What are containers actually used for?

Container 101: What is container technology, what is Kubernetes and what are both used for?

By Richard Harris, Joel Nelson -

What are containers?

With the help of containers, applications run consistently and reliably - regardless of operating systems or infrastructure environments. Containers bundle all the components that a service needs to operate. This includes codes, runtimes, system tools and libraries as well as settings. This creates a portable, independent and executable package.

What are containers used for?

Containers represent the future of computing - alongside technologies such as DevOps, cloud-native approaches, AI and machine learning. Typical use cases include:

  • the modernization of existing applications in the cloud;
  • creating new applications to maximize the benefits of containers;
  • isolating, deploying, scaling, and supporting microservices and decentralized apps;
  • increasing DevOps efficiency / performance through optimized development processes / tests / deployments;
  • providing developers with consistent production environments that function in isolation from other applications and processes;
  • the simplification and acceleration of repetitive functions as well
  • the support of hybrid and multicloud computing environments, since containers can be operated consistently everywhere.

What is containerization?

Part of containerization, i.e. the creation of a container, is to extract only the required application or service as well as the associated dependencies and configurations. As a result, these are separated from the operating system and the underlying infrastructure. The resulting container image can be operated on any container platform. Multiple containers can run on the same host. They share the same operating system with other containers. However, isolated processes are carried out in separate and secure locations. Since containers share the basic operating system, the individual container can be operated with significantly fewer resources than a separate virtual machine (VM).

What are the advantages of containers?

  • Containers are compact: Because they are isolated from the operating system layer, containers work more efficiently and use fewer resources than virtual machines.
  • Containers are portable: Containers already contain all dependencies and configurations. It is possible to write in a container and flexibly switch between environments.
  • Containers are scalable: Because containers are so compact, they can be set up and scaled quickly. They shut down quickly when not in use and back up just as quickly when needed.
  • Containers can be inexpensive: Due to the reduced need for resources and intelligent scaling, containers are a resilient, fast and cost-effective solution.
  • Containers require less infrastructure: Working with containers requires that you carefully study your requirements in order to offer the best customer experience. This process reduces the need for infrastructure and thus also the administrative effort.
  • Containers provide more focus: IT teams spend less time on guest operating systems and physical hardware. The team can use the time gained to work on projects that are critical to the company.
  • Containers accelerate development: Containers provide a stable, predictable environment that is optimized for CPU and memory, and where code is abstracted from the infrastructure for portability.
  • Containers use modern system architecture: With the help of containers, developers can divide applications into microservices. This accelerates development and ensures individual scaling after deployment.

What are the challenges associated with containers?

  • Containers are pretty new: Kubernetes was first released in 2014 and quickly established itself in the market. Due to its status as a novel technology trend, it can be difficult to find seasoned technologists who know how to work in containerized environments.
  • Not all services are containerized: If your application relies on services that are not containerized, you may have to invest a lot to turn them into a containerized solution.
  • Containers require changes in terms of processes and competencies: Containers can accelerate the transition to more agile, efficient development. However, this can mean significant changes to your current development, deployment, review, and monitoring processes. Existing teams may therefore need to be retrained.
  • Technologies are developing rapidly: This doesn't just apply to containers. However, this rapid pace of development means that you need employees (or partners) to make informed decisions, reduce risk and ensure that implementations are not disrupted by sluggish processes within your company.
  • Containers are not a universal solution: At first glance, containers may seem like the perfect solution, but every change also requires serious consideration. You need to understand what basis you are working on, what suits your needs and what doesn't. Alternatively, you can also consider working with a partner who can help you make the switch.

Containers vs. virtual machines

Containers and virtual machines are to be understood as "packages". A container is a package that contains your application and everything it needs to run - with the exception of the operating system. A virtual machine contains your application and everything that is necessary for its operation - including the operating system.

You can operate several containers on one operating system. You can also install several virtual machines on one piece of hardware. You can even run containers on virtual machines.

A major advantage of containers over virtual machines is that containers require less system resources and effort because the operating system is not included. As a rule, they can be started up and shut down more quickly and used flexibly in different environments. In the idle state, however, they still occupy infrastructure capacities and thus drive up costs.

Docker vs. Kubernetes

Docker's technology enables containers to be created and executed - the company's containers are industry standard. Kubernetes (abbreviated k8s) enables the management (or orchestration) of all your containerized workloads, including provisioning, networking, load balancing, backup and scaling. Docker can be operated independently without Kubernetes, but Kubernetes cannot run without container services like Docker.

As of 2021, Docker has practically the entire market share in the containerization sector. There are many competing Kubernetes products out there, and 50% of the organizations StackRox surveyed have self-managed Kubernetes applications installed. The top five are self-managed Kubernetes applications (50%), Amazon EKS (44%), Azure AKS (31%), RedHat OpenShift (22%) and Amazon ECS (20%).

What is container orchestration?

If you only have a handful of containers and two or three applications, container orchestration may not be necessary. But as soon as these numbers increase, so does complexity. Kubernetes' container orchestration enables the automatic provisioning, scaling, and management of thousands of containerized applications.

The benefits of Kubernetes container orchestration include:

  • Service discovery and load balancing;
  • the automatic integration of the storage system of your choice;
  • automated rollouts and rollbacks;
  • the optimal use of resources;
  • automatic repair of Kubernetes (restarting failed containers; terminating containers that do not respond to user-defined functional tests)
  • Ways to store and manage sensitive information as well
  • Deployment and update of configurations without re-creating the container images.

What are the main tools and technologies related to containers?

Docker and Kubernetes are the front runners in the container sector. Docker is an open source based container platform. Kubernetes is the most popular choice for container orchestration - although there are alternatives like Docker Swarm and VMware Tanzu. Leading cloud providers such as AWS, Google and Microsoft Azure also offer “Containers as a Service” (CaaS) products.

When should you choose containers or consider another option?

Containers are a great option if you're building an application from scratch, adopting a microservices-based architecture, or looking for a flexible solution that you can build once and deploy anywhere. But what about your existing, monolithic applications?

Some physical machines cannot be moved to virtual machines, so applications that require a lot of resources may not be a good choice for containerization. To convert an application with high CPU and RAM requirements into a container, you need to change how it works. In this case, the long development time and the necessary financial resources would be disproportionate to the benefit provided.

Rackspace Technology container solutions

The experts at Rackspace Technology have extensive experience in the architecture and design of platform solutions for containerization. We take an independent approach and use the container orchestration platform that brings you the greatest benefit - via Kubernetes, DockerSwarm and Rancher as well as cloud-native tools such as ECS, EKS, AKS and GKE. At the beginning of your containerization, our specialists work closely with you to understand the architecture of your applications. The next step is to design and build a complete container solution that integrates networking, disks, computing resources, and more. Start containerization today.

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