AGPL license as a system vendor


New Member
Jun 30, 2020

I am part of a company selling turnkey systems which includes servers and various proprietary softwares (some ours, some purchased) running on Windows VMs, and we are looking at Proxmox as a potential replacement for our current solution.

We are not sure what the AGPL entails in our case. My understanding per is that, as we are running our software unrelated to Proxmox on a guest, we should not have to distribute the proprietary code, and merely disclose the AGPL software license. My colleague argued that because we are selling a system with hardware and software, we would have to distribute said proprietary code.

Does anyone have a definitive answer on this topic or should I involve legal ?

Thank in advance !


Proxmox Staff Member
Staff member
Jul 28, 2015
South Tyrol/Italy

First off, IANAL, but I have some certainty that I understand the GPL and AGPL decently and why the second exists in the first place.

If you use Proxmox VE as is, and your proprietary software just runs in guests (VMs or CTs) you do not need to license that software as AGPLv3, or compatible. This could be compared to proprietary code running in an AGPL open run-time (like, for example, a java run-time) - any runtime changes would need to be disclosed, but the program itself not as long it just uses the public ABI/API of that runtime. That's why one can also distribute programs which are using the public Linux syscall interface without disclosing the source.

But, if you make modifications to Proxmox VE itself and host any service with that, you need to redistribute the changes made and disclose this to anyone using the service. I.e., you cannot just switch some logo and a bit of style sheet code, then play commercial hoster using this modified version as interface for customers without releasing those changes and/or without denoting that it runs effectively a (lightweight) fork of Proxmox VE, copyright and AGPL license information.

running our software unrelated to Proxmox on a guest
So, from what I can tell from this described use-case, you should fall into the first category - either not modifying Proxmox VE at all or at least not have those modifications being direct part of your customer experience (if you need to modify it going upstream can often be the better and, for the ecosystem, healthier way).

Note also that doing REST API calls from any program, proprietary or not, is fine. Accessing an API over HTTP(s) can hardly seen as derivative work, after all.

TLDR; programs running in virtual guests are fine to be whatever, deriving Proxmox VE and hosting that not so (without staying in the clear with the AGPLv3).
You're probably clear as long as you follow the rules regarding distribution - but, personally speaking, I can for sure not give my word without a) knowing the specific use case in full detail b) possibly even then still consulting the FSF or the Software Freedom Conservancy if it had to count.

For discussing this in more detail and getting a more definitive answer, it'd be best to write a mail to
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New Member
Jun 30, 2020
Cheers for the speedy and thorough answer!

I do plan on sending an email with specifics through the proper channels to have an official statement that would reassure upper management as well. I just felt like it would be an interesting forum post as my previous online searches on the subject have yielded little for it being an apparently niche situation.

Thanks again !


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