How to set global vars?

I create a VM in step 1, and I will use ssh plugin(, so needs step 1 FIP. So we can’t use file pass arguments…

The only way to pass information from one step to the next is using files on disk (either in the workspace or volumes).

Your only option to pass FIP from one step to the next one is using a file, however, unless the plugin appleboy/drone-ssh accepts the host parameter from a file, I think is not possible to do what you want. You could, however, fork the plugin and change it to add the feature of reading host from a file.