I'm still lost. You said at the top that you need the VMs to survive across build steps (I read that as jobs), but now they're per-job? The Concourse->Jenkins

I'm still lost. You said at the top that you need the VMs to survive across build steps (I read that as jobs), but now they're per-job? The Concourse->Jenkins thing will definitely happen without better docs, examples and widespread understanding. Concourse is non-obvious to newbies and the error messages need a lot of love. Or any love. I don't quite understand the parenthetical, could you elaborate?