Virtual or physical?

To write low-level scripts, as an admin, you need to know whether you are currently on a physical or a virtual machine. Charly finds out with a couple of clever hacks.

Of the systems I work on, about 90 percent are virtualized and 10 percent are legacy hardware servers. For many jobs, this makes no difference, but when I write scripts that call or change hardware-related functions, I need this information.

If I have root privileges on the system and am also allowed to retroactively install software, the problem can be solved very quickly. I install either Facter [1] or virt-what [2]. Facter provides extensive information about the system’s hardware, much like lshw, and is actually overkill for answering the “virtual or not” question. Calling facter virtual returns the virtualization platform as the answer, such as vmware or kvm. The same result is returned by a call to virt-what. If I don’t need the power of Facter elsewhere, I prefer the leaner virt-what.

If I have root privileges but am not allowed to install software (for example, because of restricted repositories), there is another possibility. The command

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