Introduction
Virtual Machines (VMs) and Containers have both dramatically impacted the world of software development and deployment. Each has its unique features, and the choice between VMs and Containers often depends on the needs of a specific project or infrastructure. Let's dive into both of these technologies and explore their histories, uses, and some benefits and drawbacks.
Virtual Machines (VM): The Groundbreakers
Brief History and Evolution
Virtual Machines date back to the 1960s, when IBM introduced a mainframe computing system capable of time-sharing, a technique that allows multiple users to share the computing resources of one mainframe. Fast-forwarding to the 2000s, companies like VMware popularized VM technology, allowing us to abstract the physical hardware into several different VMs.
The Need for VMs
Virtual Machines allow you to run multiple operating systems on the same physical hardware, significantly improving both hardware utilization and maintenance. Each VM can run its OS, making it an entire IT infrastructure in a box. However, this results in a larger overhead as each VM carries a full OS with it.
Containers: The Modern Era
Brief History and Evolution
Linux Containers (LXC) existed for quite some time before Docker was introduced in 2013 and quickly caught the attention of the development community. Unlike VMs, Containers share the host system’s kernel with other containers. This makes them lightweight, as they don't need a full OS for each one.
The Need for Containers
Containers package the application code and all of its dependencies so the application runs quickly and reliably from one computing environment to another. This Docker-style, OS-level virtualization technology creates lightweight, portable, and self-sufficient containers. This need was born out of the widespread adoption of microservices architecture, where decoupled services often require different runtime environments.
VMs vs Containers: A comparison
- Efficiency and Speed: Containers are lightweight and fast since they run directly on the host machine's OS without the overhead of running an entire OS for each application. On the other hand, VMs include a full copy of an OS, the application, necessary binaries, and libraries - taking up tens of GBs. VMs also might take several minutes to boot up, while containerized apps can be started almost instantly.
- Portability: Containers can be run on any system that supports container runtime (like Docker), making them more portable. VMs, on the other hand, require a hypervisor, which usually implies that a VM solution will be tied to a particular VM provider.
- Isolation: VMs provide strong isolation as they have separate OS, while containers have less strict isolation as they share the OS kernel.
- Security: As VMs are fully isolated from one another, they provide a better security boundary in comparison to containers.
VMs and Containers in Modern Deployment
Today's trend leans towards using a hybrid solution that benefits from both VMs and containers. A common practice is to use VMs as host systems that run containers. This approach takes advantage of the resource segregation of VMs while also benefitting from the lightweight nature of containers.
Many cloud providers like AWS, GCP (Google Cloud Platform), and Azure provide services to run containerized applications. Kubernetes, the widely adopted container orchestration tool, can create, deploy, and manage containers across multi-node clusters that can reside on a cloud VM.
Conclusion
Virtual Machines and Containers serve different purposes and have unique advantages. VMs are suitable for running applications that require all of the operating system's resources and functionality, while containers are better for running multiple instances of a single or closely related set of applications. So, choosing between a VM and a container depends primarily on the use case, which could be as diverse as the development ecosystem itself. With the evolution of technology, the integration of VMs and containers provides a way forward for software deployment, enabling organizations to get the best of both worlds.