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
Proxmox VE 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 Proxmox VE 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 (eg. 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 for small (or even medium) installations where users do not need access to anything outside of Proxmox VE. In this case users are fully managed by Proxmox VE and are able to change their own passwords via the GUI. - LDAP
-
It is possible to authenticate users via an LDAP server (eq. 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 beuid
.If Proxmox VE 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
(eg./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
Each realm can optionally be secured additionally by 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.
Proxmox VE 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 theoathtool
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.
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.
Proxmox VE 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 currently only be done from the command line, 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 -
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 Proxmox VE 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 theany
option is used, any) of the listed privileges must be allowed on the specified path. If arequire-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 callermust have any of the listed privileges on
/access/groups
. In addition there are two possible checks depending on whether thegroups_param
option is set:-
groups_param
is set: The API call has a non-optionalgroups
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 theuserid
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 withor
, 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>
refering to the realm of the user passed via theuserid
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 thePermissions.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 full 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
function 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 managenent 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
|
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
|
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.