Where is the UTC timezone in CentOS?
Per IANA's time zone database, Etc/UTC is the specifier for the timezone whose display name is UTC -- that is, it's UTC. So the premise of your question is incorrect.
You should see a list of possible timezones in
ls /usr/share/zoneinfo
at the top level should be UTC. To change the timezone of the server, you need to change (or set) the symbolic link /etc/localtime (after you found the location of UTC in zoneinfo directory above)
rm -f /etc/localtime
ln -s /usr/share/zoneinfo/UTC /etc/localtime
more info