AD integration - ssh/sudoers using AD accounts

Use NTP for time synchronization

apt install chrony 
# Use AD DCs as NTP source in /etc/chrony/chrony.conf 
server dc01.domain.local iburst 
server dc02.domain.local iburst 

systemctl enable chrony ; systemctl restart chrony 
timedatectl set-timezone Pacific/Auckland 
timedatectl ; chronyc makestep 
systemctl disable systemd-timesyncd ; systemctl stop system-timesyncd 

Allow sudo from required AD group, add to /etc/sudoers.d/ad-admins

%Domain\ Admins ALL=(ALL) ALL 

Enable AD authentication and DNS registration

yum -y install sssd  adcli realmd samba-common-tools oddjob oddjob-mkhomedir 
apt install sssd-ad  sssd-tools realmd adcli 
realm -v discover domain.local
realm join domain.local --user administrator  

Add those to /etc/sssd/sssd.conf

access_provider = simple 
simple_allow_groups = Domain Admins@domain.local 
use_fully_qualified_names = false 
dyndns_update = true 
dyndns_refresh_interval = 43200 
dyndns_update_ptr = true 
dyndns_ttl = 3600 

Now restart it

systemctl restart sssd.service 

Enable homedir creation

pam-auth-update

Restrict root login from ssh in /etc/ssh/sshd.conf

PermitRootLogin no