Introduction
Virtual machines and containers are both virtualization technologies that are discrete yet similar when it comes to enhancing IT efficiency, providing application portability, as well as enabling better DevOps and a healthier software development lifecycle. A single system resource, such as RAM, CPU, storage, or network, can be “virtualized” and represented as several resources through the process of virtualization. Virtual machines emulate the entire system down to the hardware layer, whereas containers virtualize the software layer above the operating system layer.
Thus, the primary distinction between containers and a virtual machine is that VMs take care of the infrastructure issues to enable enterprises to make full use of servers and limit workload portability. Containers, on the other hand, resolve application-related issues by boosting DevOps & microservices, rising portability and upgrading resource utilization.
How does virtualization work?
The practice of creating a layer of abstraction over computer hardware with the support of software, known as virtualization, enables the division of a single computer’s hardware components into multiple virtual machines.
The software utilized is referred to as a hypervisor. It’s a small layer that enables simultaneous use of the physical computing resources by multiple operating systems. A physical computer or server in a data center can insulate the operating system and applications from the hardware by using a hypervisor (sometimes referred to as a bare metal server). Then, it can be divided into multiple independent or separate “virtual machines.”
Virtual Machines (VMs)
An operating system, supporting binaries, and applications are all simulated by a virtual machine (VM). It is an abstraction of the hardware layer that is included within it. The equivalent of numerous physical servers can be run on a single physical server using virtual machine technology (VM). As a result, each virtual machine running on a physical machine has its copy of the operating system, applications, and the files, libraries, and dependencies that go with it.
VMs, which came into being, before containers, have significantly changed the way how numerous programs could be delivered on pre-existing machines. Prior to virtual machines, each application used to run on a different physical system. A hypervisor controls and manages a VM, which is realized by the VM hardware, where the hypervisor is a consolidation of hardware, firmware, or software that manages and monitors virtual machines (VMs). Each virtual machine (VM) supported by a hypervisor has its operating system.
A VM is also known as a virtual server, virtual server instance, or virtual private server. Some of the popular virtual machine providers are virtual box, VMware, QEMU to name a few.
Pros of a Virtual Machine
- Decades of experience in virtualization give you access to a robust suite of VM management and security tools.
- VMs provide the ability to run multiple applications requiring different operating systems on a single infrastructure.
- A VM emulates an end-to-end computing environment including all operating system resources.
- Virtual machines (VMs) make migrating between on-premises and cloud-based platforms easier.
Cons of a Virtual Machine
- VM images frequently use gigabytes, which makes backing them up or moving them between platforms more difficult.
- Physical servers can support fewer VMs than containers because they encapsulate the entire server, including the operating system.
- Spinning up the VM may take a few minutes.
Containers
A container is an abstraction of the software layer that replicates the logical packaging of an application with the necessary binaries embedded within it. The running environment is isolated from the encapsulated container. This makes it simple to install container-based apps, regardless of the target environment, which could be a personal computer, a public cloud, or even a private data center. A microservice or even a software process for a larger application can run in a single container. The orchestrator, which is often offered by the containerization platform, oversees the resources utilized by the container and facilitates OS-level communications. Containers are deployed utilizing virtual-memory hardware.
Some of the popular container providers are Docker, RKT, LINUX Containers (LXC), CRI-O.
Pros of Containers
- Since container pictures are measured in megabytes rather than gigabytes, they are lighter than virtual machines.
- Less IT resources are needed to deploy, operate, and manage containers.
- Containers begin spinning in milliseconds.
- They are smaller in magnitude.
- Compared to virtual machines, a single system can host many more containers.
Cons of Containers
- All containers must run on the same operating system. Operating systems or versions cannot be mixed.
- Containers can be less secure than VMs because the underlying operating system is shared.
- Containers are a fairly new technology, and the ecosystem is still evolving with them.
Containers and Virtual Machines – The key differentiators
A hypervisor virtualizes physical hardware in traditional virtualization methodology. Because of this, each virtual machine includes a guest operating system, a virtual replica of the hardware needed to run the operating system, as well as applications and the libraries and dependencies that go with them. On the same physical server, VMs running under different operating systems can also run on it. A VMware virtual machine can coexist alongside a Linux virtual machine and a Microsoft virtual machine, for instance.
Containers enable developers to increase the CPU and memory utilization of actual devices, just as virtual machines do. However, containers go one step further since they also offer microservice architecture, which allows for more precise deployment and scaling of application components. This is a more worthwhile option than trying to scale up an entire monolithic application just because one component is experiencing load issues.
Conclusion
Regardless of the similarities and differences between virtual machines and containers, it is observed that containers offer a unique mechanism to virtualize an operating system so that numerous workloads can execute on a single OS instance. The hardware is virtualized with VMs so that several OS instances can run on it. Containers are yet another technology that can be used to speed up the software development lifecycle ensuring more agility and portability on the go.