mirror of https://github.com/docker/docs.git
246 lines
8.3 KiB
Markdown
246 lines
8.3 KiB
Markdown
---
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description: Instructions for installing Docker on CentOS
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keywords: Docker, Docker documentation, requirements, apt, installation, centos, rpm, install, uninstall, upgrade, update
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redirect_from:
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- /engine/installation/centos/
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title: Get Docker for CentOS
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---
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To get started with Docker on CentOS, make sure you
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[meet the prerequisites](#prerequisites), then
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[install Docker](#install-docker).
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## Prerequisites
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### OS requirements
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To install Docker, you need the 64-bit version of CentOS 7.
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### Remove unofficial Docker packages
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Red Hat's operating system repositories contain an older version of Docker, with
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the package name `docker` instead of `docker-engine`. If you installed this
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version of Docker, remove it using the following command:
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```bash
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$ sudo yum -y remove docker
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```
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The contents of `/var/lib/docker` are not removed, so any images, containers,
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or volumes you created using the older version of Docker are preserved.
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## Install Docker
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You can install Docker in different ways, depending on your needs:
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- Most users
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[set up Docker's repositories](#install-using-the-repository) and install
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from them, for ease of installation and upgrade tasks. This is the
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recommended approach.
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- Some users download the RPM package and install it manually and manage
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upgrades completely manually.
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- Some users cannot use third-party repositories, and must rely on the version
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of Docker in the CentOS repositories. This version of Docker may be out of
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date. Those users should consult the CentOS documentation and not follow these
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procedures.
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### Install using the repository
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Before you install Docker for the first time on a new host machine, you need to
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set up the Docker repository. Afterward, you can install, update, or downgrade
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Docker from the repository.
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#### Set up the repository
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1. Install `yum-utils`, which provides the `yum-config-manager` utility:
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```bash
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$ sudo yum install -y yum-utils
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```
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2. Use the following command to set up the **stable** repository:
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```bash
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$ sudo yum-config-manager \
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--add-repo \
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https://docs.docker.com/engine/installation/linux/repo_files/centos/docker.repo
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```
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3. **Optional**: Enable the **testing** repository. This repository is included
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in the `docker.repo` file above but is disabled by default. You can enable
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it alongside the stable repository. Do not use unstable repositories on
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on production systems or for non-testing workloads.
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> **Warning**: If you have both stable and unstable repositories enabled,
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> installing or updating without specifying a version in the `yum install`
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> or `yum update` command will always install the highest possible version,
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> which will almost certainly be an unstable one.
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```bash
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$ sudo yum-config-manager --enable docker-testing
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```
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You can disable the `testing` repository by running the `yum-config-manager`
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command with the `--disable` flag. To re-enable it, use the
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`--enable` flag. The following command disables the `testing`
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repository.
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```bash
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$ sudo yum-config-manager --disable docker-testing
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```
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#### Install Docker
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1. Update the `yum` package index.
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```bash
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$ sudo yum makecache fast
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```
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If this is the first time you have refreshed the package index since adding
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the Docker repositories, you will be prompted to accept the GPG key, and
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the key's fingerprint will be shown. Verify that the fingerprint matches
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`58118E89F3A912897C070ADBF76221572C52609D` and if so, accept the key.
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2. Install the latest version of Docker, or go to the next step to install a
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specific version.
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```bash
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$ sudo yum -y install docker-engine
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```
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> **Warning**: If you have both stable and unstable repositories enabled,
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> installing or updating Docker without specifying a version in the
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> `yum install` or `yum upgrade` command will always install the highest
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> available version, which will almost certainly be an unstable one.
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3. On production systems, you should install a specific version of Docker
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instead of always using the latest. List the available versions. This
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example uses the `sort -r` command to sort the results by version number,
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highest to lowest, and is truncated.
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> **Note**: This `yum list` command only shows binary packages. To show
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> source packages as well, omit the `.x86_64` from the package name.
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```bash
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$ yum list docker-engine.x86_64 --showduplicates |sort -r
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docker-engine.x86_64 1.13.0-1.el7 docker-main
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docker-engine.x86_64 1.12.5-1.el7 docker-main
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docker-engine.x86_64 1.12.4-1.el7 docker-main
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docker-engine.x86_64 1.12.3-1.el7 docker-main
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```
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The contents of the list depend upon which repositories are enabled, and
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will be specific to your version of CentOS (indicated by the `.el7` suffix
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on the version, in this example). Choose a specific version to install. The
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second column is the version string. The third column is the repository
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name, which indicates which repository the package is from and by extension
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its stability level. To install a specific version, append the version
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string to the package name and separate them by a hyphen (`-`):
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```bash
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$ sudo yum -y install docker-engine-<VERSION_STRING>
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```
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4. Start Docker.
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```bash
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$ sudo systemctl docker start
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```
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5. Verify that `docker` is installed correctly by running the `hello-world`
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image.
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```bash
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$ sudo docker run hello-world
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```
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This command downloads a test image and runs it in a container. When the
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container runs, it prints an informational message and exits.
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Docker is installed and running. You need to use `sudo` to run Docker commands.
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Continue to [Linux postinstall](linux-postinstall.md) to allow non-privileged
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users to run Docker commands and for other optional configuration steps.
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#### Upgrade Docker
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To upgrade Docker, first run `sudo yum makecache fast`, then follow the
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[installation instructions](#install-docker), choosing the new version you want
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to install.
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### Install from a package
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If you cannot use Docker's repository to install Docker, you can download the
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`.rpm` file for your release and install it manually. You will need to download
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a new file each time you want to upgrade Docker.
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1. Go to [https://yum.dockerproject.org/repo/main/centos/](https://yum.dockerproject.org/repo/main/centos/)
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and choose the subdirectory for your CentOS version. Download the `.rpm` file
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for the Docker version you want to install.
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> **Note**: To install a testing version, change the word `stable` in the
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> URL to `testing`. Do not use unstable versions of Docker in production
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> or for non-testing workloads.
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2. Install Docker, changing the path below to the path where you downloaded
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the Docker package.
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```bash
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$ sudo yum -y install /path/to/package.rpm
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```
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3. Start Docker.
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```bash
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$ sudo systemctl docker start
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```
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4. Verify that `docker` is installed correctly by running the `hello-world`
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image.
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```bash
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$ sudo docker run hello-world
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```
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This command downloads a test image and runs it in a container. When the
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container runs, it prints an informational message and exits.
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Docker is installed and running. You need to use `sudo` to run Docker commands.
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Continue to [Post-installation steps for Linux](linux-postinstall.md) to allow
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non-privileged users to run Docker commands and for other optional configuration
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steps.
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#### Upgrade Docker
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To upgrade Docker, download the newer package file and repeat the
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[installation procedure](#install-from-a-package), using `yum -y upgrade`
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instead of `yum -y install`, and pointing to the new file.
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## Uninstall Docker
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1. Uninstall the Docker package:
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```bash
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$ sudo yum -y remove docker-engine
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```
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2. Images, containers, volumes, or customized configuration files on your host
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are not automatically removed. To delete all images, containers, and
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volumes:
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```bash
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$ sudo rm -rf /var/lib/docker
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```
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You must delete any edited configuration files manually.
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## Next steps
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- Continue to [Post-installation steps for Linux](linux-postinstall.md)
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- Continue with the [User Guide](../../userguide/index.md).
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