What is Containerization?

Containers are the new virtualization technology. They allow you to isolate applications running on the same Operating System into smaller containers. A container is essentially a fully packaged and portable computing environment:

When an application runs, it depends upon everything it requires—its binaries, libraries, configuration files, and dependencies. Containers are abstraction mechanisms that abstract the complexity of operating systems and resource management from the applications within them. The containerized application can be run on various types of infrastructure, from bare metal to virtual machines and in the cloud.

Containerization makes starting up an application much faster, so you can get started sooner. It also eliminates the need to set up a separate guest OS for every application since they share the same OS kernel. For example, it’s common for modern applications to have millions of lines of code, each of which is typically responsible for a discrete functional task.

How does containerization work?

Each container is an executable package of software running on top of a host operating system. A load balancer may serve many containers (tens, hundreds, or even thousands) concurrently, such as in the case of a complex microservices architecture that uses numerous containerized application delivery controllers (ADCs). In this setup, all containers share the same network namespace. It’s possible to isolate one container and the host machine from the others. This is useful for debugging and troubleshooting.

Think of a containerized application as the top layer of a multi-tier cake:

  • At the bottom, there’s the hardware of the infrastructure in question, including its CPU(s), disk storage, and network interfaces.
  • Above that is the host OS and its kernel—the latter serves as a bridge between the OS’s software and the underlying system’s hardware.
  • The container engine and its minimal guest OS, mainly the containerization technology being used, sit atop the host OS.
  • At the very top are the binaries and libraries (bins/libs) for each application and the apps themselves, running in their isolated user spaces (containers).

How does containerization work

Containerization as we know it is based on isolating a set of resources within a computer or a group of computers and controlling how much each one can use. Containers (LXC) are Linux processes isolated from one another and their parent process. You can run an LXC container as root, have it obtain an IP address, mount a file system, and do pretty much anything else that an LXC container can do. Its user space operates in its private area. LXC containers are the lightweight version of chroot, allowing you to sandbox multiple applications into one instance of Linux. They’re also available in a minimal form, making them ideal for use on embedded platforms.

LXC is the basis for Docker, which launched in 2013 and quickly became the most popular container technology—it’s now basically an industry standard. CoreOS wrote LXC as part of the company’s effort to develop an open-source cloud platform.

Docker contributes to the OCI specification, which specifies the image formats and runtimes that container engines use. Someone booting a container, whether using a Docker image or otherwise, can expect a similar experience, no matter the computing environment. The same containers can be run and scaled whether the user is on a Linux distribution or even Microsoft Windows. In today’s digital workspace, where employees use multiple devices, operating systems, and interfaces to get things done, cross-platform compatibility is essential.

How does containerization differentiate from virtualization?

Docker containers are designed to be contained within a shared environment; each container is treated as an independent process and shares the operating system kernel with other containers. That is not the case with virtualization.

containerization vs virtualization

  • A VM runs on top of a hypervisor, specialized hardware, software, or firmware for operating VMs on a host machine, like a server or laptop.
  • Via the hypervisor, every VM is assigned not only the essential bins/libs but also a virtualized hardware stack, including CPUs, storage, and network adapters.
  • Each VM relies on a full-fledged guest OS to run all of that. The hypervisor itself may be run from the host’s machine OS or as a bare-metal application.

Containerization provides isolation between applications and allows them to run independently of each other on the same set of resources. However, there are huge differences between the two.

  • Significant overheads are involved because all VMs have their guest OSes and virtualized kernels, plus a layer of abstraction between them and the host.
  • The hypervisor can cause performance issues, especially when running on a host OS such as Ubuntu.
  • Due to the high resource overhead associated with running multiple VMs, a host machine that might be able to run ten or more containers comfortably could struggle to support a single VM.

What are the main benefits of containerization?

Containerized apps can be readily delivered to users in a virtual workspace. Containerizing a microservices-based application, a set of F5/Nginx/Citrix ADCs, or a database (among other possibilities) is an essential step for achieving a broad range of benefits, ranging from improved agility during software development to more accessible cost controls.

More agile, DevOps-oriented software development

You can use containers to run your web apps on the multi-cloud. A variety of essential developer tools are necessary for quickly developing, packaging, and deploying containerized applications across OSes. In addition, DevOps teams and engineers can leverage containerization technologies to improve their workflows.

Less overhead and lower costs than virtual machines

A container doesn’t need to run on an entire guest operating system or require a hypervisor. Instead, it can live inside a VM. As a result, you get faster boot times, smaller memory footprints, and better performance when reducing your operating system’s footprint. Virtualization can also help organizations save money by lowering their hardware and software licensing costs. This can, in turn, lead to savings for consumers. In this way, containers help increase server efficiency and lower costs.

Fault isolation for applications and microservices

If one container fails, other containers sharing the same operating system are not affected, thanks to the user space isolation between them. That can help microservices-based applications, in which multiple different components support an application. Microservices within specific containers can be repaired, redeployed, and scaled without causing downtime to the application.

Excellent portability across digital workspaces

Containers make the ideal of “write once, run anywhere” a reality. Each container is abstracted from the host operating system and runs the same no matter what physical location it is installed in. This means it can be written for one host environment and then ported and deployed to another, as long as the new host supports the container technologies and OSes in question. Docker is not one company’s product; many different people build it up. You can run your containers reliably under Microsoft Windows in both VM environments and through Hyper-V isolation. Such compatibilities are essential because they support digital workspaces where numerous clouds, devices, and workflows interconnect.

Easier management through orchestration

It’s easy to manage containerized applications and services at scale in a Kubernetes platform, especially using Docker Swarm mode. You can use Kubernetes to orchestrate rollouts and rollbacks, perform load balancing, and restart any failing containers. Kubernetes is compatible with many containers engines, including Docker and OCI-compliant ones.

What applications and services are commonly containerized?

Containers today are not just for web applications or services – they can even run almost any type of application that in previous eras would have been traditionally virtualized or run natively on a

There are several well-established computing paradigms, including:

Microservices: The exemplary microservices architecture can be efficiently configured as a set of containers operating in tandem and spun up and down as needed.

Databases: Instead of connecting multiple databases to a central database server, which is problematic in many ways, database shards can be containerized, and each app is given its dedicated database instead.

Webservers: Using a container to spin up a web server requires just a few commands line inputs to get started, and it doesn’t require running the webserver directly on the host.
Containers within VMs: A container is an operating system instance that runs inside a virtual machine (VM) and shares resources and storage with the host machine.

ADCs: Application Delivery Controllers help you deliver your applications more securely and with lower latency. Containerization means that there are containers of the appropriate version and state.

AppViewX solutions for containerization

The components of an application are often packaged into individual microservices. They may be deployed and managed within containers on a scalable cloud infrastructure. Containers offer a variety of benefits, including minimal overhead, independently scalable, and easy management via a container orchestrator like Kubernetes. Appviewx ADC+ can help with the transition from monolithic to microservices-based applications.