# Keycloak {#module-services-keycloak}

[Keycloak](https://www.keycloak.org/) is an
open source identity and access management server with support for
[OpenID Connect](https://openid.net/connect/),
[OAUTH 2.0](https://oauth.net/2/) and
[SAML 2.0](https://en.wikipedia.org/wiki/SAML_2.0).

## Administration {#module-services-keycloak-admin}

An administrative user with the username
`admin` is automatically created in the
`master` realm. Its initial password can be
configured by setting [](#opt-services.keycloak.initialAdminPassword)
and defaults to `changeme`. The password is
not stored safely and should be changed immediately in the
admin panel.

Refer to the [Keycloak Server Administration Guide](
  https://www.keycloak.org/docs/latest/server_admin/index.html
) for information on
how to administer your Keycloak
instance.

## Database access {#module-services-keycloak-database}

Keycloak can be used with either PostgreSQL, MariaDB or
MySQL. Which one is used can be
configured in [](#opt-services.keycloak.database.type). The selected
database will automatically be enabled and a database and role
created unless [](#opt-services.keycloak.database.host) is changed
from its default of `localhost` or
[](#opt-services.keycloak.database.createLocally) is set to `false`.

External database access can also be configured by setting
[](#opt-services.keycloak.database.host),
[](#opt-services.keycloak.database.name),
[](#opt-services.keycloak.database.username),
[](#opt-services.keycloak.database.useSSL) and
[](#opt-services.keycloak.database.caCert) as
appropriate. Note that you need to manually create the database
and allow the configured database user full access to it.

[](#opt-services.keycloak.database.passwordFile)
must be set to the path to a file containing the password used
to log in to the database. If [](#opt-services.keycloak.database.host)
and [](#opt-services.keycloak.database.createLocally)
are kept at their defaults, the database role
`keycloak` with that password is provisioned
on the local database instance.

::: {.warning}
The path should be provided as a string, not a Nix path, since Nix
paths are copied into the world readable Nix store.
:::

## Hostname {#module-services-keycloak-hostname}

The hostname is used to build the public URL used as base for
all frontend requests and must be configured through
[](#opt-services.keycloak.settings.hostname).

::: {.note}
If you're migrating an old Wildfly based Keycloak instance
and want to keep compatibility with your current clients,
you'll likely want to set [](#opt-services.keycloak.settings.http-relative-path)
to `/auth`. See the option description
for more details.
:::

[](#opt-services.keycloak.settings.hostname-strict-backchannel)
determines whether Keycloak should force all requests to go
through the frontend URL. By default,
Keycloak allows backend requests to
instead use its local hostname or IP address and may also
advertise it to clients through its OpenID Connect Discovery
endpoint.

For more information on hostname configuration, see the [Hostname
section of the Keycloak Server Installation and Configuration
Guide](https://www.keycloak.org/server/hostname).

## Setting up TLS/SSL {#module-services-keycloak-tls}

By default, Keycloak won't accept
unsecured HTTP connections originating from outside its local
network.

HTTPS support requires a TLS/SSL certificate and a private key,
both [PEM formatted](https://en.wikipedia.org/wiki/Privacy-Enhanced_Mail).
Their paths should be set through
[](#opt-services.keycloak.sslCertificate) and
[](#opt-services.keycloak.sslCertificateKey).

::: {.warning}
 The paths should be provided as a strings, not a Nix paths,
since Nix paths are copied into the world readable Nix store.
:::

## Themes {#module-services-keycloak-themes}

You can package custom themes and make them visible to
Keycloak through [](#opt-services.keycloak.themes). See the
[Themes section of the Keycloak Server Development Guide](
  https://www.keycloak.org/docs/latest/server_development/#_themes
) and the description of the aforementioned NixOS option for
more information.

## Configuration file settings {#module-services-keycloak-settings}

Keycloak server configuration parameters can be set in
[](#opt-services.keycloak.settings). These correspond
directly to options in
{file}`conf/keycloak.conf`. Some of the most
important parameters are documented as suboptions, the rest can
be found in the [All
configuration section of the Keycloak Server Installation and
Configuration Guide](https://www.keycloak.org/server/all-config).

Options containing secret data should be set to an attribute
set containing the attribute `_secret` - a
string pointing to a file containing the value the option
should be set to. See the description of
[](#opt-services.keycloak.settings) for an example.

## Example configuration {#module-services-keycloak-example-config}

A basic configuration with some custom settings could look like this:
```nix
{
  services.keycloak = {
    enable = true;
    settings = {
      hostname = "keycloak.example.com";
      hostname-strict-backchannel = true;
    };
    initialAdminPassword = "e6Wcm0RrtegMEHl";  # change on first login
    sslCertificate = "/run/keys/ssl_cert";
    sslCertificateKey = "/run/keys/ssl_key";
    database.passwordFile = "/run/keys/db_password";
  };
}
```
