Container

A container is a virtualisation technology that enables an application to be packaged and distributed together with all its dependencies (code, system tools, libraries, configuration settings) in an isolated and portable environment. In other words, a container includes everything needed for the application to run consistently in any environment, whether on a local server, in the cloud or in a data centre.

Containers make efficient use of the resources of the operating system on which they run by sharing the same kernel of the operating system. Furthermore, containers offer a high degree of isolation, meaning that an application running in a container does not interfere with the operation of other applications running on the same system.

In the software container industry, the free, open-source project Docker It is the industry standard and the most widely used containerisation tool worldwide.

Container specifications

Containers have the following inherent characteristics:

Standardised

Containers adhere to defined standards, such as those provided by the Open Container Initiative (OCI) or Docker. These standards set out how containers should be structured and operate so that they function in the same way across different platforms. Thus, once an application is packaged into a container in accordance with the established standards, it can run consistently on any operating system that supports those standards.

Lightweight

Containers share the same operating system kernel and include only the libraries and dependencies strictly necessary to run the application, which makes them very lightweight. This reduced size enables a quick start-up and a more efficient use of system resources, a very useful advantage in environments where many applications need to be run simultaneously.

Insurance

Containers provide a high degree of isolation between the application and the operating system on which they run, using technologies such as namespaces and cgroups in Linux. This prevents interference between applications and minimises the risk of security vulnerabilities. For this reason, containers are a secure option for running applications on shared servers or in the cloud.

Containers and Kubernetes

We have already explained that containers are like self-contained packages that contain all the dependencies and configurations needed to run an application. 

Kubernetes, on the other hand, is a a platform that simplifies the management of multiple containers, by automating tasks such as the deployment, scalability and maintenance of applications. 

Essentially, with Kubernetes we can to organise and coordinate the operation of the containers, optimising resource management and ensuring that applications run as efficiently and securely as possible. 

When used together, Kubernetes and containers provide a comprehensive and scalable solution for deploying and managing applications in cloud environments.

The difference between a virtual machine and a container

We sometimes tend to confuse these two tools, even though their use cases are quite different. To put it simply, we can tell you that a container will always be a much lighter option than a virtual machine.

Containers virtualise the operating system at application level, which means they share the same kernel. This means that they are lighter and more efficient, and run in a matter of seconds. Compared with virtual machines, they are slightly less secure, as they share the same kernel as the operating system on which they run.

For their part, virtual machines virtualise the underlying hardware, including the operating system, which allows run multiple independent operating systems on the same physical machine. However, they are significantly heavier than containers, and can take several minutes to start up. Virtual machines offer added security, as each one has its own operating system.