That did the trick. I was sifting through vagrant's source code to see what they were doing. Nice find.

```
><> make pull
for host in 172.17.8.100 ; do ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -t core@$host 'for c in builder cache controller database logger registry router; do docker pull deis/$c; done'; done
Warning: Permanently added '172.17.8.100' (RSA) to the list of known hosts.
Warning: Permanently added '172.17.8.100' (RSA) to the list of known hosts.
Pulling repository deis/builder
3906a1f7175b: Pulling dependent layers
3906a1f7175b: Download complete
6170bb7b0ad1: Download complete
```