What the hell is Configuration Management anyway? Martin White Equinox Software Architects August 2005

1. What the hell is Configuration Management anyway?Martin WhiteEquinox Software ArchitectsAugust 2005 ©equinox limited 2005

2. About me • Six years IT industry experience, mainly in the UK • Focussed on designing, implementing, documenting and maintaining Configuration Management practices • Experience of ClearCase, SourceSafe, MKS Integrity, AccuRev • AIT – 500 staff, one product, divergent customer versions • i2 – 250 staff, multiple products all integrated together • Equinox – 40 staff, bespoke development and consultancy ©equinox limited 2005

3. Introduction to CM • This is about Software Configuration Management • SCM really only recently emerging as a widely recognised software engineering discipline • What do you think CM is? ©equinox limited 2005

4. Introduction to CM (cont.) • British Computer Society CMSG Technical and organisational activities comprising configuration identification, configuration control, configuration status accounting and configuration audit. This includes the processes of identifying and defining the Configuration Items, recording and reporting the status of Configuration Items and requests for change, and verifying the completeness and correctness of Configuration Items. ©equinox limited 2005

5. Introduction to CM (cont.) • Brad Appleton, Steve Berczuk, Ralph Cabrera and Robert Orenstein; Streamed Lines: Branching Patterns for Parallel Software Development; 5th Annual Conference on Pattern Languages of Program Design; Allerton Park, IL, September 1998 Software Configuration Management is the process of identifying, organizing, controlling, and tracking both the decomposition and recomposition of: software structure, functionality, evolution, and teamwork. In short, SCM is the "glue" between software artifacts, features, changes, and team members; it forms the ties that bind them all together from concept to delivery and beyond. ©equinox limited 2005

6. Introduction to CM (cont.) • What do I think? SCM is a discipline that uses tools and processes to help changes to be made to software as efficiently as possible, whilst retaining levels of control, reproducibility and traceability appropriate to the organisation in question. • Why define it this way? • Emphasises the ultimate point of SCM • Balances pace of change with accountability • Acknowledges need for processes to be realistic and practical ©equinox limited 2005

7. Introduction to CM (cont.) • Some common misconceptions • SCM equals version control • Version control only applies to code • We’re too small to need CM ©equinox limited 2005

8. Tools • 90% of CM is process NOT tools • BUT tools are necessary to enable processes to work well • CM tools normally cover one or more of the following • Version control • Defect/change tracking • Build management • Workflow ©equinox limited 2005

9. The minimal approach to CM • Maintain a version history of files with important versions identified • Maintain a descriptive list of changes made/planned ©equinox limited 2005

10. The most common approach to CM? • Use a version control tool to maintain a version history of files with important versions identified • Use branching to manage basic parallel development scenarios (maybe) • Maintain a descriptive list of changes made/planned in either a homegrown database or a defect tracking tool • Use unspoken conventions to manage workflow ©equinox limited 2005

11. How can we do better? • Apply patterns • Use a framework (ITIL, CMM) • Employ a consultant to help…?! ©equinox limited 2005

12. How can this be improved (cont.)? • Consider what you want to get out of it (don’t do something because some CM expert says you should) • Automate, automate, automate • Consider the following slides for particular areas to focus on… ©equinox limited 2005

13. Coverage • Version everything you can • If you can’t version it, document it and version the document • Business benefits • Improves reproducibility • Encourages consistency Design docs Env settings Build scripts Testware Documentation Code ©equinox limited 2005

14. Workspaces • Make it really easy to begin working on a project • Allow the user to only see the files they need • Business benefits • Reduces set up time for new staff • Improves reproducibility Documenter Developer Manager Tester ©equinox limited 2005

15. Check-in BUILD MACHINE Builds • Local builds • Integration builds • Fully automated • Build reports • Business benefits • Reduces defect rate • Improves responsiveness • Improves reproducibility • Greater dev team efficiency DEV MACHINE ©equinox limited 2005

16. REL1.1.1 REL1.2 REL1.1 REL1 REL2 Branching strategies • Let your project requirements determine your branching strategy rather than being confined by it • Don’t let branches diverge too far • Business benefits • Technical constraints don’t dictate development activity • Can isolate risky or large changes • Can easily control contents of releases ©equinox limited 2005

17. Integrate to change management tool ©equinox limited 2005

18. CHANGE3 CHANGE4 CHANGE1 CHANGE2 Integrate to change management tool (cont.) • Can easily find the files involved in making any given change • Conversely, for any given file version can see why it was created • Business benefits • Improves traceability • Increases developer productivity VERSION 1 2 3 4 A B FILE C D ©equinox limited 2005

19. Raise abstraction level • In other words, start managing code in terms of changes, not files • Why? Consider this… ©equinox limited 2005

20. Change on main line Change on rel 1 maintenance line Change on rel 2 maintenance line Release and potential branch point REL1 REL3 REL2 REL1.1 REL2.1 REL1.2 Raise abstraction level (cont.) ©equinox limited 2005

21. Change on main line Change on rel 1 maintenance line Change on rel 2 maintenance line Release and potential branch point REL1 REL3 REL2 REL1.1 REL2.1 REL1.2 Raise abstraction level (cont.) ©equinox limited 2005

22. Raise abstraction level (cont.) • In other words, start thinking in terms of changes not files • Much easier to manage complex scenarios • Can avoid whole-branch merges • Business benefits • Much greater control over content of releases • Greater reporting capabilities ©equinox limited 2005

23. ‘Componentise’ • If you have multiple teams sharing code or components you need a defined file sharing procedure • Some tools provide good component management support • But to demonstrate that it is possible in any tool… ©equinox limited 2005

24. Builds ‘Componentise’ Supplier repository Hub repository Client repository Component Use manifest Definition manifest Source files Workspace setup process Workspace ©equinox limited 2005

25. ‘Componentise’ • If you have multiple teams sharing code try to implement a good process for managing this • Some tools provide good component management support • But to demonstrate that it is possible in any tool… • Business benefits • Encourages code re-use • Improves reproducibility and traceability • Contributes to automatic workspace setup ©equinox limited 2005

26. General business benefits • Ensure reproducibility and traceability • Improve customer support • Develop software efficiently • Some clients require conformance to certain standards ©equinox limited 2005

27. Impact of NOT doing CM well • Bugs that were fixed ‘re-appear’ • Inability to find out who made a particular change • Inability to reproduce past releases reliably • No-one is really sure what has changed in the product since the last release • Processes prevent people from doing work they need to do ©equinox limited 2005

28. Further resources • BOOK: “Software Configuration Management Patterns” Stephen Berczuk & Brad Appleton • ONLINE FORUM: CM Crossroads www.cmcrossroads.com • WHITE PAPER: Version Control is not CM http://www.spectrumscm.com/WhitePapers/vcnotcm.pdf • ARTICLE: But I Only Changed One Line of Code! http://www.stsc.hill.af.mil/crosstalk/2003/01/leishman.html ©equinox limited 2005

29. Questions? ©equinox limited 2005

30. Contact • Martin White, Equinox Software Architects • martin.white@equinox.co.nz • 04 494 3728 • www.equinox.co.nz ©equinox limited 2005

31. ©equinox limited 2005