Docker Containers: an absolute prevail over Virtual Machines
By: Vladimir Fedak
Tags: Docker, Virtual Machine, Kubernetes, Cloud, Workflow

Docker containers allow the developers to run their apps in any environment, be it bare metal servers, cloud or virtual machines. Why don’t we drop the VMs for good then?

The main idea of a Docker container is that once the Docker image is created, the container with it can be easily built and run in any environment — and it will behave exactly the same wherever it runs. This means that regardless of the underlying infrastructure, operating system, installed software, and other variables, the app will always run, as it has its runtime environment in the container. However, despite certain benefits we mentioned in our Docker vs Vagrant comparison, containers are not universal.

Below we list several points to consider when choosing between containers and VMs:

Containers provide more operational agility Containers underpin multi-cloud and hybrid systems Containers are easily integrated with existing IT workflows Containers are cheaper than VMs Containers are inherently more secure

This is a brief overview of the points above.

More operational agility

Docker containers are built and launched according to scripts, so 1 command provides everything a developer needs. Every time a new VM is provisioned, it must be configured and all the needed software must be installed and configured before it can be used. Containers can be rebooted in a matter of seconds while rebooting an app running on a VM requires restarting the VM and all the required services.

Cornerstones of multi-cloud and hybrid systems

As containers run equally well anywhere, they can be easily used as building blocks for distributed multi-cloud systems, spanning across multiple availability zones and using various features of different providers. They can also work wonders in hybrid systems, where some parts of the infrastructure are deployed to the public cloud and mission-critical systems are kept on-prem or in a private virtual environment.

Ease of integration with the existing IT infrastructure

Mature companies have built their unique IT infrastructures around certain tools, workflows, people and skills. Once your IT department grasps the basic concepts of Docker containers, they will see multiple ways of integrating them into your unique software ecosystem. The main purpose of this process is reducing the time needed for app deployment, and removing the “works well on my machine” situation, plaguing the software delivery pipelines of many businesses.

Containers are much cheaper than VMs

Containerized apps share the same OS, libraries and other components, allowing to save a ton of computing resources when deploying at scale. Actually, due to removing the hypervisor layer and consolidating the virtualized resources, containers are 300% more cost-effective, as compared to VMs.

Containers are inherently more secure

Containers have multiple security layers and form a protective layer for the virtual host or bare metal server they run on. Every set of security restrictions within the container protects both the host and all the colocated containers, working well with the whole range of virtualization security features.

Final thoughts on why Docker containers prevail over Virtual Machines

For all the reasons above, Docker containers gain the ever-increasing importance for software delivery and production maintenance. However, there are multiple reasons why they cannot become the mainstay of the software development. First of all, virtual machine software like Vagrant or vSphere is designed specifically to support the software development pipelines and works great in tandem with multiple Big Data Analytics tools, monitoring solutions and code version control systems.

Secondly, full-scale migration to the cloud and transition to using Kubernetes clusters can be quite a costly endeavor, especially for matured enterprise IT infrastructures. Thus said, it can be done and it must be done, one project at a time — but till all the workloads move to working on Kubernetes, virtual machines must do.

Is your company still running virtual machines or have you containerized your workloads already? Which approach suits your operational profile best? Please let us know below!