Deployment Confidence is a measure of a change’s likelihood to break the production environment. Some changes are trivial, and after code review and testing have little to no chance of breaking the production system. Other changes, especially when they are sourced from long-lived branches and involve many changes, would be riskier. The higher the risk, the lower the Deployment Confidence is.
It doesn’t take much skill to identify changes that have a high likelihood of breaking production, but it does take some experience. In general, things to look for that should decrease your Deployment Confidence include:
- Many changes made without deployment (thousands of lines of code changed with over 10 non-atomic commits)
- Long-Lived Branches (likely a result of #1)
- Complex database migrations
- Major refactoring
- Environmental Drift:
staging != production != local dev