How to get env var from one VM and pass it to another VM in Vagrantfile?

Question

Would like to create three VMs using Vagrantfile.

Provisioning for VM#1 (first in sequence) runs a shell script (inside the guest) which prints a secret-token. I would like to "automatically" (i.e. through Vagrantfile) retrieve that secret-token generated while provisioning VM1, and pass it as an argument to provisioning scripts of VM#2 and VM#3. Is this possible ? If so how ?

Please note that I can very well create the 3 VMs, but extracting the secret-token from VM1 (automatically i.e. in the process of running vagrant up) and passing it to provisioning logic of other VMs is all I am missing.

Answer 1

Apparently the above cannot be achieved, using environment variables directly but only by using files and file/exchange between guest and host. The methods are described in this SO answer.