it is only possible to read the shared components in a container.

Figure 2: Docker Container

Sharing OS resource such as libraries minimizes the necessity to generate the OS code. Therefore, a server can run multiple workloads with a single operating system installation. Moreover, a container is megabytes in size. It takes a minimum amount of time to start. Also, it allows creating a portable operating environment for development, testing and deployment. Furthermore, multiple containers can run side by side on the same container platform.

Difference Between Container and VM

Definition

A container is a lightweight alternative to full machine virtualization that involves encapsulating an application with its own operating environment. A virtual machine (VM) is an operating system (OS) or application environment that is installed on software, which imitates dedicated hardware.

Type

Furthermore, a container is lightweight while a VM is heavyweight.

Virtualization

Container provides OS virtualization while VM provides hardware-level virtualization. This is the basic difference between container and VM.

Operating System

OS is a major difference between container and VM. All containers share the host OS, but each VM runs in its own OS.

Memory Space

Also, VM requires more memory space than a container.

Startup Time

Furthermore, the startup time of a container is in milliseconds. The startup time of a VM is in minutes.

Providers

Moroever, LXC, LXD, CGManager, and Docker are some examples for container providers whereas VMware vSphere, Virtual Box, and, Hyper – V are some examples for VM providers.

Advantages

Container reduces IP management resources, reduces and simplifies security updates, requires minimum code to transfer, migrate, and upload workloads.  VM provides all OS resources available to apps, established management and security tools. This is another difference between container and VM. 

Security

In addition, security too contributes to a difference between container and VM. Containers provide process-level isolation, which is less secure. VMs, however, are fully isolated and are more secure.

Conclusion

In brief, the main difference between container and VM is that a container provides OS-level virtualization while a VM provides hardware-level virtualization. Moreover, most companies use these technologies as they reduce the cost and improve the performance.

Reference:

1. “Virtual Machine.” Wikipedia, Wikimedia Foundation, 11 Oct. 2018, Available here.
2. “Container.” Container Definition, Available here.

Image Courtesy:

1. “OS vs Hardware virtualization” By RicoRico – Own work (CC0) via Commons Wikimedia
2. “docker” By Linux Screenshots (CC BY 2.0) via Flickr