What is a virtual machine?

A virtual machine, or VM, is a complete software emulation of a physical computer system. It includes its own operating system as well as dedicated resources, which allows it to run completely independently of other applications on the host server. Unlike containers, virtual machines require more hardware resources because they each have a complete operating system. However, they offer a higher level of control over the environment, making them suitable for applications that require strict isolation and a dedicated environment.

What is a container?

A container is a lightweight, isolated environment that bundles the code of an application, its dependencies and libraries, allowing the application to run consistently and portably on different operating systems. Containerization makes the application independent of the underlying operating system, ensuring that the same code runs correctly no matter where the container is deployed. This technology also enables fast startup and efficient use of resources, making it a preferred choice for modern applications, especially in the context of agile development and microservices.

Common uses of containers and virtual machines

Containers and virtual machines are widely used in enterprises to improve the flexibility and efficiency of application deployment. Containers are particularly popular in agile development environments where portability, speed of deployment and lightness are essential. Virtual machines, on the other hand, are often deployed in environments where system isolation is critical, such as mission-critical application servers or environments that require specific resources. Companies can combine the two technologies to benefit from the respective advantages according to the specific needs of each application.

Similarities between containers and virtual machines

Although fundamentally different, the two container and virtual machine technologies share important similarities. Both allow applications to be isolated so that they can run independently, thus providing an abstraction of the underlying hardware infrastructure. This allows companies to manage separate environments without affecting the host system. In addition, containers and virtual machines allow software components to be grouped into images (image files), which simplifies deployment and configuration management.

Virtual Machines vs containers

Technological differences

Containers and virtual machines differ fundamentally in their approach to virtualization. Containers virtualize only the operating system, allowing the host OS kernel to be shared between different instances, reducing their weight and improving performance. Virtual machines, on the other hand, virtualize all the hardware infrastructure and integrate their own operating system. This distinction allows VMs to operate completely independently, but also makes them larger and increases the resources required for their execution.

Performance and size

Due to their lighter design, containers are often much smaller than virtual machines, resulting in faster startup times and more optimized resource use. Containers are measured in megabytes (MB), while virtual machine images can be up to several gigabytes (GB) because they include the entire operating system. This size difference makes containers particularly suitable for applications requiring fast start-ups and frequent deployment. Virtual machines, on the other hand, are better suited to more complex applications requiring dedicated and stable environments.

Resource and Cost Management

Containers and virtual machines also differ in terms of resource management and associated costs. Containers, being lighter, use less memory and CPU, which optimizes hardware resources and reduces infrastructure costs, especially in cloud environments where billing is based on usage. The virtual machines, being heavier, require more storage and resources to run. Although they are generally more expensive, VMs remain essential for applications that require an isolated environment with a complete operating system.

Safety and Isolation

Both containers and virtual machines offer solutions to secure and isolate applications, although they do so in different ways. Virtual machines offer a high level of isolation, with each VM running on its own operating system. This separation limits the risk of contamination between applications in case of a security breach. Containers, although isolated from each other, share the core of the host operating system, which can increase security risks in case of OS vulnerability. However, practices such as the use of immutable containers and strict container image management can enhance security.

Flexibility and Scalability

Containers are highly flexible and easily extensible, making them a preferred choice for microservice-based architectures. Thanks to their low memory footprint, they allow the scaling of individual components of an application without significantly increasing resource use. Virtual machines also offer scalability options, but their requirements for hardware resources make this process more expensive and complex. For companies that need granular scaling capacity, containers provide a more cost-effective and flexible solution.

Basic technology

Containers and virtual machines rely on separate core technologies for their management. Virtual machines use hypervisors, software that allows the creation and management of multiple operating systems on a single host, such as VMware or Hyper-V. However, containers use container engines, as Docker, who act as intermediaries between the container and the underlying operating system to coordinate and allocate resources. These technologies allow containers and VMs to operate autonomously and provide good isolation of applications.

Choosing containers: when and why?

Containers are ideal for development and production environments where speed and portability are essential. They are particularly suitable for teams that adopt agile methodologies and require frequent deployment cycles. Lightweight containers allow developers to quickly test changes and experiment with new features without compromising performance. Containers are also a preferred choice for microservices architectures, where each component of an application can be deployed, updated and scaled independently.

Choosing virtual machines: When and why?

Virtual machines are recommended for applications that require full control of the environment or for systems that must run in an isolated setting. Businesses often use them to run applications that require specific configurations of operating systems or hardware, without interfering with the host OS. VMs are also ideal for test environments where you need to take snapshots of the system state and easily go back. In addition, they can simulate complex network infrastructures, making them a suitable choice for heavy applications and stable production environments.

Practical use cases

The use cases of containers and virtual machines vary according to the specific needs of companies and applications. For example, containers are often used in SaaS applications to deploy standalone functionality or in CI/CD platforms to accelerate testing and deployments. Virtual machines are common in environments that require full emulation of infrastructure, such as ERP applications and sensitive data management systems. This diversity of applications shows the complementarity of both technologies and allows companies to optimize their processes according to the requirements of each application.

UNIVIRTUAL solutions for managing virtual machines and containers

UNIVIRTUAL offers a range of solutions to support companies in the deployment and management of their infrastructures, whether they rely on containers, virtual machines or a combination of both. With a strong expertise in virtualization and containerization, UNIVIRTUAL helps its customers to choose the best technology according to their needs, while optimizing costs and security. UNIVIRTUAL solutions include deployment, real-time monitoring and orchestration services, enabling simplified management and increased adaptability for enterprises. Whether for a hybrid, multi-cloud infrastructure or large-scale applications, UNIVIRTUAL provides the tools and guidance for an agile and powerful environment.

Contact our specialized teams to benefit from the advice of our experts to choose the most suitable solution for your needs.