Searching for a locking/reservation tool for our team

Hi! I'm searching for a tool which allows my team members to lock resources for their work.

Specific case: We have two test environments, and more than two team members. Everytime you need a test environment, you have to ask all the other team members, if and which one is in use at the moment.

It would be cool to have a software, which allows us, to lock one system for your own with one simple click, and to see on one view which system is in use at the moment by which person.

Slack integration would be nice.

I don't have any idea how to call such a tool, and what to search for. Is there any software supporting this?