Docker (and containerized Plone/Volto) on virtual machines

I'm not sure whether I understand the legal terms of Docker regarding its use on virtual machines.

As far as I understand it, Docker's general license limitations do not allow to use Docker on virtual machines without a (rather expensive) business license.

Since Plone's main installation strategy relies on containers, those license limitations are relevant for the Plone community and might lead to consider including additional intallation strategies for Plone.

Does anyone have legal expertise on licenses?

See the following quotes of the Docker Subscription Service Agreement.

4.1 General License Limitations.
(b) Under the terms of this license, you shall not, and shall not encourage any third party to: [...]
(vii) use the Service on virtual machines without a license to Docker business for such use; [...]

Service beeing defined as follows:

1. Definitions
"Docker Subscription Service” or the “Service” refers to the applications, software (including any Open Source Software), products and services provided by Docker, including any beta or trial versions.

Only if you use Docker and you are not in a Small Business Environment . See section 4.2 of the agreement.

If you are, you'll either have to use a different container tech (for example Podman) or pay up as you have more than 250 people and $10M in revenue.

As far as I understand, 4.2 (Specific License Limitations – Docker Desktop) adds further restrictions to the Docker Desktop component of the Service at the level of the Personal Offering without overriding 4.1 (General License Limitations).

Do I miss something?

Here is an overview of the various "subscriptions" Docker (the company) offers: Docker subscription overview and here's and more descriptive version Docker is Updating and Extending Our Product Subscriptions | Docker .

But I guess that this only applies if you actually take out a subscription with Docker the company.

I think I've read this correctly, though unsure if I did.

AFAICS those links do not mention virtual machines at all.

The exclusion of the use of virtual machines in point 4,1.b (General License Limitations) makes me feel very uneasy.

I don't know - I outlined what I thought was correct, but someone else might know what's what.

Have you tried contacting Docker and ask?

There is already a post in "Docker Community Forums":

And a comment of the OP in Stackoverflow:

See the comments there.

But it is not yet clarified whether a license is needed or not.

Docker can shout whatever they want, I don't believe it applies to running the containers.
The docker engine stuff is licensed as open source: Docker Engine overview

Please contact Docker directly to make sure what is what. Don't wait for their community forums plus when you have an answer please post it to said forums and this.

Good luck and have fun!