Join Raspberry Pi to Active Directory (Rasbpian) Using Realmd
I’ve been working with Ansible lately so I’ve been trying to automate everything I can. I work with Linux systems in AD, so I’ve been trying to figure out a way to auto deploy and join to my domain. Since I had a few Pis laying around, I decided to set them up on my domain as well. I will also include a link to my Ansible playbook that automates this process. This guide assumes you have updated your apt repositories recently.
Big thanks to Wolfhaven’s excellent post on this topic.
Be sure to check out my Raspberry Pi Headless setup (coming soon) using PiBakery to auto-connect to your wireless to automate this process even more.
I’m running this on Raspbian Jessie Lite 4.4.
In order for Kerberos to resolve correctly, you will need to add your fully qualified domain name to your hosts file. At this point you’ll probably want to rename your pi to whatever hostname you are going to stick with. You’ll need to edit
127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback ff02::1 ip6-allnodes ff02::2 ip6-allrouters 127.0.1.1 raspiname.domain.local raspiname
I usually reboot the pi after changing the hostname file.
For Kerberos, the Pi needs to point to the same NTP server as the Domain Controller. In my case, I use my PDC as my NTP server. Make sure you have the
ntp package installed.
sudo apt install -y ntp
Once NTP is installed, edit the ntp.conf file and point it to your NTP server.
My example ntp.conf:
driftfile /var/lib/ntp/drift restrict 127.0.0.1 restrict -6 ::1 server NTPSERVER
Make sure you restart the ntp service to reflect your changes.
sudo systemctl restart ntp
ntpq -p to verify ntp is pointing to the correct server.
ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== *your.ntp.server 126.96.36.199 3 u 330 1024 377 0.826 -9.921 14.298
You can also use
ntpstat to get simplified results:
ntpstat synchronised to NTP server (your.ip.address) at stratum 4 time correct to within 196 ms polling server every 1024 s
Install Required Packages
sudo apt install -y ntp python-pip realmd sssd adcli krb5-user sssd-tools samba-common packagekit samba-common-bin samba-libs
Kerberos may pop up with a config and ask you for the Kerberos 5 default realm. This is your base AD Domain in all caps.
YOURDOMAIN.LOCAL. To verify this is set correctly, check your
/etc/krb5.conf file. Here’s my example file:
[libdefaults] default_realm = YOURDOMAIN.LOCAL [login] krb4_convert = true krb4_get_tickets = false
krb5.conf file will probably have a lot of MIT Kerberos configuration items, but the key line to make sure exists is the
[libdefaults] default_realm = YOURDOMAIN.LOCAL
Again, make sure it’s in all CAPS.
Avahi Configuration change
This is an important step if you are using a domain with a .local FQDN.
Thanks to the information from this post, I was able to figure out why I wasn’t able to resolve my .local devices using DNS. By default, avahi fails if mDNS is enabled and the host is not found in mDNS. You can fix this so that if something isn’t found in mDNS, it will fail over to your local DNS server. We have to edit two files to fix this with the version of Raspbian Jessie that I’m using.
/etc/nsswitch.conf and remove the text
[NOTFOUND=return]. Your text should look like:
hosts: files mdns4_minimal dns #hosts: files mdns4_minimal [NOTFOUND=return] dns
I copied the original line and just commented it out. Save that config and then edit
/etc/avahi/avahi-daemon.conf. Find the line containing
#domain-name=.local, uncomment it, and change it to
domain-name=.alocal. In my config, the text is located at line 23. Your config should now contain:
... [server] #host-name=foo domain-name=.alocal ...
Save the file and run
sudo systemctl restart avahi-daemon.service
You can test and make sure this worked by pinging a device on your network using the FQDN with
Make sure your
/etc/sssd/sssd.conf file contains something simliar to:
[sssd] domains = yourdomain.local config_file_version = 2 services = nss, pam [domain/yourdomain.local] ad_domain = yourdomain.local krb5_realm = YOURDOMAIN.LOCAL realmd_tags = manages-system joined-with-adcli cache_credentials = True id_provider = ad krb5_store_password_if_offline = True default_shell = /bin/bash ldap_id_mapping = True use_fully_qualified_names = False fallback_homedir = /home/%u access_provider = ad auth_provider = ad chpass_provider = ad access_provider = ad ldap_schema = ad dyndns_update = true dyndns_refresh_interval = 43200 dyndns_update_ptr = true dyndns_ttl = 3600
PAM config /etc/pam.d/common-session
Make sure your
/etc/pam.d/common-session has the following line in it:
session required pam_mkhomedir.so skel=/etc/skel/ umask=0022
This should ensure home directories work correctly.
Make the following changes to your
/etc/realmd.conf file. You can leave out the OS info if you want, but this is what is shown in your active directory computer object. When I’m using Ansible, I have Ansible auto-fill in this information to dynamically match the OS info.
[active-directory] os-name = Raspbian os-version = 4.4 [service] automatic-install = yes [users] default-home = /home/%u default-shell = /bin/bash [yourdomain.local] user-principal = yes fully-qualified-names = no
fully-qualified-names allows you to log on with your active directory account as
user instead of
[users] section configures the home directory for new accounts as they log in, and configures the default shell.
realmd.conf file created, you should now be able to discover the realm. Run the command:
Depending on how you’ve set up your IP address (DHCP or static) and whether or not your NIC is set to auto-discover your domain, you may get results about your domain or it may return with:
See: journalctl REALMD_OPERATION=r128938.5757 realm: No default realm discovered
If nothing shows up by default, try the command:
realm discover yourdomain.local
That should get you some results. Mine gives me:
mydomain.local type: kerberos realm-name: MYDOMAIN.LOCAL domain-name: mydomain.local configured: no
Once you are discovering properly, you can move on to the next step.
To get a Kerberos ticket, run the command:
kinit -V AD-Username
If everything is configured correctly, you should receive a ticket.
Using default cache: /tmp/krb5cc_1000 Using principal: user@YOURDOMAIN.LOCAL Password for user@YOURDOMAIN.LOCAL: Authenticated to Kerberos v5
Now you can join the domain by running:
sudo realm join -U username yourdomain.local
If everything worked, you should now see the AD Computer Object in your ADUC panel.
You can verify this is working by using the following command on an Active Directory username:
That should return the uid and a list of groups that username is a part of. You can now log into your pi using your active directory credentials!
Add Domain Admins to Sudoers
You can add your Domain Admins group to allow sudo automatically. You can configure this to work with any group, not just Domain Admins. Make sure the following line exists when running
%domain\ admins ALL=(ALL:ALL) ALL
Add that somewhere in your sudoers file. If you are a member of Domain Admins, whenever you log in you are automatically granted sudo rights.
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