1 ©equinox limited 2005 What the hell is Configuration Management anyway? Martin White Equinox Software Architects August 2005

2 ©equinox limited 2005 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

3 ©equinox limited 2005 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?

4 ©equinox limited 2005 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.

5 ©equinox limited 2005 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.

6 ©equinox limited 2005 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

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

8 ©equinox limited 2005 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

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

10 ©equinox limited 2005 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

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

12 ©equinox limited 2005 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…

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

14 ©equinox limited 2005 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 DeveloperTesterDocumenterManager

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

16 ©equinox limited 2005 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 REL1 REL2 REL1.1 REL1.2 REL1.1.1

17 ©equinox limited 2005 Integrate to change management tool

18 ©equinox limited 2005 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 A B C D FILE VERSION 1324 CHANGE1 CHANGE3CHANGE4 CHANGE2

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

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

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

22 ©equinox limited 2005 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

23 ©equinox limited 2005 ‘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…

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

25 ©equinox limited 2005 ‘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

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

27 ©equinox limited 2005 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

28 ©equinox limited 2005 Further resources  BOOK: “Software Configuration Management Patterns” Stephen Berczuk & Brad Appleton  ONLINE FORUM: CM Crossroads  WHITE PAPER: Version Control is not CM  ARTICLE: But I Only Changed One Line of Code!

29 ©equinox limited 2005 Questions?

30 ©equinox limited 2005 Contact  Martin White, Equinox Software Architects   

31 ©equinox limited 2005