I have been setting up a lot of virtual machines for different projects I'm working on. Instead of using ssh-keygen on each machine, I've been copying my id_rsa file from one of my machines to all the other ones I've been setting up.
This way I don't need to upload my rsa_id.pub for each new machine to my server or add them to other servers I want to ssh into.
Is this practice a terrible idea? Should I just be generating a new key for each VM?