Active Directory

This document describes the process of integrating Workbench with AD using realmd and sssd. For alternative methods of configuration, refer to the Red Hat and Ubuntu documentation.

Caution

Workbench can be configured to use Active Directory (AD) as the user authentication service, which allows users to authenticate to Workbench via their AD credentials. This document describes the process of integrating Workbench with AD using realmd and sssd. For alternative methods of configuration, refer to the Red Hat and Ubuntu documentation. This section is a suggested set of steps that may not be appropriate for your configuration. Therefore, you may have to make changes to the steps below for your specific configuration. This content is not meant to be a step-by-step guide that works across all configurations.

This setup requires the machine with Workbench to be joined to a Windows domain and it requires configuring PAM to use AD as its identity provider. This configuration allows AD accounts to be used along with local system accounts. Workbench requires the use of local system accounts regardless of the authentication method that is used.

This setup can be configured in many different ways and is typically governed by the systems and services that your organization already has in place.

For more information on how Workbench works with PAM sessions, refer to the PAM Sessions section.

Prerequisites

This article assumes that you have an Active Directory server. In this example, the Windows server is configured with a hostname of winserver.demo.rstudioservices.com:

Active Directory configurations outside of Posit products is not supported

Posit does not provide support for Active Directory configurations outside of Posit products.

The hostname of the AD server should be resolvable by all of the servers that you want to join to the Windows domain. For this example, the Linux machine where Workbench is installed should be able to resolve the AD hostname:

Terminal

$ nslookup winserver.demo.rstudioservices.com 
Server: 127.0.0.53 
Address: 127.0.0.53#53

Non-authoritative answer: 
Name: winserver.demo.rstudioservices.com 
Address: 172.31.31.231

You should also have Workbench installed with the default configuration that uses local system accounts.

Join AD domain

The steps outlined below are examples of how to join an Active Directory domain in RHEL/CentOS and Ubuntu operating systems. Additionally, the steps should be similar for other versions of RHEL/CentOS and Ubuntu but may not be identical.

Posit Workbench supports more operating systems than shown in the examples below. For a full list, visit the Posit Platform Support page.

Install the LDAP client system dependencies for your Linux distribution:

$ sudo yum install realmd oddjob oddjob-mkhomedir sssd adcli samba-common \
    samba-common-tools krb5-workstation openldap-clients policycoreutils-python

$ sudo yum install samba-common-tools realmd oddjob oddjob-mkhomedir \
    sssd adcli krb5-workstation

$ sudo dnf install samba-common-tools realmd oddjob oddjob-mkhomedir \
    sssd adcli krb5-workstation

$ sudo apt install realmd sssd sssd-tools libnss-sss libpam-sss adcli \
    samba-common-bin oddjob oddjob-mkhomedir packagekit

Use the following realm join command to join the AD domain. In this example, we are using the Administrator user on AD (you will be prompted for the password):

Terminal

$ sudo realm join -v -U Administrator winserver.demo.rstudioservices.com

[... truncated output ...]
Successfully enrolled machine in realm

Confirm the connection by running the realm list command:

Terminal

$ realm list

demo.rstudioservices.com 
  type: kerberos 
  realm-name: DEMO.RSTUDIOSERVICES.COM 
  domain-name: demo.rstudioservices.com 
  configured: kerberos-member 
  server-software: active-directory 
  client-software: sssd 
  required-package: sssd-tools 
  required-package: sssd 
  required-package: libnss-sss 
  required-package: libpam-sss 
  required-package: adcli 
  required-package: samba-common-bin 
  login-formats: %U@demo.rstudioservices.com 
  login-policy: allow-realm-logins

You can use the id and getent commands to verify that the users on the AD domain can be used on the machine with Workbench, for example:

Terminal

$ id administrator@demo.rstudioservices.com 
uid=1684800500(administrator@demo.rstudioservices.com) 
gid=1684800513(domain users@demo.rstudioservices.com) 
groups=1684800513(domain users@demo.rstudioservices.com), 
1684800520(group policy creator owners@demo.rstudioservices.com), 
1684800518(schema admins@demo.rstudioservices.com), 
1684800512(domain admins@demo.rstudioservices.com), 
1684800572(denied rodc password replication group@demo.rstudioservices.com),
1684800519(enterprise admins@demo.rstudioservices.com)

$ getent passwd administrator@demo.rstudioservices.com 
administrator@demo.rstudioservices.com:*:1684800500:1684800513: 
Administrator:/home/administrator@demo.rstudioservices.com:/bin/bash

Information on joining an AD domain with realmd

The process of joining the AD domain with realmd resulted in the following changes to the system:

Joined the domain by creating an account entry for the system in the directory.
Created the /etc/krb5.keytab host keytab file.
Configured the domain in SSSD and restarted the service.
Enabled domain users for the system services in PAM configuration and the /etc/nsswitch.conf file.

If you want to configure these items manually, then refer to the documentation described in the PAM Sessions section.

UID and GID

The default configuration created by realm uses LDAP ID mapping. For more details on using POSIX attributes such as UIDs and GIDs, refer to the sssd.conf(5) man page or external SSSD documentation.

Configure home directory creation

By default, users from the AD domain will not have a home directory on the Linux server. Because sessions in Workbench require that the user’s home directories are present, we will configure PAM sessions to automatically create the home directories.

In the PAM session configuration file located at /etc/pam.d/common-session, locate the line that contains session required pam_unix.so, and add the following line immediately below it:
```
/etc/pam.d/common-session
```
```
session required pam_unix.so
session required pam_mkhomedir.so skel=/etc/skel/ umask=0022
```
You can test the automatic creation of home directories by switching to an AD user using the su or ssh commands:
```
Terminal
```
```
$ su administrator@demo.rstudioservices.com 
Password: 
Creating directory '/home/administrator@demo.rstudioservices.com'.

$ ssh -l testuser@demo.rstudioservices.com linux-client
```
Customizing the location of home directories for AD users
By default, home directories will be created in /home.

To customize the directory location or template, edit the /etc/sssd/sssd.conf file by adding the override_homedir option in the target domain. This is useful when configuring user data in Workbench in a different location (e.g., when working with an NFS server).

For example, the following configuration can be used in /etc/sssd/sssd.conf to specify a home directory location of /usr/home/{ domain_name }/{ user_name }:
/etc/sssd/sssd.conf

[domain/demo.rstudioservices.com] [... file truncated ...] override_homedir = /usr/home/%d/%u
For additional details on SSSD configuration options, refer to the sssd.conf(5) man page.

Configure PAM profile

Now that the system with Workbench is configured for authentication via AD users, you can copy the login PAM profile for use with Workbench:
```
Terminal
```
```
$ cp /etc/pam.d/login /etc/pam.d/rstudio
```

You can test your updated PAM configuration outside of Workbench using the provided pamtester utility:

Terminal

$ sudo /usr/lib/rstudio-server/bin/pamtester --verbose   
rstudio testuser@demo.rstudioservices.com    
authenticate acct_mgmt setcred open_session close_session   
pamtester: invoking pam_start(rstudio, testuser@demo.rstudioservices.com, ...)   
pamtester: performing operation - authenticate   
Password:   
[... truncated output ...]   
pamtester: successfully opened a session   
pamtester: performing operation - close_session   
pamtester: session has successfully been closed

If a pam_acct_mgmt error is observed with the following output

pamtester: successfully authenticated       
pamtester: performing operation - acct_mgmt       
pamtester: Permission denied

Edit the /etc/pam.d/common-account configuration file to remove account checking from the pam_sss module by commenting out the following line:

[... truncated file ...]  
# account        [default=bad success=ok user_unknown=ignore]    pam_sss.so

For more information on the pamtester utility, refer to Testing and Troubleshooting.

Log in to Workbench

You should now be able to log into Workbench using Active Directory users.

To log in, use the format username@domain for the username and the corresponding password.

Generating Kerberos tickets

If you installed all of the required dependencies, and a Kerberos Key Distribution Center (KDC) is available on the Windows domain, then you should have access to generate Kerberos tickets from within sessions in Workbench by using the kinit command.

In a terminal, for example, run:

"Terminal

$ kinit testuser@DEMO.RSTUDIOSERVICES.COM

You can also run this command from within the Terminal pane in Workbench: