Realmd

Realmd discovers information about the domain or realm automatically and does not require complicated configuration in order to join a domain or realm, like IdM, Microsoft Active Directory, or Kerberos realms.

Using realmd is easy. A one-line command and it configures Linux systems service like sssd to do the network authentication and user account lookups.

(https://www.freedesktop.org/software/realmd/)

USAGE:

Note: realmd is supported starting leap 15.2

install:

cat /etc/os-release 
NAME="openSUSE Leap"
VERSION="15.2"

zypper in  realmd

Joining a Microsoft Active directory domain

zypper in realmd adcli sssd sssd-tools sssd-ad samba-client

edit the network configuration to the add

  vi /etc/sysconfig/network/config
  # change DNS settings to refer to AD
  NETCONFIG_DNS_STATIC_SERVERS="YOUR_SERVER_IP"

update network with

   netconfig update

join the linux machine to Active Directory domain

 realm join MYDOMAIN.COM 
 Password for Administrator:     # AD's Administrator password
 
 vi /etc/pam.d/common-session
 # add to the end if you need (auto create a home directory at initial login)
 session optional        pam_mkhomedir.so skel=/etc/skel umask=077

Testing your setup

You should able now to login with users from Active Directory Domain.

  Assuming you are root, this should work:
  su - myADuser
  id 
  uid=555401133(myADuser) gid=555401130(userad) groups=555401130(userad)

Automatic Mapping

Note that realmd configures sssd by default with automatic mapping, this means all users/groups IDs are automatically generated; if you need 1:1 correspondence, you can still disable this option adding the flag to cli:

 realm join --computer-ou="ou=Linux Computers,dc=domain,dc=com" --automatic-id-mapping=no

or you can edit sssd.conf file

You will also need to setup Microsoft Active Directory to support POSIX attributes if you disable automatic mapping.

References:

Source code:

https://gitlab.freedesktop.org/realmd/realmd

Realmd doc: https://www.freedesktop.org/software/realmd/

SSSD upsteam doc: https://sssd.io/