containers-common/containers-auth.json.5.md

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% containers-auth.json 5
# NAME
containers-auth.json - syntax for the registry authentication file
# DESCRIPTION
A file in JSON format controlling authentication against container image registries.
The primary (read/write) file is stored at `${XDG_RUNTIME_DIR}/containers/auth.json` on Linux;
on Windows and macOS, at `$HOME/.config/containers/auth.json`.
When searching for the credential for a registry, the following files will be read in sequence until the valid credential is found:
first reading the primary (read/write) file, or the explicit override using an option of the calling application.
If credentials are not present there,
the search continues in `${XDG_CONFIG_HOME}/containers/auth.json` (usually `~/.config/containers/auth.json`), `$HOME/.docker/config.json`, `$HOME/.dockercfg`.
Except for the primary (read/write) file, other files are read-only unless the user, using an option of the calling application, explicitly points at it as an override.
## FORMAT
The auth.json file stores, or references, credentials that allow the user to authenticate
to container image registries.
It is primarily managed by a `login` command from a container tool such as `podman login`,
`buildah login`, or `skopeo login`.
Each entry contains a single hostname (e.g., `docker.io`) or a namespace (e.g., `quay.io/user/image`) as a key,
and credentials in the form of a base64-encoded string as value of `auth`. The
base64-encoded string contains a concatenation of the username, a colon, and the
password.
When checking for available credentials, the relevant repository is matched
against available keys in its hierarchical order, going from most-specific to least-specific.
For example, an image pull for `my-registry.local/namespace/user/image:latest` will
result in a lookup in `auth.json` in the following order:
- `my-registry.local/namespace/user/image`
- `my-registry.local/namespace/user`
- `my-registry.local/namespace`
- `my-registry.local`
This way it is possible to setup multiple credentials for a single registry
which can be distinguished by their path.
The following example shows the values found in auth.json after the user logged in to
their accounts on quay.io and docker.io:
```
{
"auths": {
"docker.io": {
"auth": "erfi7sYi89234xJUqaqxgmzcnQ2rRFWM5aJX0EC="
},
"quay.io": {
"auth": "juQAqGmz5eR1ipzx8Evn6KGdw8fEa1w5MWczmgY="
}
}
}
```
This example demonstrates how to use multiple paths for a single registry, while
preserving a fallback for `my-registry.local`:
```
{
"auths": {
"my-registry.local/foo/bar/image": {
"auth": "…"
},
"my-registry.local/foo": {
"auth": "…"
},
"my-registry.local": {
"auth": "…"
},
}
}
```
An entry can be removed by using a `logout` command from a container
tool such as `podman logout` or `buildah logout`.
In addition, credential helpers can be configured for specific registries, and the credentials-helper
software can be used to manage the credentials more securely than storing only base64-encoded credentials in `auth.json`.
When the credential helper is in use on a Linux platform, the auth.json file would contain keys that specify the registry domain, and values that specify the suffix of the program to use (i.e. everything after docker-credential-). For example:
```
{
"auths": {
"localhost:5001": {}
},
"credHelpers": {
"registry.example.com": "secretservice"
}
}
```
For more information on credential helpers, please reference the [GitHub docker-credential-helpers project](https://github.com/docker/docker-credential-helpers/releases).
# SEE ALSO
buildah-login(1), buildah-logout(1), podman-login(1), podman-logout(1), skopeo-login(1), skopeo-logout(1)
# HISTORY
Feb 2020, Originally compiled by Tom Sweeney <tsweeney@redhat.com>