Just had the interesting experience of a trivial typo that the type checker couldn't catch de-provisioning a total of 7 containers spread across 3 hosts. Right down to scrubbing the images.

Oh well, I can re-provision automatically. Just a matter of fixing the typo..

- (as . getAttr p)
+ (getAttr p . as)

... and waiting for rather a lot of apt-getting.

It's time for either QuickCheck or a non-production branch, I think...