I worked in a small team of 6 or so on a web application running in a company data centre, 2 people in the team were doing nearly all the work of implementing d

I worked in a small team of 6 or so on a web application running in a company data centre, 2 people in the team were doing nearly all the work of implementing deployment automation & rearchitecture to migrate the app into AWS. They both got good job offers from different companies and quit within about a month of each other, shortly before we were scheduled to migrate production. Fun times! I was happy they'd both found better jobs. Before they left there were lots of knowledge transfer sessions with the team all in a room for a few hours diving through all the layers of all the automation, trying to understand how it fit together, and what the design constraints were. It could have been much worse: enough lead time to do some knowledge transfer and bring rest of team up to speed, none of the technology involved was proprietary, everything was reasonably standard mix of open source automation approaches + AWS, so plenty of access to documentation or working examples from outside of the project. In ended up okay in the end but it's still a small bit of data that perhaps you don't want 2 people in the team with specialist knowledge, more than two would be even better.