Docker vs VM(Virtual Machine)

Docker and virtual machines both serve the purpose of replicating development environments and improving dependency and configuration management. However, it is important to be aware of the differences between them in order to make an appropriate choice between using a virtual machine or a Docker container, depending on the specific needs of the application.

What is Docker?

Docker is an open-source software platform that simplifies the deployment and management of applications by using containerization A type of virtualization in which all the components of an application are bundled into a single container image.. Containers are lightweight, isolated environments that package an application along with its dependencies, libraries, and configuration files. They allow applications to run consistently across different computing environments, irrespective of the underlying infrastructure or operating system.

What is VM (Virtual machine)?

A virtual machine (VM) is a software emulation of a physical computer system. It allows users to run multiple operating systems and applications on a single physical machine simultaneously. A VM operates as an isolated environment within the host computer, providing resources such as CPU, memory, storage, and network connectivity. The virtualization layerA layer that lies between the hardware and OS., known as the hypervisor, manages the VMs and allocates resources to each.

Operating system support

• Docker containers run on top of a host operating system and are highly dependent on it. This means that Docker can run on any operating system that supports containerization. However, containerized applications must be compatible with the host operating system.

• VMs can run different operating systems, including Windows, Linux, macOS, etc. Each VM can have its own operating system version and configuration, making it more flexible in terms of operating system support.

Performance

• Docker containers have lower overhead since they share the host operating system kernel. This results in improved performance and more efficient resource utilization. Containers start quickly and require fewer resources compared to VMs.

• VMs have additional overhead because they run a separate operating system instance, which consumes more system resources. VMs take longer to start compared to Docker containers.

Isolation

• Docker containers provide process-level isolation, meaning that processes running inside containers are isolated from one another. However, they share the same kernel, which poses a security risk if a vulnerability is exploited.

• VMs offer stronger isolation because each VM runs its own kernel and has a separate operating system instance. This isolation provides better security but comes at the cost of increased resource consumption.

Use cases

• Docker is suitable for applications that require lightweight virtualization, fast deployment, and scalability. It is commonly used for micro-services architectures, containerized applications, continuous integration/continuous deployment (CI/CD), and container orchestration with tools like Kubernetes.

• VMs are ideal for running applications that require complete operating system isolation, such as legacy systems, different operating systems, or running multiple applications on a single physical server.

Which one should you use?

The best choice for you will depend on your specific needs. If you need to run applications that require a specific operating system or environment, then a VM is a good choice. If you need to run applications that are lightweight and portable, then Docker containers are a good choice.

Here are some additional factors to consider when choosing between Docker containers and VMs:

• Budget: VMs can be more expensive to set up and maintain than Docker containers.

• Technical expertise: Docker containers are easier to set up and manage than VMs, if you are not familiar with Linux.

• Application’s requirements: If your application requires a specific operating system or environment, then a VM is a good choice. If your application is lightweight and portable, then Docker containers are a good choice.

Conclusion

Here is a table which concludes on a virtual machine and Docker container differences.