1、修改配置文件sssd.conf
vim /etc/sssd/sssd.conf

[domain/LDAP]
cache_credentials = true
debug_level = 9

[sssd]
debug_level = 9

[nss]
debug_level = 9

[pam]
debug_level = 9

[ssh]
debug_level = 9

日志级别说明图

2、重启SSSD服务
Redhat: service sssd restart
SUSE: rcsssd restart

3、在/var/log/sssd/查看日志
如何查看sssd的日志在哪个文件中，可以通过如下方法：

# rpm -ql sssd | grep log
/var/log/sssd
# ll /var/log/sssd/
总用量 0
-rw------- 1 root root 0 3月  25 15:51 ldap_child.log
-rw------- 1 root root 0 3月  25 15:51 sssd_LDAP.log
-rw------- 1 root root 0 3月  25 15:51 sssd.log
-rw------- 1 root root 0 3月  25 15:51 sssd_nss.log
-rw------- 1 root root 0 3月  25 15:51 sssd_pam.log

附官方说明：
Checking SSSD Log Files
SSSD uses a number of log files to report information about its operation, located in the /var/log/sssd/directory. SSSD produces a log file for each domain, as well as an sssd_pam.log and an sssd_nss.log file.
Additionally, the /var/log/secure file logs authentication failures and the reason for the failure.