Join a Red Hat Enterprise Linux 7 virtual machine to a managed domain

This article shows you how to join a Red Hat Enterprise Linux (RHEL) 7 virtual machine to an Azure AD Domain Services managed domain.

Before you begin

To perform the tasks listed in this article, you need:

  1. A valid Azure subscription.
  2. An Azure AD directory - either synchronized with an on-premises directory or a cloud-only directory.
  3. Azure AD Domain Services must be enabled for the Azure AD directory. If you haven't done so, follow all the tasks outlined in the Getting Started guide.
  4. Ensure that you have configured the IP addresses of the managed domain as the DNS servers for the virtual network. For more information, see how to update DNS settings for the Azure virtual network
  5. Complete the steps required to synchronize passwords to your Azure AD Domain Services managed domain.

Provision a Red Hat Enterprise Linux virtual machine

Provision a RHEL 7 virtual machine in Azure, using any of the following methods:

Important

  • Deploy the virtual machine into the same virtual network in which you have enabled Azure AD Domain Services.
  • Pick a different subnet than the one in which you have enabled Azure AD Domain Services.

Connect remotely to the newly provisioned Linux virtual machine

The RHEL 7.2 virtual machine has been provisioned in Azure. The next task is to connect remotely to the virtual machine using the local administrator account created while provisioning the VM.

Follow the instructions in the article How to log on to a virtual machine running Linux.

Configure the hosts file on the Linux virtual machine

In your SSH terminal, edit the /etc/hosts file and update your machine’s IP address and hostname.

sudo vi /etc/hosts

In the hosts file, enter the following value:

127.0.0.1 contoso-rhel.contoso100.com contoso-rhel

Here, 'contoso100.com' is the DNS domain name of your managed domain. 'contoso-rhel' is the hostname of the RHEL virtual machine you are joining to the managed domain.

Install required packages on the Linux virtual machine

Next, install packages required for domain join on the virtual machine. In your SSH terminal, type the following command to install the required packages:

```
sudo yum install realmd sssd krb5-workstation krb5-libs
```

Join the Linux virtual machine to the managed domain

Now that the required packages are installed on the Linux virtual machine, the next task is to join the virtual machine to the managed domain.

  1. Discover the AAD Domain Services managed domain. In your SSH terminal, type the following command:

    sudo realm discover CONTOSO100.COM
    

    Note

    Troubleshooting: If realm discover is unable to find your managed domain:

    • Ensure that the domain is reachable from the virtual machine (try ping).
    • Check that the virtual machine has indeed been deployed to the same virtual network in which the managed domain is available.
    • Check to see if you have updated the DNS server settings for the virtual network to point to the domain controllers of the managed domain.
  2. Initialize Kerberos. In your SSH terminal, type the following command:

    Tip

    • Ensure that you specify a user who belongs to the 'AAD DC Administrators' group.
    • Specify the domain name in capital letters, else kinit fails.
    kinit bob@CONTOSO100.COM
    
  3. Join the machine to the domain. In your SSH terminal, type the following command:

    Tip

    Use the same user account you specified in the preceding step ('kinit').

    sudo realm join --verbose CONTOSO100.COM -U 'bob@CONTOSO100.COM'
    

You should get a message ("Successfully enrolled machine in realm") when the machine is successfully joined to the managed domain.

Verify domain join

Verify whether the machine has been successfully joined to the managed domain. Connect to the domain joined RHEL VM using a different SSH connection. Use a domain user account and then check to see if the user account is resolved correctly.

  1. In your SSH terminal, type the following command to connect to the domain joined RHEL virtual machine using SSH. Use a domain account that belongs to the managed domain (for example, 'bob@CONTOSO100.COM' in this case.)

    ssh -l bob@CONTOSO100.COM contoso-rhel.contoso100.com
    
  2. In your SSH terminal, type the following command to see if the home directory was initialized correctly.

    pwd
    
  3. In your SSH terminal, type the following command to see if the group memberships are being resolved correctly.

    id
    

Troubleshooting domain join

Refer to the Troubleshooting domain join article.