thank's for your answer .
see below .
----- Messaggio originale -----
Da: "Rowland Penny via samba" <samba at lists.samba.org>
A: "samba" <samba at lists.samba.org>
Cc: "Rowland Penny" <rpenny at samba.org>
Inviato: Gioved?, 9 ottobre 2025 10:44:17
Oggetto: Re: [Samba] Failed to find a writeable DC
On Wed, 8 Oct 2025 22:44:19 +0200 (CEST)
Fabrizio Rompani via samba <samba at lists.samba.org> wrote:
> hi all
> I have a DC used to manage user authentication to nextcloud app
> installed on the same server. I moved NC to a new server leaving
> samba-ad-dc on the old one ( appropriate firewall rules exits ) Now I
> want to move samba to new VM so I can shutdown the old one.
>
> To do so ,I'm trying to join a second DC installed to the new machine
> and then , after move all roles , I can demote and switch off the old
> VM.
>
> BUT : when I try to join the second DC
> I got this :
> root at grants-dc:~# samba-tool domain join s4ad.domain.org DC -U
> administrator --realm=S4AD.DOMAIN.ORG -W S4AD INFO 2025-10-08
Either that is bad sanitisation or that is your problem there,
's4ad.domain.org' != S4AD.DOMAIN.ORG' (and I am discounting the
case)
yes , my fault : bad sanitisation!
You also do not need the '-W' switch
ok
> 22:29:30,946 pid:3292 /usr/lib/python3/dist-packages/samba/join.py
> #106: Finding a writeable DC for domain 's4ad.domain.org' ERROR:
> Failed to find a writeable DC for domain 's4ad.domain.org': The
> object was not found.
>
>
> Here my config files:
>
>
>
> * Actual (unique) DC : Ubuntu 20.04 , samba 4.15.13
>
> hosts:
> xx.xx.xx.xx grants.s4ad.domain.org
>
> krb5.conf:
> [libdefaults]
> default_realm = S4AD.DOMAIN.ORG
> dns_lookup_kdc = true
> dns_lookup_realm = false
>
> smb.conf
> [global]
> dns forwarder = 127.0.0.1
That dns forwarder isn't going to work, you are forwarding the DC to
itself.
OK . changed in 9.9.9.9
ALso : I use bind9
> netbios name = GRANTS
> realm = S4AD.DOMAIN.ORG
> server role = active directory domain controller
> workgroup = S4AD
> server services = -dns
> interfaces = eth0 lo
> bind interfaces only = yes
>
>
>
> * New DC Ubuntu 24.04 samba 4.23
>
> hosts:
> yy.yy.yy.yy grants-dc.s4ad.domain.org
>
> /etc/netplan/
>
> network:
> version: 2
> ethernets:
> ens18:
> addresses:
> - "yy.yy.yy.yy/24"
> nameservers:
> addresses:
> - xx.xx.xx.xx
> search: []
>
>
>
>
>
>
> * dig grants.s4ad.domain.org
>
> grants.s4ad.domain.org. 0 IN A xx.xx.xx.xx
>
>
>
>
>
> * root at grants-dc:~# host -t SRV
> _ldap._tcp.dc._msdcs.s4ad.domain.org
>
> _ldap._tcp.dc._msdcs.s4ad.domain.org has SRV record 0 100 389
> grants.s4ad.domain.org.
>
>
>
>
> * root at grants-dc:~# ping grants.s4ad.domain.org
>
> PING grants.s4ad.domain.org (89.116.29.118) 56(84) bytes of data.
> 64 bytes from grants.s4ad.domain.org (xx.xx.xx.xx): icmp_seq=1 ttl=53
> time=280 ms 64 bytes from grants.s4ad.domain.org (xx.xx.xx.xx):
> icmp_seq=2 ttl=53 time=290 ms ^C
What is in the /etc/resolv.conf on the new DC ?
search s4ad.domain.org
nameserver xx.xx.xx.xx ( old DC server IP )
also :
dig grants.s4ad.domain.org
grants.s4ad.domain.org. 900 IN A xx.xx.xx.xx
host -t SRV _ldap._tcp.s4ad.domain.org
_ldap._tcp.s4ad.domain.org has SRV record 0 100 389 grants.s4ad.domain.org.
I still have same error:
ERROR: Failed to find a writeable DC for domain 's4ad.domain.org': The
object was not found
What about a different approach :
backup the online DC ( samba 4.15 ) and restore into new samba 4.23 .
change resolv.conf and Nextcloud ldap to point itself : grants-dc
what do you think about ?
thanks
rf
Rowland
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