'Unable to create the "cache" directory' Runtime Exception After Install

I’m running into the error when first loading the app after what otherwise appears to be a successful install of the demo. OS - Centos 7, PHP - 7.2, MariaDB. As far as I can tell I’ve got the OS bits set up correctly and verified the list of extensions that need to be installed (according to the System Requirements page, at least).

I’m running composer and the install as apache. I get a bunch of “deprecated” messages from composer, but no errors. I get no errors from the installer at all. All of the installed files and directories are owned by apache. Yet, when I try to load the app, I get a red bar with the following error message " Warning: file_put_contents(/var/www/html/pimcoredemo/var/cache/dev/appAppKernelDevDebugContainerDeprecations.log): failed to open stream: No such file or directory". The Runtime Exception that triggers it is the unable to create the cache directory in the title.

Pretty much at wits end here. Can anybody provide some guidance on how to clear this and move on?