[Samba] Failed to obtain server credentials, perhaps a standalone server?

["Stefan Günther"]

Hello,

we are running Samba 4.1.6 on Ubuntu 14.04 LTS 64 bit.

Out of a sudden we weren't able to access the server. After we restarted the server, we found a running samba process, but no dns and kerberos.

Starting Samba with "samba -i -M single" returned the following output:

dreplsrv_partition[DC=DomainDnsZones,DC=companynet,DC=net] loaded
dreplsrv_partition[DC=ForestDnsZones,DC=companynet,DC=net] loaded
ldb_wrap open of secrets.ldb
ldb_wrap open of idmap.ldb
kccsrv_partition[DC=companynet,DC=net] loaded
kccsrv_partition[CN=Configuration,DC=companynet,DC=net] loaded
kccsrv_partition[CN=Schema,CN=Configuration,DC=companynet,DC=net] loaded
kccsrv_partition[DC=DomainDnsZones,DC=companynet,DC=net] loaded
kccsrv_partition[DC=ForestDnsZones,DC=companynet,DC=net] loaded
Calling DNS name update script
Calling SPN name update script
task_server_terminate: [Failed to obtain server credentials, perhaps a standalone server?: NT_STATUS_NOT_FOUND
]
/usr/sbin/smbd: smbd version 4.1.6-Ubuntu started.
/usr/sbin/smbd: Copyright Andrew Tridgell and the Samba Team 1992-2013
/usr/sbin/smbd: Registered MSG_REQ_POOL_USAGE
/usr/sbin/smbd: Registered MSG_REQ_DMALLOC_MARK and LOG_CHANGED
/usr/sbin/smbd: lp_load_ex: refreshing parameters
/usr/sbin/smbd: Initialising global parameters
/usr/sbin/smbd: rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
/usr/sbin/smbd: params.c:pm_process() - Processing configuration file "/etc/samba/smb.conf"
/usr/sbin/smbd: Processing section "[global]"
/usr/sbin/smbd: Processing section "[netlogon]"
/usr/sbin/smbd: Processing section "[sysvol]"
/usr/sbin/smbd: Processing section "[profiles]"
/usr/sbin/smbd: Processing section "[users]"
/usr/sbin/smbd: Processing section "[kuris]"
/usr/sbin/smbd: Processing section "[pdm]"
/usr/sbin/smbd: Processing section "[scanfront]"
/usr/sbin/smbd: Processing section "[formatsoftware]"
/usr/sbin/smbd: Processing section "[edv]"
/usr/sbin/smbd: Processing section "[dokumente]"
/usr/sbin/smbd: Processing section "[printers]"
/usr/sbin/smbd: Processing section "[Test]"
/usr/sbin/smbd: adding IPC service
/usr/sbin/smbd: added interface em2 ip=192.168.194.7 bcast=192.168.194.255 netmask=255.255.255.0
/usr/sbin/smbd: added interface em1 ip=10.20.30.40 bcast=10.20.30.255 netmask=255.255.255.0
/usr/sbin/smbd: loaded services
/usr/sbin/smbd: Becoming a daemon.
/usr/sbin/smbd: ldb_wrap open of idmap.ldb
samba_terminate: Failed to obtain server credentials, perhaps a standalone server?: NT_STATUS_NOT_FOUND


Nevertheless, samba has started, but doesn't offer any services:


15561 ?        S      0:00 samba -D
15563 ?        Ss     0:00 /usr/sbin/smbd -D --option=server role check:inhibit=yes --foreground
15578 ?        S      0:00 /usr/sbin/smbd -D --option=server role check:inhibit=yes --foreground

The file idmap.ldb is readable via ldbedit and the files secrets.ldb and secrets.keytab (which I assume have something to do with credentials) are also there and readable.

Where does Samba look for credentials and what could be the reason that it does not finde them?

[global]
        workgroup = COMPANYNET
        realm = COMPANYNET.NET
        netbios name = DBSRV
        server role = active directory domain controller
        dns forwarder = 192.168.194.6
        idmap_ldb:use rfc2307 = yes
        server services = +dns +s3fs +rpc +nbt +wrepl +ldap +cldap +kdc +drepl +winbind +ntp_signd +kcc
        acl:search = no
        remote announce = 192.168.194.255/COMPANYNET
        syslog = no
        socket options=SO_RCVBUF=131072 SO_SNDBUF=131072 TCP_NODELAY
        min receivefile size = 16384
        use sendfile = true
        aio read size = 16384
        aio write size = 16384
        map to guest = never
        log file = /var/log/samba/%U.log
        log level = 3

Thanks for any hints or suggestions,

Stefan