pveum: better LDAP/AD explanation + restructuring

Begin "Authentication Realms" section with brief introduction to each
realm (this was there already, but inconsistent in the level of detail
given for each part).

Give each realm type its own subsection

Adds some more information on LDAP and Active Directory configuration.

Restructure the document to bring the "Syncing LDAP-Based Realms" section
closer to the LDAP and AD sections.

Explain LDAP parameters/options individually in list format

Remove some non-relevant information such as how to add system users

Some more minor langauge and formatting fixup
This commit is contained in:
Dylan Whyte 2021-10-01 17:30:51 +02:00 committed by Thomas Lamprecht
parent a13a971d00
commit 78000a6439

View File

@ -127,39 +127,78 @@ As {pve} users are just counterparts for users existing on some external
realm, the realms have to be configured in `/etc/pve/domains.cfg`.
The following realms (authentication methods) are available:
Linux PAM standard authentication::
In this case, a system user must exist (for example, created via the `adduser`
command) on each node which the user is allowed to log in, and the user
authenticates with their usual system password.
+
[source,bash]
----
useradd heinz
passwd heinz
groupadd watchman
usermod -a -G watchman heinz
----
Linux PAM Standard Authentication::
Proxmox VE authentication server::
This is a Unix-like password store (`/etc/pve/priv/shadow.cfg`).
Passwords are encrypted using the SHA-256 hashing algorithm.
This is the most convenient method for small-scale (or even mid-scale)
installations, where users do not need access to anything outside of
{pve}. In this case, users are fully managed by {pve} and are able to
change their own passwords via the GUI.
Linux PAM is a framework for system-wide user authentication. These users are
created on the host system with commands such as `adduser`. If PAM users exist
on the {pve} host system, corresponding entries can be added to {pve}, to allow
these users to log in via their system username and password.
{pve} Authentication Server::
This is a Unix-like password store, which stores hashed passwords in
`/etc/pve/priv/shadow.cfg`. Passwords are hashed using the SHA-256 hashing
algorithm. This is the most convenient realm for small-scale (or even
mid-scale) installations, where users do not need access to anything outside of
{pve}. In this case, users are fully managed by {pve} and are able to change
their own passwords via the GUI.
LDAP::
It is possible to authenticate users via an LDAP server (for example,
openldap). A server and optional fallback server can be
configured, and the connection can be encrypted via SSL.
+
Users are searched under a 'Base Domain Name' (`base_dn`), with the
username found in the attribute specified in the 'User Attribute Name'
LDAP (Lightweight Directory Access Protocol) is an open, cross-platform protocol
for authentication using directory services. OpenLDAP is a popular open-source
implementations of the LDAP protocol.
Microsoft Active Directory (AD)::
Microsoft Active Directory (AD) is a directory service for Windows domain
networks and is supported as an authentication realm for {pve}. It supports LDAP
as an authentication protocol.
OpenID Connect::
OpenID Connect is implemented as an identity layer on top of the OATH 2.0
protocol. It allows clients to verify the identity of the user, based on
authentication performed by an external authorization server.
Linux PAM Standard Authentication
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As Linux PAM corresponds to host system users, a system user must exist on each
node which the user is allowed to log in on. The user authenticates with their
usual system password. This realm is added by default and can't be removed. In
terms of configurability, an administrator can choose to require two-factor
authentication with logins from the realm and to set the realm as the default
authentication realm.
{pve} Authentication Server
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The {pve} authentication server realm is a simple Unix-like password store.
The realm is created by default, and as with Linux PAM, the only configuration
items available are the ability to require two-factor authentication for users
of the realm, and to set it as the default realm for login.
Unlike the other {pve} realm types, users are created and authenticated entirely
through {pve}, rather than authenticating against another system. Hence, you are
required to set a password for this type of user upon creation.
LDAP
~~~~
You can also use an external LDAP server for user authentication (for examle,
OpenLDAP). In this realm type, users are searched under a 'Base Domain Name'
(`base_dn`), using the username attribute specified in the 'User Attribute Name'
(`user_attr`) field.
+
For instance, if a user is represented via the
following LDIF dataset:
+
A server and optional fallback server can be configured, and the connection can
be encrypted via SSL. Furthermore, filters can be configured for directories and
groups. Filters allow you to further limit the scope of the realm.
For instance, if a user is represented via the following LDIF dataset:
----
# user1 of People at ldap-test.com
dn: uid=user1,ou=People,dc=ldap-test,dc=com
@ -172,33 +211,160 @@ cn: Test User 1
sn: Testers
description: This is the first test user.
----
+
The 'Base Domain Name' would be `ou=People,dc=ldap-test,dc=com` and the user
attribute would be `uid`.
+
If {pve} needs to authenticate (bind) to the LDAP server before being
able to query and authenticate users, a bind domain name can be
configured via the `bind_dn` property in `/etc/pve/domains.cfg`. Its
password then has to be stored in `/etc/pve/priv/ldap/<realmname>.pw`
(for example, `/etc/pve/priv/ldap/my-ldap.pw`). This file should contain a
single line with the raw password.
+
To verify certificates, you need to set `capath`. You can set it either
directly to the CA certificate of your LDAP server, or to the system path
containing all trusted CA certificates (`/etc/ssl/certs`).
Additionally, you need to set the `verify` option, which can also be done over
the web interface.
The main configuration options for an LDAP server realm are as follows:
* `Realm` (`realm`): The realm identifier for {pve} users
* `Base Domain Name` (`base_dn`): The directory which users are searched under
* `User Attribute Name` (`user_attr`): The LDAP attribute containing the
username that users will log in with
* `Server` (`server1`): The server hosting the LDAP directory
* `Fallback Server` (`server2`): An optional fallback server address, in case
the primary server is unreachable
* `Port` (`port`): The port that the LDAP server listens on
NOTE: In order to allow a particular user to authenticate using the LDAP server,
you must also add them as a user of that realm from the {pve} server.
you must also add them as a user of that realm from the {pve} server. This can
be carried out automatically with <<pveum_ldap_sync, syncing>>.
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::
Microsoft Active Directory (AD)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
OpenID Connect allows clients to verify the identity of the user, based on
authentication performed by an external authorization server.
To set up Microsoft AD as a realm, a server address and authentication domain
need to be specified. Active Directory supports most of the same properties as
LDAP, such as an optional fallback server, port, and SSL encryption.
Furthermore, users can be added to {pve} automatically via
<<pveum_ldap_sync, sync>> operations, after configuration.
As with LDAP, if {pve} needs to authenticate before it binds to the AD server,
you must configure the 'Bind User' (`bind_dn`) property. This property is
typically required by default for Microsoft AD.
The main configuration settings for Microsoft Active Directory are:
* `Realm` (`realm`): The realm identifier for {pve} users
* `Domain` (`domain`): The AD domain of the server
* `Server` (`server1`): The FQDN or IP address of the server
* `Fallback Server` (`server2`): An optional fallback server address, in case
the primary server is unreachable
* `Port` (`port`): The port that the Microsoft AD server listens on
[[pveum_ldap_sync]]
Syncing LDAP-Based Realms
~~~~~~~~~~~~~~~~~~~~~~~~~
[thumbnail="screenshot/gui-datacenter-realm-add-ldap.png"]
It's possible to automatically sync users and groups for LDAP-based realms (LDAP
& Microsoft Active Directory), rather than having to add them to {pve} manually.
You can access the sync options from the Add/Edit window of the web interface's
`Authentication` panel or via the `pveum realm add/modify` commands. You can
then carry out the sync operation from the `Authentication` panel of the GUI or
using the following command:
----
pveum realm sync <realm>
----
Users and groups are synced to the cluster-wide configuration file,
`/etc/pve/user.cfg`.
Sync Configuration
^^^^^^^^^^^^^^^^^^
The configuration options for syncing LDAP-based realms can be found in the
`Sync Options` tab of the Add/Edit window.
The configuration options are as follows:
* `Bind User` (`bind_dn`): Refers to the LDAP account used to query users
and groups. This account needs access to all desired entries. If it's set, the
search will be carried out via binding; otherwise, the search will be carried
out anonymously. The user must be a complete LDAP formatted distinguished name
(DN), for example, `cn=admin,dc=example,dc=com`.
* Groupname attr. (group_name_attr): Represents the
users' groups. Only entries which adhere to the usual character limitations of
the `user.cfg` are synced. Groups are synced with `-$realm` attached to the
name, in order to avoid naming conflicts. Please ensure that a sync does not
overwrite manually created groups.
* `User classes` (`user_classes`): Objects classes associated with users.
* `Group classes` (`group_classes`): Objects classes associated with groups.
* `E-Mail attribute`: If the LDAP-based server specifies user email addresses,
these can also be included in the sync by setting the associated attribute
here. From the command line, this is achievable through the
`--sync_attributes` parameter.
* `User Filter` (`filter`): For further filter options to target specific users.
* `Group Filter` (`group_filter`): For further filter options to target specific
groups.
NOTE: Filters allow you to create a set of additional match criteria, to narrow
down the scope of a sync. Information on available LDAP filter types and their
usage can be found at https://ldap.com/ldap-filters/[ldap.com].
[[pveum_ldap_sync_options]]
Sync Options
^^^^^^^^^^^^
[thumbnail="screenshot/gui-datacenter-realm-add-ldap-sync-options.png"]
In addition to the options specified in the previous section, you can also
configure further options that describe the behavior of the sync operation.
These options are either set as parameters before the sync, or as defaults via
the realm option `sync-defaults-options`.
The main options for syncing are:
* `Scope` (`scope`): The scope of what to sync. It can be either `users`,
`groups` or `both`.
* `Enable new` (`enable-new`): If set, the newly synced users are enabled and
can log in. The default is `true`.
* `Full` (`full`): If set, the sync uses the LDAP directory as a source of
truth, overwriting information set manually in the `user.cfg` and deleting
users and groups which are not present in the LDAP directory. If not set, only
new data is written to the configuration, and no stale users are deleted.
* `Purge ACLs` (`purge`): If set, sync removes all corresponding ACLs when
removing users and groups. This is only useful with the option `full`.
* `Preview` (`dry-run`): No data is written to the config. This is useful if you
want to see which users and groups would get synced to the `user.cfg`.
[[pveum_openid]]
@ -207,25 +373,26 @@ 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 automatically configure
* `Issuer URL` (`issuer-url`): This is the URL of the authorization server.
Proxmox uses the OpenID Connect Discovery protocol to automatically 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.
* `Realm` (`realm`): The realm identifier for {pve} users
* `client-key`: Optional OpenID Client Key.
* `Client ID` (`client-id`): OpenID Client ID.
* `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.
* `Client Key` (`client-key`): Optional OpenID Client Key.
* `username-claim`: OpenID claim used to generate the unique username
(`subject`, `username` or `email`).
* `Autocreate Users` (`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` (`username-claim`): OpenID claim used to generate the unique
username (`subject`, `username` or `email`).
Username mapping
^^^^^^^^^^^^^^^^
@ -280,65 +447,6 @@ WARNING: You need to ensure that the user is not allowed to edit
the username setting themselves (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
following CLI command:
----
pveum realm sync <realm>
----
or 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 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, in order to avoid naming
conflicts. Please ensure that a sync does not overwrite manually created
groups.
[[pveum_ldap_sync_options]]
Options
^^^^^^^
[thumbnail="screenshot/gui-datacenter-realm-add-ldap-sync-options.png"]
The main options for syncing are:
* `dry-run`: No data is written to the config. This is useful if you want to
see which users and groups would get synced to the `user.cfg`. This is set
when you click `Preview` in the GUI.
* `enable-new`: If set, the newly synced users are enabled and can log in.
The default is `true`.
* `full`: If set, the sync uses the LDAP directory as a source of truth,
overwriting information set manually in the `user.cfg` and deleting users
and groups which are not present in the LDAP directory. If not set,
only new data is written to the config, and no stale users are deleted.
* `purge`: If set, sync removes all corresponding ACLs when removing users
and groups. This is only useful with the option `full`.
* `scope`: The scope of what to sync. It can be either `users`, `groups` or
`both`.
These options are either set as parameters or as defaults via the
realm option `sync-defaults-options`.
[[pveum_tfa_auth]]
Two-Factor Authentication
-------------------------