Container is a software package that includes everything necessary to run software: an application, its dependencies, libraries and system tools. This ensures the smooth operation of the software, regardless of the environment in which it is deployed.
How containers differ from VMs (virtual machines)
To better understand the concept of containers, it is useful to compare them with more familiar virtual machines (VMs). VMs and containers are designed to create an isolated environment for applications to run. However, if all hardware is virtualized in the VM, then the operating system is virtualized in the containers. This makes containers much easier and faster to launch than VMs.
The internal structure of the container
A container consists of two main components: the container image and the container runtime environment. A container image is an executable software package containing all the components to run the software. The container runtime is the software that runs and manages containers.
Advantages of using containers
Containers have numerous advantages, including:
- portability. Since containers contain everything necessary for the operation of the application, they can be transferred from one computing environment to another without any difficulties;
- effectiveness. Containers are lightweight and require less system resources than traditional VMs, which allows you to run more containers on this equipment;
- scalability. Containers can be easily increased or decreased depending on needs, making them an ideal solution for applications with variable workload;
- isolation. Each container runs in its own isolated environment, which ensures that the operation of the application inside the container is not affected by changes in other containers or the host system.
The use of containers
Containers have found wide application in various fields. They are used in the architecture of microservices, where each microservice operates in its own container. Containers are also used in continuous integration and continuous deployment (CI/CD) pipelines to ensure consistency at different stages of the development process.