While all the other answers just say "It's a violation of the Photoshop EULA!" lets actually take a look.
First in the section
1.Definitions we need to clarify a few things (page 106 for the US English version) so we can understand the further sections.
"Computer" means a virtual or physical computer device that accepts
information in digital or similar form and manipulates it for a
specific result based on a sequence of instructions
"Internal Network" mean a private, propietary network resource accessible only by employees and individual contractors (i.e., temporary employees) of a specific corporation or similar buisness entity. Internal Network does not include portions of the Internet or any other network community open to the public, such as membership or subscription driven groups, associations, and similar organizations.
"Output File" [...]
"Permitted Number" means one (1) unless otherwise indcated under a valid
license (e.g., volume license) granted by adobe.
Emphasis mine. So if we have multiple copies of the VM running it is considered multiple "Computers", good to know.
Section 2.2 (pg 107 for English)
2.2 General Use. Execpt as described otherwise herein, you may install and use one copy of the Software in accordance with the Documentation
only on the Permitted Number of your compatible Computers into which
you enter a valid serial number.
Drat, so we can't run the VM multiple times as that would count as mutiple computers. Hey, what if we installed in on somthing like Windows Server, where multiple people can be logged in at the same time on the same computer.
2.2 does not mention anything about that! (This "Server" solution is what the guy is doing in the link you posted in your original question)
Section 2.4 (still pg 107)
2.4 Server Use. You may install the Software on the Computer file server(s) within your Internal Network only for the use of the
Software initiated by an individual from a Computer within the same
Internal Network only as permitted by Section 2.1 or 2.2 (as
applicable). The total nubmer of users (not the concurrent number of
users) able to use the Software on such Computer file server(s) may
not exceed the Permitted Number.
Damn, they still got us. Also its good to know that you need a license for every user who will be using the program, not just the number of people using it at the same time (This in the software industry is called Per User licensing vs Per Seat licensing)
So it appears that your idea will not work and indeed it really is "a violation of the Photoshop EULA".