User Management in Proxmox

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. Users are allowed to change passwords.

Terms and Definitions

Users

A Proxmox VE user name consists of 2 parts: <userid>@<realm>. The login screen on the GUI shows them a separate items, but it is internally used as single string.

We store the following attribute for users (/etc/pve/user.cfg):

• first name
• last name
• email address
• expiration date
• flag to enable/disable account
• comment
• Superuser

The traditional unix superuser account is called ‘root@pam’. All system mails are forwarded to the email assigned to that account.

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.

Objects and Paths
Access permissions are assigned to objects, such as a virtual machines (/vms/{vmid}) or a storage (/storage/{storeid}) or a pool of resources (/pool/{poolname}). We use filesystem like paths to address those objects. Those paths form a natural tree, and permissions can be inherited down that hierarchy.

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 uses to set permissions.

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 system
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
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 using the CLI:

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

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

Permissions
Permissions are the way we control access to objects. In technical terms they are simply a triple containing <path,user,role>. This concept is also known as access control lists. Each permission specifies a subject (user or group) and a role (set of privileges) on a specific path.

When a subject requests an action on an object, the framework looks up the roles assigned to that subject (using the object path). The set of roles defines the granted privileges.

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

permission for individual users always overwrite group permission.
permission for groups apply when the user is member of that group.
permission set at higher level always overwrites inherited permissions.
What permission do I need?
The required API permissions are documented for each individual method, and can be found here: http://pve.proxmox.com/pve2-api-doc/

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.

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’). I will use that tool in the following examples. 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 (Forum bug):

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 administartor 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

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.

Resource Limits
Future versions will allow you to specify resource limits for pools (currently not implemented).

Src: https://pve.proxmox.com/wiki/User_Management#Permissions