github.com/vieux/docker@v0.6.3-0.20161004191708-e097c2a938c7/docs/installation/linux/centos.md (about)

     1  <!--[metadata]>
     2  +++
     3  aliases = [ "/engine/installation/centos/"]
     4  title = "Installation on CentOS"
     5  description = "Instructions for installing Docker on CentOS"
     6  keywords = ["Docker, Docker documentation, requirements, linux, centos, epel, docker.io,  docker-io"]
     7  [menu.main]
     8  parent = "engine_linux"
     9  weight=-4
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    11  <![end-metadata]-->
    12  
    13  # CentOS
    14  
    15  Docker runs on CentOS 7.X. An installation on other binary compatible EL7
    16  distributions such as Scientific Linux might succeed, but Docker does not test
    17  or support Docker on these distributions.
    18  
    19  These instructions install Docker using release packages and installation
    20  mechanisms managed by Docker, to be sure that you get the latest version
    21  of Docker. If you wish to install using CentOS-managed packages, consult
    22  your CentOS release documentation.
    23  
    24  ## Prerequisites
    25  
    26  Docker requires a 64-bit OS and version 3.10 or higher of the Linux kernel.
    27  
    28  To check your current kernel version, open a terminal and use `uname -r` to
    29  display your kernel version:
    30  
    31  ```bash
    32  $ uname -r
    33  3.10.0-229.el7.x86_64
    34  ```
    35  
    36  Finally, it is recommended that you fully update your system. Keep in mind
    37  that your system should be fully patched to fix any potential kernel bugs.
    38  Any reported kernel bugs may have already been fixed on the latest kernel
    39  packages.
    40  
    41  ## Install Docker Engine
    42  
    43  There are two ways to install Docker Engine.  You can [install using the `yum`
    44  package manager](#install-with-yum). Or you can use `curl` with the [`get.docker.com`
    45  site](#install-with-the-script). This second method runs an installation script
    46  which also installs via the `yum` package manager.
    47  
    48  ### Install with yum
    49  
    50  1. Log into your machine as a user with `sudo` or `root` privileges.
    51  
    52  2. Make sure your existing packages are up-to-date.
    53  
    54      ```bash
    55      $ sudo yum update
    56      ```
    57  
    58  3. Add the `yum` repo.
    59  
    60      ```bash
    61      $ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
    62      [dockerrepo]
    63      name=Docker Repository
    64      baseurl=https://yum.dockerproject.org/repo/main/centos/7/
    65      enabled=1
    66      gpgcheck=1
    67      gpgkey=https://yum.dockerproject.org/gpg
    68      EOF
    69      ```
    70  
    71  4. Install the Docker package.
    72  
    73      ```bash
    74      $ sudo yum install docker-engine
    75      ```
    76  
    77  5. Enable the service.
    78  
    79      ```bash
    80      $ sudo systemctl enable docker.service
    81      ```
    82  
    83  6. Start the Docker daemon.
    84  
    85      ```bash
    86      $ sudo systemctl start docker
    87      ```
    88  
    89  7. Verify `docker` is installed correctly by running a test image in a container.
    90  
    91          $ sudo docker run --rm hello-world
    92  
    93          Unable to find image 'hello-world:latest' locally
    94          latest: Pulling from library/hello-world
    95          c04b14da8d14: Pull complete
    96          Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
    97          Status: Downloaded newer image for hello-world:latest
    98  
    99          Hello from Docker!
   100          This message shows that your installation appears to be working correctly.
   101  
   102          To generate this message, Docker took the following steps:
   103           1. The Docker client contacted the Docker daemon.
   104           2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
   105           3. The Docker daemon created a new container from that image which runs the
   106              executable that produces the output you are currently reading.
   107           4. The Docker daemon streamed that output to the Docker client, which sent it
   108              to your terminal.
   109  
   110          To try something more ambitious, you can run an Ubuntu container with:
   111           $ docker run -it ubuntu bash
   112  
   113          Share images, automate workflows, and more with a free Docker Hub account:
   114           https://hub.docker.com
   115  
   116          For more examples and ideas, visit:
   117           https://docs.docker.com/engine/userguide/
   118  
   119  If you need to add an HTTP Proxy, set a different directory or partition for the
   120  Docker runtime files, or make other customizations, read our Systemd article to
   121  learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
   122  
   123  ### Install with the script
   124  
   125  1. Log into your machine as a user with `sudo` or `root` privileges.
   126  
   127  2. Make sure your existing packages are up-to-date.
   128  
   129      ```bash
   130      $ sudo yum update
   131      ```
   132  
   133  3. Run the Docker installation script.
   134  
   135      ```bash
   136      $ curl -fsSL https://get.docker.com/ | sh
   137      ```
   138  
   139      This script adds the `docker.repo` repository and installs Docker.
   140  
   141  4. Enable the service.
   142  
   143      ```bash
   144      $ sudo systemctl enable docker.service
   145      ```
   146  
   147  5. Start the Docker daemon.
   148  
   149      ```bash
   150      $ sudo systemctl start docker
   151      ```
   152  
   153  6. Verify `docker` is installed correctly by running a test image in a container.
   154  
   155      ```bash
   156      $ sudo docker run hello-world
   157      ```
   158  
   159  If you need to add an HTTP Proxy, set a different directory or partition for the
   160  Docker runtime files, or make other customizations, read our Systemd article to
   161  learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
   162  
   163  ## Create a docker group
   164  
   165  The `docker` daemon binds to a Unix socket instead of a TCP port. By default
   166  that Unix socket is owned by the user `root` and other users can access it with
   167  `sudo`. For this reason, `docker` daemon always runs as the `root` user.
   168  
   169  To avoid having to use `sudo` when you use the `docker` command, create a Unix
   170  group called `docker` and add users to it. When the `docker` daemon starts, it
   171  makes the ownership of the Unix socket read/writable by the `docker` group.
   172  
   173  >**Warning**: The `docker` group is equivalent to the `root` user; For details
   174  >on how this impacts security in your system, see [*Docker Daemon Attack
   175  >Surface*](../../security/security.md#docker-daemon-attack-surface) for details.
   176  
   177  To create the `docker` group and add your user:
   178  
   179  1. Log into your machine as a user with `sudo` or `root` privileges.
   180  
   181  2. Create the `docker` group.
   182  
   183      ```bash
   184      $ sudo groupadd docker
   185      ```
   186  
   187  3. Add your user to `docker` group.
   188  
   189      ```bash
   190      $ sudo usermod -aG docker your_username`
   191      ```
   192  
   193  4. Log out and log back in.
   194  
   195      This ensures your user is running with the correct permissions.
   196  
   197  5. Verify that your user is in the docker group by running `docker` without `sudo`.
   198  
   199      ```bash
   200      $ docker run hello-world
   201      ```
   202  
   203  ## Start the docker daemon at boot
   204  
   205  Configure the Docker daemon to start automatically when the host starts:
   206  
   207  ```bash
   208  $ sudo systemctl enable docker
   209  ```
   210  
   211  ## Uninstall
   212  
   213  You can uninstall the Docker software with `yum`.
   214  
   215  1. List the installed Docker packages.
   216  
   217      ```bash
   218      $ yum list installed | grep docker
   219  
   220      docker-engine.x86_64     1.7.1-0.1.el7@/docker-engine-1.7.1-0.1.el7.x86_64
   221      ```
   222  
   223  2. Remove the package.
   224  
   225      ```bash
   226      $ sudo yum -y remove docker-engine.x86_64
   227      ```
   228  
   229  	This command does not remove images, containers, volumes, or user-created
   230  	configuration files on your host.
   231  
   232  3. To delete all images, containers, and volumes, run the following command:
   233  
   234      ```bash
   235      $ rm -rf /var/lib/docker
   236      ```
   237  
   238  4. Locate and delete any user-created configuration files.