docker login

内容説明

Authenticate to a registry.

You can authenticate to any public or private registry for which you have credentials. Authentication may be required for pulling and pushing images. Other commands, such as docker scout and docker build, may also require authentication to access subscription-only features or data related to your Docker organization.

Authentication credentials are stored in the configured credential store. If you use Docker Desktop, credentials are automatically saved to the native keychain of your operating system. If you're not using Docker Desktop, you can configure the credential store in the Docker configuration file, which is located at $HOME/.docker/config.json on Linux or %USERPROFILE%/.docker/config.json on Windows. If you don't configure a credential store, Docker stores credentials in the config.json file in a base64-encoded format. This method is less secure than configuring and using a credential store.

docker login also supports credential helpers to help you handle credentials for specific registries.

Authentication methods

You can authenticate to a registry using a username and access token or password. Docker Hub also supports a web-based sign-in flow, which signs you in to your Docker account without entering your password. For Docker Hub, the docker login command uses a device code flow by default, unless the --username flag is specified. The device code flow is a secure way to sign in. See Authenticate to Docker Hub using device code.

Credential stores

The Docker Engine can keep user credentials in an external credential store, such as the native keychain of the operating system. Using an external store is more secure than storing credentials in the Docker configuration file.

To use a credential store, you need an external helper program to interact with a specific keychain or external store. Docker requires the helper program to be in the client's host $PATH.

You can download the helpers from the docker-credential-helpers releases page. Helpers are available for the following credential stores:

• D-Bus Secret Service
• Apple macOS keychain
• Microsoft Windows Credential Manager
• pass

With Docker Desktop, the credential store is already installed and configured for you. Unless you want to change the credential store used by Docker Desktop, you can skip the following steps.

Configure the credential store

You need to specify the credential store in $HOME/.docker/config.json to tell the Docker Engine to use it. The value of the config property should be the suffix of the program to use (i.e. everything after docker-credential-). For example, to use docker-credential-osxkeychain:

{
  "credsStore": "osxkeychain"
}

If you are currently logged in, run docker logout to remove the credentials from the file and run docker login again.

Default behavior

By default, Docker looks for the native binary on each of the platforms, i.e. osxkeychain on macOS, wincred on Windows, and pass on Linux. A special case is that on Linux, Docker will fall back to the secretservice binary if it cannot find the pass binary. If none of these binaries are present, it stores the base64-encoded credentials in the config.json configuration file.

Credential helper protocol

Credential helpers can be any program or script that implements the credential helper protocol. This protocol is inspired by Git, but differs in the information shared.

The helpers always use the first argument in the command to identify the action. There are only three possible values for that argument: store, get, and erase.

The store command takes a JSON payload from the standard input. That payload carries the server address, to identify the credential, the username, and either a password or an identity token.

{
  "ServerURL": "https://index.docker.io/v1",
  "Username": "david",
  "Secret": "passw0rd1"
}

If the secret being stored is an identity token, the Username should be set to <token>.

The store command can write error messages to STDOUT that the Docker Engine will show if there was an issue.

The get command takes a string payload from the standard input. That payload carries the server address that the Docker Engine needs credentials for. This is an example of that payload: https://index.docker.io/v1.

The get command writes a JSON payload to STDOUT. Docker reads the user name and password from this payload:

{
  "Username": "david",
  "Secret": "passw0rd1"
}

The erase command takes a string payload from STDIN. That payload carries the server address that the Docker Engine wants to remove credentials for. This is an example of that payload: https://index.docker.io/v1.

The erase command can write error messages to STDOUT that the Docker Engine will show if there was an issue.

Credential helpers

Credential helpers are similar to credential stores, but act as the designated programs to handle credentials for specific registries. The default credential store will not be used for operations concerning credentials of the specified registries.

Configure credential helpers

If you are currently logged in, run docker logout to remove the credentials from the default store.

Credential helpers are specified in a similar way to credsStore, but allow for multiple helpers to be configured at a time. Keys specify the registry domain, and values specify the suffix of the program to use (i.e. everything after docker-credential-). For example:

{
  "credHelpers": {
    "myregistry.example.com": "secretservice",
    "docker.internal.example": "pass",
  }
}

オプション

利用例

Authenticate to Docker Hub with web-based login

By default, the docker login command authenticates to Docker Hub, using a device code flow. This flow lets you authenticate to Docker Hub without entering your password. Instead, you visit a URL in your web browser, enter a code, and authenticate.

$ docker login

USING WEB-BASED LOGIN
To sign in with credentials on the command line, use 'docker login -u <username>'

Your one-time device confirmation code is: LNFR-PGCJ
Press ENTER to open your browser or submit your device code here: https://login.docker.com/activate

Waiting for authentication in the browser…

After entering the code in your browser, you are authenticated to Docker Hub using the account you're currently signed in with on the Docker Hub website or in Docker Desktop. If you aren't signed in, you are prompted to sign in after entering the device code.

Authenticate to a self-hosted registry

If you want to authenticate to a self-hosted registry you can specify this by adding the server name.

$ docker login registry.example.com

By default, the docker login command assumes that the registry listens on port 443 or 80. If the registry listens on a different port, you can specify it by adding the port number to the server name.

$ docker login registry.example.com:1337

メモ

Registry addresses should not include URL path components, only the hostname and (optionally) the port. Registry addresses with URL path components may result in an error. For example, docker login registry.example.com/foo/ is incorrect, while docker login registry.example.com is correct.

The exception to this rule is the Docker Hub registry, which may use the /v1/ path component in the address for historical reasons.

Authenticate to a registry with a username and password

To authenticate to a registry with a username and password, you can use the --username or -u flag. The following example authenticates to Docker Hub with the username moby. The password is entered interactively.

$ docker login -u moby

Provide a password using STDIN (--password-stdin)

To run the docker login command non-interactively, you can set the --password-stdin flag to provide a password through STDIN. Using STDIN prevents the password from ending up in the shell's history, or log-files.

The following example reads a password from a file, and passes it to the docker login command using STDIN:

$ cat ~/my_password.txt | docker login --username foo --password-stdin