[dgacmu]

In addition to the other answers you've gotten, it's often the case that: (a) Developing what you need as a modest extension to existing OSS is cheaper than doing it all by yourself; and (b) Contributing those changes back to the community means that you've shed the burden of having to keep your local patch's changes in sync with the OSS version going forward.

("Hey, we wanted to use MAAS to maintain our cluster, but it doesn't support our particular power controller, so let's send the patch upstream...")