github.com/hustcat/docker@v1.3.3-0.20160314103604-901c67a8eeab/docs/reference/commandline/login.md (about)

     1  <!--[metadata]>
     2  +++
     3  title = "login"
     4  description = "The login command description and usage"
     5  keywords = ["registry, login, image"]
     6  [menu.main]
     7  parent = "smn_cli"
     8  +++
     9  <![end-metadata]-->
    10  
    11  # login
    12  
    13      Usage: docker login [OPTIONS] [SERVER]
    14  
    15      Log in to a Docker registry server, if no server is
    16  	specified "https://index.docker.io/v1/" is the default.
    17  
    18        --help               Print usage
    19        -p, --password=""    Password
    20        -u, --username=""    Username
    21  
    22  If you want to login to a self-hosted registry you can specify this by
    23  adding the server name.
    24  
    25      example:
    26      $ docker login localhost:8080
    27  
    28  
    29  `docker login` requires user to use `sudo` or be `root`, except when:
    30  
    31  1.  connecting to a remote daemon, such as a `docker-machine` provisioned `docker engine`.
    32  2.  user is added to the `docker` group.  This will impact the security of your system; the `docker` group is `root` equivalent.  See [Docker Daemon Attack Surface](https://docs.docker.com/security/security/#docker-daemon-attack-surface) for details.
    33  
    34  You can log into any public or private repository for which you have
    35  credentials.  When you log in, the command stores encoded credentials in
    36  `$HOME/.docker/config.json` on Linux or `%USERPROFILE%/.docker/config.json` on Windows.
    37  
    38  > **Note**:  When running `sudo docker login` credentials are saved in `/root/.docker/config.json`.
    39  >
    40  
    41  ## Credentials store
    42  
    43  The Docker Engine can keep user credentials in an external credentials store,
    44  such as the native keychain of the operating system. Using an external store
    45  is more secure than storing credentials in the Docker configuration file.
    46  
    47  To use a credentials store, you need an external helper program to interact
    48  with a specific keychain or external store. Docker requires the helper
    49  program to be in the client's host `$PATH`.
    50  
    51  This is the list of currently available credentials helpers and where
    52  you can download them from:
    53  
    54  - D-Bus Secret Service: https://github.com/docker/docker-credential-helpers/releases
    55  - Apple OS X keychain: https://github.com/docker/docker-credential-helpers/releases
    56  - Microsoft Windows Credential Manager: https://github.com/docker/docker-credential-helpers/releases
    57  
    58  ### Usage
    59  
    60  You need to speficy the credentials store in `$HOME/.docker/config.json`
    61  to tell the docker engine to use it:
    62  
    63  ```json
    64  {
    65  	"credsStore": "osxkeychain"
    66  }
    67  ```
    68  
    69  If you are currently logged in, run `docker logout` to remove
    70  the credentials from the file and run `docker login` again.
    71  
    72  ### Protocol
    73  
    74  Credential helpers can be any program or script that follows a very simple protocol.
    75  This protocol is heavily inspired by Git, but it differs in the information shared.
    76  
    77  The helpers always use the first argument in the command to identify the action.
    78  There are only three possible values for that argument: `store`, `get`, and `erase`.
    79  
    80  The `store` command takes a JSON payload from the standard input. That payload carries
    81  the server address, to identify the credential, the user name and the password.
    82  This is an example of that payload:
    83  
    84  ```json
    85  {
    86  	"ServerURL": "https://index.docker.io/v1",
    87  	"Username": "david",
    88  	"Password": "passw0rd1"
    89  }
    90  ```
    91  
    92  The `store` command can write error messages to `STDOUT` that the docker engine
    93  will show if there was an issue.
    94  
    95  The `get` command takes a string payload from the standard input. That payload carries
    96  the server address that the docker engine needs credentials for. This is
    97  an example of that payload: `https://index.docker.io/v1`.
    98  
    99  The `get` command writes a JSON payload to `STDOUT`. Docker reads the user name
   100  and password from this payload:
   101  
   102  ```json
   103  {
   104  	"Username": "david",
   105  	"Password": "passw0rd1"
   106  }
   107  ```
   108  
   109  The `erase` command takes a string payload from `STDIN`. That payload carries
   110  the server address that the docker engine wants to remove credentials for. This is
   111  an example of that payload: `https://index.docker.io/v1`.
   112  
   113  The `erase` command can write error messages to `STDOUT` that the docker engine
   114  will show if there was an issue.