I’m sure there are lots of howtos on the Internet for this, but…
Say you are running a web server like nginx and your log files are in a non-standard location, you may have problems starting the service because SELinux is blocking nginx from reading or writing to the files.
You can set the context of these files so that nginx will be happy:
[user@server ~]$ sudo chcon -Rv --type=httpd_log_t /srv/mydomain.com/logs/
That’s only temporary however, and the original context will be restored if you run restorecon or relabel your filesystem.
So you can do this permanently using the semanage command, like so:
[user@server ~]$ sudo semanage fcontext -a -t httpd_log_t "/srv/mydomain.com/logs(/.*)?"
Now you can use the standard selinux command to restore the correct label and it will use the new one you set above.
[user@server ~]$ sudo restorecon -rv /srv/