A container is a software package that bundles all essential components (your application code, runtime, system tools, libraries, settings, and other dependencies) so that it can run in any environment.
A container does not have its own kernel but uses the kernel of the OS (operating system) that runs the container. This allows a container to run operating systems and applications that are compatible with the host's kernel. For example, if the host is a Linux VPS, the container can contain Linux applications and OSes.
A container virtualizes an operating system and can therefore be run anywhere, whether it's on your computer, in the cloud, or in your own data center. Some advantages of using containers are:
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Workload portability: containers can run on practically any operating system and on both virtual machines and physical hardware. This makes deploying applications easier.
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Lighter than a virtual machine: Containers virtualize at the OS level while virtual machines virtualize at the hardware level. Essentially, this means that with a virtual machine, you manage an operating system but not with a container. On the TransIP Kubernetes platform, for example, this means that you no longer manage an operating system but only your application.
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Clearer separation of duties: developers (e.g. yourself) only need to focus on the application itself and its dependencies. Another team or party (e.g. TransIP for our Kubernetes platform) focuses on deployment and management of the platform.
- Isolation of your application: Containers virtualize hardware resources (CPU, RAM, storage, network) at the level of the operating system. This makes it much clearer to see how your application uses resources.