This page describes the plan to fix Active Directory at UCC, potentially used in place of the previous AD from 2019 onwards.
Note that this document and the system it describes are in an early development stage.
> In a virtually perfect world, our servers will be named after what they do and not after species of fish.
For testing, a temporary virtual domain at UCC will be configured as ad.v.ucc.asn.au, and the domain name is VUCC, on a separate virtual network using only virtual machines (nested inside other virtual machines). The primary DNS server for domain is dc0.v.ucc.asn.au. The "primary" DC for domain will also be dc0.v.ucc.asn.au, and a second DC will be dc1.v.ucc.asn.au. Hopefully these can both be writable, although given the difficulty of making replication work reliably with Samba this may not be the case.
Setup Process
Domain Controllers
v.ucc.asn.au is delegated using separate zones in Mooneye's /etc/bind/named.conf.local.
zone "v.ucc.asn.au" { type forward; forward only; forwarders { 130.95.13.35; // vucc0 (proxmox VM on maltair, running dnsmasq) }; };
dnsmasq on the (virtualised) Proxmox VM host vucc0.ucc.asn.au then delegates the ad.v.ucc.asn.au domain to the domain controller(s). The domain controller dc0.v.ucc.asn.au is based off a clone of samurai, with clean samba configuration.
A fresh domain controller can probably be set up using the following instructions: (which is how dc0 was configured). Note: These instructions are valid for Samba 4.7 and 4.8.5, older versions of Samba may be missing important configuration options and newer ones may behave slightly differently.
- Configure the apt repositories and preferences
Edit /etc/apt/preferences.d/80-ucc-samba, add the following:
Package: * Pin: release a=stable Pin-Priority: 900 Package: * Pin: release a=stable-backports Pin-Priority: 800 Package: * Pin: release a=testing Pin-Priority: 99 Package: * Pin: release a=unstable Pin-Priority: 98
Edit /etc/apt/sources.list.d/debian-unstable.list:
# Testing repository - main, contrib and non-free branches deb http://mirror.waia.asn.au/debian testing main non-free contrib deb-src http://mirror.waia.asn.au/debian testing main non-free contrib # Testing security updates repository deb http://security.debian.org/ testing/updates main contrib non-free deb-src http://security.debian.org/ testing/updates main contrib non-free # Unstable repo main, contrib and non-free branches, no security updates here deb http://mirror.waia.asn.au/debian unstable main non-free contrib deb-src http://mirror.waia.asn.au/debian unstable main non-free contrib
Install packages:
apt-get update apt-get -t testing install samba sssd-ad sssd-tools sssd-krb5 libpam-sss libnss-sss libgpgme11 apt-get install net-tools vim less molly-guard chrony krb5-user libpam-krb5 rsync nfs-common finger sudo zsh git dnsutils mlocate
The rest of these instructions are based off the official Samba AD setup guide.
Disable the systemd units for the non-DC setup & default configuration:
systemctl stop smbd systemctl stop nmbd systemctl stop winbind systemctl disable smbd systemctl disable nmbd systemctl disable winbind
Remove all Samba database and config files, such as *.tdb and *.ldb files, so we can start with a clean installation.
rm -v /etc/samba/smb.conf /etc/krb5.conf /etc/krb5.keytab find /var/run/samba/ /var/lib/samba/ /var/cache/samba/ | grep -e tdb -e ldb | xargs rm -v
Provision the new domain:
samba-tool domain provision --use-rfc2307 --realm=ad.v.ucc.asn.au --domain=VUCC --server-role=dc --dns-backend=SAMBA_INTERNAL --adminpass=$PASSWORD
Copy /var/lib/samba/private/krb5.conf to /etc/krb5.conf:
cp /var/lib/samba/private/krb5.conf /etc/krb5.conf
Make sure /etc/krb5.conf looks something like this, add lines where necessary.
[libdefaults] default_realm = AD.V.UCC.ASN.AU dns_lookup_realm = false dns_lookup_kdc = true rdns = false forwardable = yes
Edit /etc/resolv.conf
search ad.v.ucc.asn.au search v.ucc.asn.au search ucc.asn.au nameserver 192.168.9.35
Edit /etc/nsswitch.conf
# /etc/nsswitch.conf # See http://wiki.ucc.asn.au/ActiveDirectoryNew passwd: files sss group: files sss shadow: files gshadow: files hosts: files dns networks: files protocols: db files services: db files sss ethers: db files rpc: db files netgroup: nis sss sudoers: files
and /etc/sssd/sssd.conf
[sssd] config_file_version = 2 domains = ad.v.ucc.asn.au services = nss, pam [domain/AD.V.UCC.ASN.AU] enumerate = true id_provider = ad auth_provider = ad chpass_provider = ad access_provider = ad ldap_id_mapping = false
enable sssd auth in pam via pam-auth-update
Start the samba service:
service samba-ad-dc enable service samba-ad-dc start service sssd enable service sssd start
DO NOT use winbind on a fomain controller, it sucks for multiple reasons.
Windows systems
Just join them to the domain. It Just Works (TM) - thanks Microsoft / Red Hat / IBM?!!
Linux systems
AD wasn't designed for Linux, and since most of our machines run Linux we have made things difficult for ourselves.
This is copied from ActiveDirectory and has not been tested yet, feel free to fix that.
Automatically using realmd
Thanks to realmd, joining machines to the domain is extremely simple.
Install packages: apt install realmd
Test to make sure you can connect to the domain: realm discover ad.ucc.gu.uwa.edu.au
Join to the domain using realm join -v -U <user> ad.ucc.gu.uwa.edu.au
- realmd defaults to using sssd, which is fine
- It installs any necessary packages.
- IT JUST WORKS!!
Except for one thing: comment the line use_fully_qualified_names = True in /etc/sssd/sssd.conf (prefix with a #)
- Then it works!
- Done.
Manual Method
Based on the instructions from https://wiki.samba.org/index.php/Setting_up_Samba_as_a_Domain_Member and https://wiki.samba.org/index.php/Authenticating_Domain_Users_Using_PAM Before configuring the domain ensure the following:
Install the required packages: apt install samba winbind krb5-user libpam-krb5 libpam-winbind libnss-winbind
Ensure the system is configured according to the SOE.
edit /etc/krb5.conf to point to the new domain:
[libdefaults] default_realm = ad.ucc.gu.uwa.edu.au dns_lookup_realm = false dns_lookup_kdc = trueMake the following /etc/samba/smb.conf:
[global] # Configure the domain infomation security = ads realm = ad.ucc.gu.uwa.edu.au workgroup = UCCDOMAYNE # use winbind to map users and groups winbind enum users = yes winbind enum groups = yes winbind use default domain = yes kerberos method = secrets and keytab #Config gid/sid mapping based on AD attributes winbind nss info = rfc2307 idmap config * : backend = tdb idmap config * : range = 13000-17999 #idmap config for UCCDOMAYNE idmap config UCCDOMAYNE:backend = ad idmap config UCCDOMAYNE:schema_mode = rfc2307 idmap config UCCDOMAYNE:range = 1-999999 idmap config UCCDOMAYNE:unix_nss_info = yes idmap config UCCDOMAYNE:unix_primary_group = yesJoin the machine to the domain with: net ads join -U <username>.
configure pam using pam-auth-update and enable Winbind NT/AD authentication.
configure nsswitch.conf
# /etc/nsswitch.conf # # Example configuration of GNU Name Service Switch functionality. # If you have the `glibc-doc-reference' and `info' packages installed, try: # `info libc "Name Service Switch"' for information about this file. passwd: compat winbind group: compat winbind shadow: files gshadow: files hosts: files mdns4_minimal [NOTFOUND=return] dns networks: files protocols: db files services: db files ethers: db files rpc: db files netgroup: nis
- start the services:
winbindd nmbd smbd
- Make sure the computer can fetch the domain users and groups with:
wbinfo -g` and `wbinfo -u`
Diagnostics
Sometimes group memberships don't seem to be updated, this can often be fixed by clearing the cache:
sss_cache -E if using sssd
net cache flush if using winbind
- Or if the above fails to have an effect, try rejoining to the domain using the instructions below.
