+Server side U2F configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To allow users to use 'U2F' authentication, the server needs to have a valid
+domain with a valid https certificate. Initially an 'AppId'
+footnote:[AppId https://developers.yubico.com/U2F/App_ID.html]
+needs to be configured.
+
+NOTE: Changing the 'AppId' will render all existing 'U2F' registrations
+unusable!
+
+This is done via `/etc/pve/datacenter.cfg`, for instance:
+
+----
+u2f: appid=https://mypve.example.com:8006
+----
+
+For a single node, the 'AppId' can simply be the web UI address exactly as it
+is used in the browser, including the 'https://' and the port as shown above.
+Please note that some browsers may be more strict than others when matching
+'AppIds'.
+
+When using multiple nodes, it is best to have a separate `https` server
+providing an `appid.json`
+footnote:[Multi-facet apps: https://developers.yubico.com/U2F/App_ID.html]
+file, as it seems to be compatible with most
+browsers. If all nodes use subdomains of the same top level domain, it may be
+enough to use the TLD as 'AppId', but note that some browsers may not accept
+this.
+
+NOTE: A bad 'AppId' will usually produce an error, but we have encountered
+situation where this does not happen, particularly when using a top level domain
+'AppId' for a node accessed via a subdomain in Chromium. For this reason it is
+recommended to test the configuration with multiple browsers, as changing the
+'AppId' later will render existing 'U2F' registrations unusable.
+
+[[pveum_user_configured_u2f]]
+Activating U2F as a user
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+To enable 'U2F' authentication, open the 'TFA' window's 'U2F' tab, type in the
+current password (unless logged in as root), and press the 'Register' button.
+If the server is setup correctly and the browser accepted the server's provided
+'AppId', a message will appear prompting the user to press the button on the
+'U2F' device (if it is a 'YubiKey' the button light should be toggling off and
+on steadily around twice per second).
+
+Firefox users may need to enable 'security.webauth.u2f' via 'about:config'
+before they can use a 'U2F' token.
+
+[[pveum_permission_management]]
+Permission Management
+---------------------
+
+In order for a user to perform an action (such as listing, modifying or
+deleting a parts of a VM configuration), the user needs to have the
+appropriate permissions.
+
+{pve} uses a role and path based permission management system. An entry in
+the permissions table allows a user or group to take on a specific role
+when accessing an 'object' or 'path'. This means an such an access rule can
+be represented as a triple of '(path, user, role)' or '(path, group,
+role)', with the role containing a set of allowed actions, and the path
+representing the target of these actions.
+
+
+[[pveum_roles]]
+Roles
+~~~~~
+
+A role is simply a list of privileges. Proxmox VE comes with a number
+of predefined roles which satisfies most needs.
+
+* `Administrator`: has all privileges
+* `NoAccess`: has no privileges (used to forbid access)
+* `PVEAdmin`: can do most things, but miss rights to modify system settings (`Sys.PowerMgmt`, `Sys.Modify`, `Realm.Allocate`).
+* `PVEAuditor`: read only access
+* `PVEDatastoreAdmin`: create and allocate backup space and templates
+* `PVEDatastoreUser`: allocate backup space and view storage
+* `PVEPoolAdmin`: allocate pools
+* `PVESysAdmin`: User ACLs, audit, system console and system logs
+* `PVETemplateUser`: view and clone templates
+* `PVEUserAdmin`: user administration
+* `PVEVMAdmin`: fully administer VMs
+* `PVEVMUser`: view, backup, config CDROM, VM console, VM power management
+
+You can see the whole set of predefined roles on the GUI.
+
+Adding new roles can be done via both GUI and the command line.