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User Management

Proxmox VE supports multiple authentication sources, e.g. Linux PAM, an integrated Proxmox VE authentication server, LDAP, Microsoft Active Directory.

By using the role based user- and permission management for all objects (VMs, storages, nodes, etc.) granular access can be defined.

Users

{pve} stores user attributes in /etc/pve/user.cfg. Passwords are not stored here, users are instead associated with authentication realms described below. Therefore a user is internally often identified by its name and realm in the form <userid>@<realm>.

Each user entry in this file contains the following information:

  • First name

  • Last name

  • E-mail address

  • Group memberships

  • An optional Expiration date

  • A comment or note about this user

  • Whether this user is enabled or disabled

  • Optional two factor authentication keys

System administrator

The system’s root user can always log in via the Linux PAM realm and is an unconfined administrator. This user cannot be deleted, but attributes can still be changed and system mails will be sent to the email address assigned to this user.

Groups

Each user can be member of several groups. Groups are the preferred way to organize access permissions. You should always grant permission to groups instead of using individual users. That way you will get a much shorter access control list which is easier to handle.

Authentication Realms

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 has to exist (e.g. created via the adduser command) on all nodes the user is allowed to login, and the user authenticates with their usual system password.

useradd heinz
passwd heinz
groupadd watchman
usermod -a -G watchman heinz
Proxmox VE authentication server

This is a unix like password store (/etc/pve/priv/shadow.cfg). Password are encrypted using the SHA-256 hash method. This is the most convenient method for small (or even medium) 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 (e.g. openldap). The server and an 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 user name found in the attribute specified in the User Attribute Name (user_attr) field.

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
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: inetOrgPerson
uid: user1
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 (e.g. /etc/pve/priv/ldap/my-ldap.pw). This file should contain a single line containing the raw password.

Microsoft Active Directory

A server and authentication domain need to be specified. Like with ldap an optional fallback server, optional port, and SSL encryption can be configured.

Two factor authentication

There are two ways to use two factor authentication:

It can be required by the authentication realm, either via TOTP or YubiKey OTP. In this case a newly created user needs their keys added immediately as there is no way to log in without the second factor. In the case of TOTP a user can also change the TOTP later on provided they can log in first.

Alternatively a user can choose to opt into two factor authentication via TOTP later on even if the realm does not enforce it. As another option, if the server has an AppId configured, a user can opt into U2F authentication, provided the realm does not enforce any other second factor.

Realm enforced two factor authentication

This can be done by selecting one of the available methods via the TFA dropdown box when adding or editing an Authentication Realm. When a realm has TFA enabled it becomes a requirement and only users with configured TFA will be able to login.

Currently there are two methods available:

Time based OATH (TOTP)

This uses the standard HMAC-SHA1 algorithm where the current time is hashed with the user’s configured key. The time step and password length parameters are configured.

A user can have multiple keys configured (separated by spaces), and the keys can be specified in Base32 (RFC3548) or hexadecimal notation.

{pve} provides a key generation tool (oathkeygen) which prints out a random key in Base32 notation which can be used directly with various OTP tools, such as the oathtool command line tool, the Google authenticator or FreeOTP Android apps.

YubiKey OTP

For authenticating via a YubiKey a Yubico API ID, API KEY and validation server URL must be configured, and users must have a YubiKey available. In order to get the key ID from a YubiKey, you can trigger the YubiKey once after connecting it to USB and copy the first 12 characters of the typed password into the user’s Key IDs field.

Please refer to the YubiKey OTP documentation for how to use the YubiCloud or host your own verification server.

User configured TOTP authentication

A user can choose to use TOTP as a second factor on login via the TFA button in the user list, unless the realm enforces YubiKey OTP.

After opening the TFA window, the user is presented with a dialog to setup TOTP authentication. The Secret field contains the key, which can simply be generated randomly via the Randomize button. An optional Issuer Name can be added to provide information to the TOTP app what the key belongs to. Most TOTP apps will show the issuer name together with the corresponding OTP values. The user name is also included in the QR code for the TOTP app.

After generating a key, a QR code will be displayed which can be used with most OTP apps such as FreeOTP. Now the user needs to verify both the current user password (unless logged in as root), as well as the ability to correctly use the TOTP key by typing the current OTP value into the Verification Code field before pressing the Apply button.

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 [1] 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 [2] 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.

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.

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.

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.

For the GUI just navigate to Permissions → User Tab from Datacenter and click on the Create button, there you can set a name and select all desired roles from the Privileges dropdown box.

To add a role through the command line you can use the pveum CLI tool, like this:

pveum roleadd PVE_Power-only -privs "VM.PowerMgmt VM.Console"
pveum roleadd Sys_Power-only -privs "Sys.PowerMgmt Sys.Console"

Privileges

A privilege is the right to perform a specific action. To simplify management, lists of privileges are grouped into roles, which can then be used in the permission table. Note that privileges cannot directly be assigned to users and paths without being part of a role.

We currently use the following privileges:

Node / System related privileges

  • Permissions.Modify: modify access permissions

  • Sys.PowerMgmt: Node power management (start, stop, reset, shutdown, …​)

  • Sys.Console: console access to Node

  • Sys.Syslog: view Syslog

  • Sys.Audit: view node status/config, Corosync cluster config and HA config

  • Sys.Modify: create/remove/modify node network parameters

  • Group.Allocate: create/remove/modify groups

  • Pool.Allocate: create/remove/modify a pool

  • Realm.Allocate: create/remove/modify authentication realms

  • Realm.AllocateUser: assign user to a realm

  • User.Modify: create/remove/modify user access and details.

Virtual machine related privileges

  • VM.Allocate: create/remove new VM to server inventory

  • VM.Migrate: migrate VM to alternate server on cluster

  • VM.PowerMgmt: power management (start, stop, reset, shutdown, …​)

  • VM.Console: console access to VM

  • VM.Monitor: access to VM monitor (kvm)

  • VM.Backup: backup/restore VMs

  • VM.Audit: view VM config

  • VM.Clone: clone/copy a VM

  • VM.Config.Disk: add/modify/delete Disks

  • VM.Config.CDROM: eject/change CDROM

  • VM.Config.CPU: modify CPU settings

  • VM.Config.Memory: modify Memory settings

  • VM.Config.Network: add/modify/delete Network devices

  • VM.Config.HWType: modify emulated HW type

  • VM.Config.Options: modify any other VM configuration

  • VM.Snapshot: create/remove VM snapshots

Storage related privileges

  • Datastore.Allocate: create/remove/modify a data store, delete volumes

  • Datastore.AllocateSpace: allocate space on a datastore

  • Datastore.AllocateTemplate: allocate/upload templates and iso images

  • Datastore.Audit: view/browse a datastore

Objects and Paths

Access permissions are assigned to objects, such as a virtual machines, storages or pools of resources. We use file system like paths to address these objects. These paths form a natural tree, and permissions of higher levels (shorter path) can optionally be propagated down within this hierarchy.

Paths can be templated. When an API call requires permissions on a templated path, the path may contain references to parameters of the API call. These references are specified in curly braces. Some parameters are implicitly taken from the API call’s URI. For instance the permission path /nodes/{node} when calling /nodes/mynode/status requires permissions on /nodes/mynode, while the path {path} in a PUT request to /access/acl refers to the method’s path parameter.

Some examples are:

  • /nodes/{node}: Access to {pve} server machines

  • /vms: Covers all VMs

  • /vms/{vmid}: Access to specific VMs

  • /storage/{storeid}: Access to a storages

  • /pool/{poolname}: Access to VMs part of a pool

  • /access/groups: Group administration

  • /access/realms/{realmid}: Administrative access to realms

Inheritance

As mentioned earlier, object paths form a file system like tree, and permissions can be inherited down that tree (the propagate flag is set by default). We use the following inheritance rules:

  • Permissions for individual users always replace group permissions.

  • Permissions for groups apply when the user is member of that group.

  • Permissions replace the ones inherited from an upper level.

Pools

Pools can be used to group a set of virtual machines and data stores. You can then simply set permissions on pools (/pool/{poolid}), which are inherited to all pool members. This is a great way simplify access control.

What permission do I need?

The required API permissions are documented for each individual method, and can be found at http://pve.proxmox.com/pve-docs/api-viewer/

The permissions are specified as a list which can be interpreted as a tree of logic and access-check functions:

["and", <subtests>...] and ["or", <subtests>...]

Each(and) or any(or) further element in the current list has to be true.

["perm", <path>, [ <privileges>... ], <options>...]

The path is a templated parameter (see Objects and Paths). All (or, if the any option is used, any) of the listed privileges must be allowed on the specified path. If a require-param option is specified, then its specified parameter is required even if the API call’s schema otherwise lists it as being optional.

["userid-group", [ <privileges>... ], <options>...]

The caller must have any of the listed privileges on /access/groups. In addition there are two possible checks depending on whether the groups_param option is set:

  • groups_param is set: The API call has a non-optional groups parameter and the caller must have any of the listed privileges on all of the listed groups.

  • groups_param is not set: The user passed via the userid parameter must exist and be part of a group on which the caller has any of the listed privileges (via the /access/groups/<group> path).

["userid-param", "self"]

The value provided for the API call’s userid parameter must refer to the user performing the action. (Usually in conjunction with or, to allow users to perform an action on themselves even if they don’t have elevated privileges.)

["userid-param", "Realm.AllocateUser"]

The user needs Realm.AllocateUser access to /access/realm/<realm>, with <realm> referring to the realm of the user passed via the userid parameter. Note that the user does not need to exist in order to be associated with a realm, since user IDs are passed in the form of <username>@<realm>.

["perm-modify", <path>]

The path is a templated parameter (see Objects and Paths). The user needs either the Permissions.Modify privilege, or, depending on the path, the following privileges as a possible substitute:

  • /storage/...: additionally requires 'Datastore.Allocate`

  • /vms/...: additionally requires 'VM.Allocate`

  • /pool/...: additionally requires 'Pool.Allocate`

    If the path is empty, Permission.Modify on /access is required.

Command Line Tool

Most users will simply use the GUI to manage users. But there is also a fully featured command line tool called pveum (short for “Proxmox VE User Manager”). Please note that all Proxmox VE command line tools are wrappers around the API, so you can also access those functions through the REST API.

Here are some simple usage examples. To show help type:

 pveum

or (to show detailed help about a specific command)

 pveum help useradd

Create a new user:

 pveum useradd testuser@pve -comment "Just a test"

Set or Change the password (not all realms support that):

 pveum passwd testuser@pve

Disable a user:

 pveum usermod testuser@pve -enable 0

Create a new group:

 pveum groupadd testgroup

Create a new role:

 pveum roleadd PVE_Power-only -privs "VM.PowerMgmt VM.Console"

Real World Examples

Administrator Group

One of the most wanted features was the ability to define a group of users with full administrator rights (without using the root account).

Define the group:

 pveum groupadd admin -comment "System Administrators"

Then add the permission:

 pveum aclmod / -group admin -role Administrator

You can finally add users to the new admin group:

 pveum usermod testuser@pve -group admin

Auditors

You can give read only access to users by assigning the PVEAuditor role to users or groups.

Example1: Allow user joe@pve to see everything

 pveum aclmod / -user joe@pve -role PVEAuditor

Example1: Allow user joe@pve to see all virtual machines

 pveum aclmod /vms -user joe@pve -role PVEAuditor

Delegate User Management

If you want to delegate user management to user joe@pve you can do that with:

 pveum aclmod /access -user joe@pve -role PVEUserAdmin

User joe@pve can now add and remove users, change passwords and other user attributes. This is a very powerful role, and you most likely want to limit that to selected realms and groups. The following example allows joe@pve to modify users within realm pve if they are members of group customers:

 pveum aclmod /access/realm/pve -user joe@pve -role PVEUserAdmin
 pveum aclmod /access/groups/customers -user joe@pve -role PVEUserAdmin
Note
 The user is able to add other users, but only if they are members of group customers and within realm pve.

Pools

An enterprise is usually structured into several smaller departments, and it is common that you want to assign resources to them and delegate management tasks. A pool is simply a set of virtual machines and data stores. You can create pools on the GUI. After that you can add resources to the pool (VMs, Storage).

You can also assign permissions to the pool. Those permissions are inherited to all pool members.

Lets assume you have a software development department, so we first create a group

 pveum groupadd developers -comment "Our software developers"

Now we create a new user which is a member of that group

 pveum useradd developer1@pve -group developers -password
Note
 The -password parameter will prompt you for a password

I assume we already created a pool called “dev-pool” on the GUI. So we can now assign permission to that pool:

 pveum aclmod /pool/dev-pool/ -group developers -role PVEAdmin

Our software developers can now administrate the resources assigned to that pool.

1. AppId https://developers.yubico.com/U2F/App_ID.html
2. Multi-facet apps: https://developers.yubico.com/U2F/App_ID.html