mirror of https://github.com/docker/docs.git
99 lines
3.8 KiB
Markdown
99 lines
3.8 KiB
Markdown
---
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title: "Overview"
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keywords: get started, overview, quickstart, intro, concepts, containers, images
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description: Get an overview of the Get started guide and learn about containers and images.
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---
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Welcome! We're excited that you want to learn Docker.
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This guide contains step-by-step instructions on how to get started with Docker. Some of the things you'll learn and do in this guide are:
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- Build and run an image as a container
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- Share images using Docker Hub
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- Deploy Docker applications using multiple containers with a database
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- Run applications using Docker Compose
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Before you get to the hands on part of the guide, you should learn about containers and images.
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## What is a container?
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Simply put, a container is a sandboxed process on your machine that is isolated from all other processes on the host machine. That isolation leverages [kernel namespaces and cgroups](https://medium.com/@saschagrunert/demystifying-containers-part-i-kernel-space-2c53d6979504),
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features that have been in Linux for a long time. Docker has worked to make these capabilities approachable and easy to use. To summarize, a container:
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- is a runnable instance of an image. You can create, start, stop, move, or delete a container using the DockerAPI or CLI.
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- can be run on local machines, virtual machines or deployed to the cloud.
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- is portable (can be run on any OS).
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- is isolated from other containers and runs its own software, binaries, and configurations.
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## What is a container image?
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When running a container, it uses an isolated filesystem. This custom filesystem is provided by a container image. Since the image contains the container's filesystem, it must contain everything needed to run an application - all dependencies, configurations, scripts, binaries, etc. The image also contains other configuration for the container, such as environment variables, a default command to run, and other metadata.
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You'll dive deeper into images later on in this guide, covering topics such as layering, best practices, and more.
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> **Note**
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>
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> If you're familiar with `chroot`, think of a container as an extended version of `chroot`. The filesystem is simply coming from the image. But, a container adds additional isolation not available when simply using chroot.
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## Next steps
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In this section, you learned about containers and images.
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In the next section, you'll containerize your first application.
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[Containerize an application](02_our_app.md){: .button .primary-btn}
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