Anything that rolls out a text file (like /etc/aliases), should refuse to proceed if more than x% is being changed (catches accidental partial deletes)

• Anything that rolls out a text file (like /etc/aliases), should refuse to proceed if more than x% is being changed (catches accidental partial deletes)
• Just like unittests, make sure new config files have proper syntax and the intended behaviour before they get rolled out
• Back in the day, I wrote a DNS/bind config edit system that spun a test bind with the new config files, scanned logs for warnings and errors, and did test queries against it before the new config file was allowed to be checked in and rolled out (functional unittest with real parser instead of mocked one)

Percent rollouts / Safe file updates