Docker

Docker has profoundly changed the software landscape and is now a key building block for microservices and cloud architectures. Before Docker, developers often faced the same problem: "It runs on my computer, but not on the server." This was because software usually depends on specific libraries, runtime environments, and configuration files, which required a lot of effort to install in order to get the software running. Different installation paths and small version differences could lead to subtle errors.

Docker provides a solution. With Docker, you can encapsulate software and all its dependencies in so-called containers and run them in isolation. Docker consists of three components: The application and all required libraries, runtime environments, and configuration files are installed on a Docker image. The image can then be copied to a container. This is handled by the Docker runtime, a runtime environment that ensures that the containers can be started, executed, and managed.

Many microservices and cloud environments today are largely based on this architecture. Each service can run independently in its own container and communicate with each other via web protocols. Running each service in an isolated environment with precisely defined dependencies minimizes potential conflicts with other software. Furthermore, a Docker container requires fewer resources than virtual machines (VMs), allowing it to run more efficiently and scale better.

Because Docker's source code was released as open source, a large community and ecosystem of applications quickly developed. Kubernetes allows containers to be managed and monitored more efficiently, and Docker integrations exist for many developer tools. Docker has made software more portable, scalable, reproducible, and team-friendly, making it ideal for dynamic, scalable systems—especially in the cloud environment.