Ubuntu MAAS to provision servers - when new server arrives guys at the DC just need to plug it in and power it once, everything else is just clicking around. Pyinfra to manage and install software (I'm fed up with custom DSLs, pyinfra is pure python)
Does the dc provide racking servers for you as a service? Or do you have to go out to the dc?
Yes, DC provides racking servers, plugging in cables etc. I just write instructions in a ticket.
I go to the data centre from time to time, mostly taking junior engineers for a sightseeing trip to show them how "the cloud" actually looks :-)
If you need colocation in London I can put you in touch.