0056884090
1. Re-aligns the introduction with the new product positioning. 2. Cleanup of some issues with language and formatting. 3. Makes the introduction leaner and meaner. 4. Responds to feedback from product. Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
292 lines
9.7 KiB
Markdown
292 lines
9.7 KiB
Markdown
page_title: Introduction to working with Docker
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page_description: Introduction to working with Docker and Docker commands.
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page_keywords: docker, introduction, documentation, about, technology, understanding, Dockerfile
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# An Introduction to working with Docker
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**Getting started with Docker**
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> **Note:**
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> If you would like to see how a specific command
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> works, check out the glossary of all available client
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> commands on our [Commands Reference](/reference/commandline/cli).
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## Introduction
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In the [Understanding Docker](understanding-docker.md) section we
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covered the components that make up Docker, learned about the underlying
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technology and saw *how* everything works.
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Now, let's get an introduction to the basics of interacting with Docker.
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> **Note:**
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> This page assumes you have a host with a running Docker
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> daemon and access to a Docker client. To see how to install Docker on
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> a variety of platforms see the [installation
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> section](/installation/#installation).
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## How to use the client
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The client provides you a command-line interface to Docker. It is
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accessed by running the `docker` binary.
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> **Tip:**
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> The below instructions can be considered a summary of our
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> [interactive tutorial](https://www.docker.io/gettingstarted). If you
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> prefer a more hands-on approach without installing anything, why not
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> give that a shot and check out the
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> [tutorial](https://www.docker.io/gettingstarted).
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The `docker` client usage is pretty simple. Each action you can take
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with Docker is a command and each command can take a series of
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flags and arguments.
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# Usage: [sudo] docker [flags] [command] [arguments] ..
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# Example:
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$ docker run -i -t ubuntu /bin/bash
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## Using the Docker client
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Let's get started with the Docker client by running our first Docker
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command. We're going to use the `docker version` command to return
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version information on the currently installed Docker client and daemon.
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# Usage: [sudo] docker version
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# Example:
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$ docker version
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This command will not only provide you the version of Docker client and
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daemon you are using, but also the version of Go (the programming
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language powering Docker).
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Client version: 0.8.0
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Go version (client): go1.2
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Git commit (client): cc3a8c8
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Server version: 0.8.0
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Git commit (server): cc3a8c8
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Go version (server): go1.2
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Last stable version: 0.8.0
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### Seeing what the Docker client can do
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We can see all of the commands available to us with the Docker client by
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running the `docker` binary without any options.
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# Usage: [sudo] docker
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# Example:
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$ docker
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You will see a list of all currently available commands.
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Commands:
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attach Attach to a running container
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build Build a container from a Dockerfile
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commit Create a new image from a container's changes
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. . .
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### Seeing Docker command usage
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You can also zoom in and review the usage for specific Docker commands.
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Try typing Docker followed with a `[command]` to see the usage for that
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command:
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# Usage: [sudo] docker [command] [--help]
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# Example:
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$ docker attach
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Help output . . .
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Or you can also pass the `--help` flag to the `docker` binary.
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$ docker images --help
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This will display the help text and all available flags:
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Usage: docker attach [OPTIONS] CONTAINER
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Attach to a running container
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--no-stdin=false: Do not attach stdin
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--sig-proxy=true: Proxify all received signal to the process (even in non-tty mode)
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## Working with images
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Let's get started with using Docker by working with Docker images, the
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building blocks of Docker containers.
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### Docker Images
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As we've discovered a Docker image is a read-only template that we build
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containers from. Every Docker container is launched from an image. You can
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use both images provided by Docker, such as the base `ubuntu` image,
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as well as images built by others. For example we can build an image that
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runs Apache and our own web application as a starting point to launch containers.
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### Searching for images
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To search for Docker image we use the `docker search` command. The
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`docker search` command returns a list of all images that match your
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search criteria, together with some useful information about that image.
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This information includes social metrics like how many other people like
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the image: we call these "likes" *stars*. We also tell you if an image
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is *trusted*. A *trusted* image is built from a known source and allows
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you to introspect in greater detail how the image is constructed.
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# Usage: [sudo] docker search [image name]
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# Example:
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$ docker search nginx
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NAME DESCRIPTION STARS OFFICIAL TRUSTED
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dockerfile/nginx Trusted Nginx (http://nginx.org/) Build 6 [OK]
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paintedfox/nginx-php5 A docker image for running Nginx with PHP5. 3 [OK]
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dockerfiles/django-uwsgi-nginx Dockerfile and configuration files to buil... 2 [OK]
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. . .
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> **Note:**
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> To learn more about trusted builds, check out
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> [this](http://blog.docker.io/2013/11/introducing-trusted-builds) blog
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> post.
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### Downloading an image
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Once we find an image we'd like to download we can pull it down from
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[Docker.io](https://index.docker.io) using the `docker pull` command.
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# Usage: [sudo] docker pull [image name]
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# Example:
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$ docker pull dockerfile/nginx
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Pulling repository dockerfile/nginx
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0ade68db1d05: Pulling dependent layers
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27cf78414709: Download complete
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b750fe79269d: Download complete
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. . .
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As you can see, Docker will download, one by one, all the layers forming
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the image.
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### Listing available images
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You may already have some images you've pulled down or built yourself
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and you can use the `docker images` command to see the images
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available to you locally.
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# Usage: [sudo] docker images
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# Example:
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$ docker images
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REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
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myUserName/nginx latest a0d6c70867d2 41 seconds ago 578.8 MB
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nginx latest 173c2dd28ab2 3 minutes ago 578.8 MB
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dockerfile/nginx latest 0ade68db1d05 3 weeks ago 578.8 MB
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### Building our own images
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You can build your own images using a `Dockerfile` and the `docker
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build` command. The `Dockerfile` is very flexible and provides a
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powerful set of instructions for building applications into Docker
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images. To learn more about the `Dockerfile` see the [`Dockerfile`
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Reference](/reference/builder/) and [tutorial](https://www.docker.io/learn/dockerfile/).
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## Working with containers
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### Docker Containers
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Docker containers run your applications and are built from Docker
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images. In order to create or start a container, you need an image. This
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could be the base `ubuntu` image or an image built and shared with you
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or an image you've built yourself.
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### Running a new container from an image
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The easiest way to create a new container is to *run* one from an image
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using the `docker run` command.
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# Usage: [sudo] docker run [arguments] ..
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# Example:
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$ docker run -d --name nginx_web nginx /usr/sbin/nginx
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25137497b2749e226dd08f84a17e4b2be114ddf4ada04125f130ebfe0f1a03d3
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This will create a new container from an image called `nginx` which will
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launch the command `/usr/sbin/nginx` when the container is run. We've
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also given our container a name, `nginx_web`. When the container is run
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Docker will return a container ID, a long string that uniquely
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identifies our container. We use can the container's name or its string
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to work with it.
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Containers can be run in two modes:
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* Interactive;
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* Daemonized;
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An interactive container runs in the foreground and you can connect to
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it and interact with it, for example sign into a shell on that
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container. A daemonized container runs in the background.
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A container will run as long as the process you have launched inside it
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is running, for example if the `/usr/bin/nginx` process stops running
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the container will also stop.
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### Listing containers
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We can see a list of all the containers on our host using the `docker
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ps` command. By default the `docker ps` command only shows running
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containers. But we can also add the `-a` flag to show *all* containers:
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both running and stopped.
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# Usage: [sudo] docker ps [-a]
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# Example:
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$ docker ps
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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842a50a13032 $ dockerfile/nginx:latest nginx 35 minutes ago Up 30 minutes 0.0.0.0:80->80/tcp nginx_web
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### Stopping a container
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You can use the `docker stop` command to stop an active container. This
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will gracefully end the active process.
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# Usage: [sudo] docker stop [container ID]
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# Example:
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$ docker stop nginx_web
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nginx_web
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If the `docker stop` command succeeds it will return the name of
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the container it has stopped.
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> **Note:**
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> If you want you to more aggressively stop a container you can use the
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> `docker kill` command.
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### Starting a Container
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Stopped containers can be started again.
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# Usage: [sudo] docker start [container ID]
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# Example:
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$ docker start nginx_web
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nginx_web
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If the `docker start` command succeeds it will return the name of the
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freshly started container.
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## Next steps
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Here we've learned the basics of how to interact with Docker images and
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how to run and work with our first container.
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### Understanding Docker
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Visit [Understanding Docker](understanding-docker.md).
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### Installing Docker
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Visit the [installation](/installation/#installation) section.
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### Get the whole story
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[https://www.docker.io/the_whole_story/](https://www.docker.io/the_whole_story/)
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