+A server and authentication domain need to be specified. Like with LDAP, an
+optional fallback server, port, and SSL encryption can be configured.
+
+OpenId Connect::
+
+OpenID Connect allows clients to verify the identity of the user based
+on the authentication performed by an external authorization
+server.
+
+
+[[pveum_openid]]
+OpenId Connect
+~~~~~~~~~~~~~~
+
+The main OpenID Connect configuration options are:
+
+* `issuer-url`: This is the Url to the authorization server. Proxmox
+uses the OpenID Connect Discovery protocol to automatiocally configure
+further details.
++
+While it is possible to use unencrypted `http://` Urls, we strongly recommend to
+use encrypted `https://` connections.
+
+* `client-id`: OpenID Client ID.
+
+* `client-key`: Optional OpenID Client Key.
+
+* `autocreate`: Automatically create users if they do not exist. While
+authentication is done at the OpenID server, all users still need an
+entry in the {pve} user configuration. You can either add them
+manually, or use the `autocreate` option to automatically add new
+users.
+
+* `username-claim`: OpenID claim used to generate the unique username
+ (`subject`, `username` or `email`).
+
+Username mapping
+^^^^^^^^^^^^^^^^
+
+The Openid Connect specification defines a single unique attribute
+('claim' in OpenId terms) named `subject`. By default, we use the
+value of this attribute to generate {pve} usernames, by simple adding
+`@` and the realm name: `${subject}@${realm}`.
+
+Unfortunately, most OpenID server use random strings for `subject`, like
+`DGH76OKH34BNG3245SB`, so a typical username would look like
+`DGH76OKH34BNG3245SB@yourrealm`. While unique, it is really hard for
+humans to remember such random strings, making it quite impossible to
+associate real users with that.
+
+The `username-claim` setting allows you to use other attributes for
+the username mapping. Setting it to `username` is preferred, if the
+OpenId Connect server provides that attribute and guarantee its
+uniqueness.
+
+Another option is to use `email`, which also yields to human readable
+usernames. Again, only use this setting if the server guarantees the
+uniqueness of this attribute.
+
+Examples
+^^^^^^^^
+
+Here is an example to create an OpenId realm using Google. You need to
+replace `--client-id` and `--client-key` with the values
+from your Google OpenId settings.
+
+----
+pveum realm add myrealm1 --type openid --issuer-url https://accounts.google.com --client-id XXXX --client-key YYYY --username-claim email
+----
+
+Above setup uses `--username-claim email`, so the usernames at the
+{pve} side looks like `example.user@google.com@myrealm1`.
+
+KeyCloak (https://www.keycloak.org/) is a popular Open Source Identity
+and Access Management supporting OpenId Connect. In the following
+example, you need to replace the `--issuer-url` and `--client-id` with
+your setting:
+
+----
+pveum realm add myrealm2 --type openid --issuer-url https://your.server:8080/auth/realms/your-realm --client-id XXX --username-claim username
+----
+
+Using `--username-claim username` yields to simple usernames on the
+{pve} side, like `example.user@myrealm2`.
+
+WARNING: You need to make sure that the user is not allowed to edit
+the username setting himself (on the Keycloak server).
+
+
+[[pveum_ldap_sync]]
+Syncing LDAP-based realms
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+[thumbnail="screenshot/gui-datacenter-realm-add-ldap.png"]
+
+It is possible to sync users and groups for LDAP based realms. You can use the
+CLI command
+
+----
+ pveum realm sync <realm>
+----
+or in the `Authentication` panel of the GUI. Users and groups are synced to the
+cluster-wide user configuration file `/etc/pve/user.cfg`.
+
+Requirements and limitations
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The `bind_dn` is used to query the users and groups. This account needs access
+to all desired entries.
+
+The fields which represent the names of the users and groups can be configured
+via the `user_attr` and `group_name_attr` respectively. Only entries which
+adhere to the usual character limitations of the user.cfg are synced.
+
+Groups are synced with `-$realm` attached to the name, to avoid naming
+conflicts. Please make sure that a sync does not overwrite manually created
+groups.
+
+[[pveum_ldap_sync_options]]
+Options
+^^^^^^^