When it comes to the question of "which version" of Linux that is a very broad question. It could mean - depending on the context - "which distribution", or it could mean "which release of distribution XYZ", and it might mean one to the questioner, and the other to the respondent. Better to ask the precise question you actually need to answer. Are you asking "which distro" or "which releases" of a specific distro? If you really are asking the broader question, then the precise answer would be a huge spreadsheet.
If the machine is capable of running an installation Splunk it is almost certainly capable of running the Splunk app, because the app consists of some generic Splunk configuration incorporating some user configurable file paths (although user configurable) augmented by pretty much standard GNU/Linux system tools (such as df and iostat).
