SSSD couldn't load the configuration database [5]: Input/output error.

Issue : 

Cannot start ssd on rhel7 server.

In /var/log/messages:


sssd: SSSD couldn't load the configuration database [5]: Input/output error

Issue Description: 

In our case, This error comes in a centos 7 server where SSSD sevice can no be started. Following Error comes when starting the Service.

 [root@exampleserver log]# service sssd status
Redirecting to /bin/systemctl status sssd.service
● sssd.service - System Security Services Daemon
   Loaded: loaded (/usr/lib/systemd/system/sssd.service; disabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Thu 2018-10-04 20:06:41 CEST; 3s ago
  Process: 86361 ExecStart=/usr/sbin/sssd -i ${DEBUG_LOGGER} (code=exited, status=4)
 Main PID: 86361 (code=exited, status=4)

Oct 04 20:06:41 exampleserver.local systemd[1]: Starting System Security Services Daemon...
Oct 04 20:06:41 exampleserver.local sssd[86361]: SSSD couldn't load the configuration database [5]: Input/output error.
Oct 04 20:06:41 exampleserver.local systemd[1]: sssd.service: main process exited, code=exited, status=4/NOPERMISSION
Oct 04 20:06:41 exampleserver.local systemd[1]: Failed to start System Security Services Daemon.
Oct 04 20:06:41 exampleserver.local systemd[1]: Unit sssd.service entered failed state.
Oct 04 20:06:41 exampleserver.local systemd[1]: sssd.service failed.

Cause:

The file /var/lib/sss/db/config.ldb provided by the package 'sssd-common' may be missing.
  

Solution:
The file /var/lib/sss/*  provided by the package 'sssd-common' may be missing. To Solve this issue we need to follow below steps:

1. Stop the SSSD Service.

# systemctl stop sssd

2. Reinstall the sssd-common package:

yum reinstall sssd-common

3. Then Start the SSSD service.

systemctl start sssd

For CentOS6:

1. Stop the SSSD Service.

# service sssd stop

2. Reinstall the sssd-common package:

yum reinstall sssd-common

3. Then Start the SSSD service.

service sssd start