in reply to Re^4: Running a perl 5.8.6 CentOS 6-compiled app on a CentOS 8 platform
in thread Running a perl 5.8.6 CentOS 6-compiled app on a CentOS 8 platform
I believed that one can install multiple versions of some library in linux using a package manager but that does not look possible on closer but still diagonal look. I mention this because a lot of system packages may require the latest libnsl (assuming 1.0 is not the latest) and so by having the package manager installing an older version you keep the system not up-to-date. So, assuming 1.0 is not the latest, you can manually fetch and compile libnsl_1.0 and then copy libnsl.so.1.0 to the system-wide library path and also make a link to libnsl.so.1 BUT do not modify any other links (notably libnsl.so -> libnsl.so.2). In my system dnf has superceded yum btw.
You mentioned that ESE requires Apache server. Is that because it provides a web-API to interact with it? If one can communicate with ESE using http or REST then things can become much simpler. You dedicate a Centos6 machine to ESE and talk to it using your up-to-date centos8 from inside the firewall. I don't know how this will play with security when ESE crawls the web. And still centos6 will someday pack up unsupported.