[Samba] Samba crashes and won't restart

[Alexander Harm || ApfelQ]

Hi, we have Samba (4.15.7-Debian) running on Debian as our domain controller. In the last weeks we suffer from frequent failures of the samba-ad-dc.service which is also not restarted automatically by systemd. Manual restart works 100%.

The logs show the following entries:

[2022/06/19 12:55:34.464069, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
Auth: [LDAP,simple bind/TLS] user [CRAZE]\[cn=ka.h9.dc01,cn=users,dc=ds,dc=craze,dc=toys] at [Sun, 19 Jun 2022 12:55:34.423131 CEST] with [Plaintext] status [NT_STATUS_OK] workstation [KA-H9-DC01] rem[2022/06/19 12:18:33.218787, 1] ../../librpc/ndr/ndr.c:630(_ndr_pull_error)
[2022/06/19 12:36:31.346007, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
[2022/06/19 12:49:52.376820, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
[2022/06/19 12:49:56.569063, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
[2022/06/19 12:52:05.973201, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
[2022/06/19 12:54:21.548309, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
[2022/06/19 12:54:52.559657, 0] ../../source4/dsdb/dns/dns_update.c:85(dnsupdate_nameupdate_done)
dnsupdate_nameupdate_done: Failed DNS update with exit code 110
[2022/06/19 12:54:52.625303, 0] ../../source4/dsdb/dns/dns_update.c:108(dnsupdate_spnupdate_done)
../../source4/dsdb/dns/dns_update.c:108: Failed SPN update - with error code 110
[2022/06/19 12:55:34.464069, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
Auth: [LDAP,simple bind/TLS] user [CRAZE]\[cn=ka.h9.dc01,cn=users,dc=ds,dc=craze,dc=toys] at [Sun, 19 Jun 2022 12:55:34.423131 CEST] with [Plaintext] status [NT_STATUS_OK] workstation [KA-H9-DC01] remote host [ipv4:10.0.1.250:34546] became [CRAZE]\[ka.h9.dc01] [S-1-5-21-1451753080-565542361-3466525082-1204]. local host [ipv4:10.0.1.250:389]
[2022/06/19 12:55:41.861689, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
Auth: [LDAP,simple bind/TLS] user [CRAZE]\[cn=ka.h9.dc01,cn=users,dc=ds,dc=craze,dc=toys] at [Sun, 19 Jun 2022 12:55:41.838245 CEST] with [Plaintext] status [NT_STATUS_OK] workstation [KA-H9-DC01] remote host [ipv4:10.0.1.250:60036] became [CRAZE]\[ka.h9.dc01] [S-1-5-21-1451753080-565542361-3466525082-1204]. local host [ipv4:10.0.1.250:389]
[2022/06/19 12:55:50.963672, 3] ../../auth/auth_log.c:647(log_authentication_event_human_readable)
Auth: [LDAP,simple bind/TLS] user [CRAZE]\[cn=ka.h9.dc01,cn=users,dc=ds,dc=craze,dc=toys] at [Sun, 19 Jun 2022 12:55:50.926453 CEST] with [Plaintext] status [NT_STATUS_OK] workstation [KA-H9-DC01] remote host [ipv4:10.0.1.250:60038] became [CRAZE]\[ka.h9.dc01] [S-1-5-21-1451753080-565542361-3466525082-1204]. local host [ipv4:10.0.1.250:389]
[2022/06/19 12:56:20.945016, 0] ../../source4/dsdb/kcc/kcc_periodic.c:790(samba_kcc_done)
../../source4/dsdb/kcc/kcc_periodic.c:790: Failed samba_kcc - NT_STATUS_IO_TIMEOUT
[2022/06/19 12:56:49.827883, 0] ../../source4/samba/process_prefork.c:538(prefork_child_pipe_handler)
prefork_child_pipe_handler: Parent 995, Child 1010 terminated with signal 9
[2022/06/19 12:56:50.029270, 0] ../../source4/samba/process_prefork.c:481(prefork_restart)
prefork_restart: Restarting [rpc] pre-fork worker(0)
[2022/06/20 11:32:52.524375, 0] ../../source4/samba/server.c:626(binary_smbd_main)
samba version 4.15.7-Debian started.
Copyright Andrew Tridgell and the Samba Team 1992-2021

Does anyone have an idea why samba terminates and why it is not restarted?

Greetings, Alexander