Docker
- Run multiple isolated applications on a single host operating system without installing their dependencies system-wide.
- Package an application’s required tools and libraries together so it behaves the same on development and production hosts.
- Run separate services (web server, database, cache) in isolated containers on the same host to simplify management and scaling.
Definition
Section titled “Definition”Docker is a type of virtualization technology that allows users to run multiple isolated applications on a single host operating system. This can be useful for running different applications that have different system requirements on the same computer and for moving applications between hosts without worrying about compatibility issues.
Explanation
Section titled “Explanation”Docker enables packaging an application together with the tools and libraries it needs so the application runs consistently across environments. Instead of installing specific toolchains and libraries directly on a developer’s machine or on a production server, those dependencies are included in a container. Containers run on the same host OS but remain isolated from one another, which reduces compatibility problems and makes it easier to manage and move applications between hosts. For multi-component systems, each service can run in its own container on the same host, simplifying management and allowing the system to be scaled by adding more containers.
Examples
Section titled “Examples”Development environment
Section titled “Development environment”When a developer works on a new application, they often need a specific set of tools and libraries to compile and run the code. These tools and libraries may conflict with other applications or differ from those on the production server. With Docker, the developer can create a container that contains all necessary tools and libraries and run the application inside that container, ensuring it runs the same way in development and in production without compatibility concerns.
Deploying web applications
Section titled “Deploying web applications”Deploying a web application often requires multiple services, such as a web server, a database server, and a cache server. Traditionally, this required multiple physical or virtual machines, each with its own operating system and software. With Docker, each service can run in its own container on the same host operating system, making it easier to manage the application’s components and to scale by adding more containers as needed.