Syslog-ng cannot read logfiles, even it is running under root user.
In the logs the following error is shown.
Error opening directory '/app/log': Permission denied'
Example directory permissions:
drwxr-x---. 2 user user 42 may 13 10.19 /tmp/log
The source file and/or directory permissions must be modified using one of the below solution.
a. Add root user to the 'user' group which has read rights. (Change 'user' according to your environment.)
usermod -a -G user root
b. Add permissions to 'other users'.
chmod o+rx /tmp/log
Add the following line to /etc/sysconfig/syslog-ng (RPM) or /etc/default/syslog-ng (DEB), depending on your distribution, then restart syslog-ng.