Similar to building software, tools should be used to deploy production server updates (whether DB, website, router configurations, etc). The use of tools reduces certain types of human error (missed steps for example).
- What tools are available for software/configuration/etc deployment (whether free or commercial)?
- List a single tool per post
- What part of the deployment process it performs
- Particular advantages or disadvantages to using this tool (ie, .NET only, supports all LAMP/WAMP platforms, etc)
Don't add a tool that already exists - add comments if you have something particular to say about a given answer.