# Docker {% embed url="" %} Docker - Testing and Deployment {% endembed %} ## Summary * Docker is a computer program that performs operating-system-level virtualization, also known as **containerization**. * A container is a standardized unit of fully packaged software used for local development, shipping code, and deploying system. * Though Docker presents on how to deal with each of the individual microservices, we also need an orchestrator to handle the whole cluster of services. For that, **Kubernetes** is the open-source winner, and it has excellent support from the leading cloud vendors. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://fall2019.fullstackdeeplearning.com/course-content/testing-and-deployment/docker.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.