Servlet Root and Servlet Container Details??

I am attempting to install the webapps on a fresh install of RedHat
7.2. I have not yet installed eDirectory, but am planning on
installing 8.7.0 after I get the webapps installed. (I understand
that if I were to install eDirectory before iManager, I would need todo some additional http port configuration and I'd rather avoid having

to do that if possible)

During the iManager install, I am unsure of what the servlet root is
and where it should be installed. In the Servlet Container Details
dialog box, the "Install" option is grayed-out and it is defaulting to

"Use non-detected servlet container". Did I miss something in my
RedHat install, or is this iManager's normal behavior? I am
relatively clueless on this so any nudge in the right direction wouldbe appreciated. Thanks.

--Patrick