Www.ischool.drexel.edu 1 Server Technologies II Configuration Management INFO 321 Glenn Booker INFO321 Week 4

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Server Technologies II

Configuration Management

INFO 321

Glenn Booker

INFO321 Week 4


Configuration Management (CM)

• Additional references include:– Configuration Management Training

Foundation – International Society of Configuration

Management – IEEE standards (replaced military standards),

such as IEEE 828 (Configuration Management Plans)

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• Need Configuration Management in order:– To define what the product is– To track changes to the product– To help control product integration– (and to meet ISO and CMM standards)

• Helps deliver the product 1) on schedule, 2) within budget, and 3) according to the stated requirements

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• Main functions of CM are:– Configuration Identification– Configuration Control– Configuration Audits– Configuration Status Accounting

• Done properly, CM is almost invisible!

• CM mistakes are often far too visible

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Configuration Items

• Systems are divided into configuration items

• Formal name of major software configuration items may be a “Computer Software Configuration Item” (CSCI)– Scope of each CSCI is selected during high level design

based on: criticality, complexity, interfaces, maintenance needs, functions, source (supplier), and documentation needs

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Configuration Items

– CSCIs may be very broad, such as Software, Hardware, Network, or Documentation

• Computer Software Components (CSCs) are often major functions, such as User Interface, or Application Software

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Configuration Items

• Computer Software Units (CSUs) are single functions, which may still consist of one or more closely-related modules of code

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Naming Configuration Items

• One naming convention for configuration items is the form

aa-bb-ccWhere aa is the CSCI number

bb is the CSC numbercc is the CSU number

• Extremely complex systems might use multiple levels of CSCs (components)

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Configuration Structure Excerpt

01 Application ServerCSCI

01-01 ControllerApplications

CSC

01-02 ExternalInterfaces

CSC

02-01 QueryApplications

CSC

02-01-01 PersonnelQuery

02-01-02 ProductQuery

01-02-02 HR SystemInterface

01-02-03 FDAInterface

01-02-01 FinanceSystem Interface

02 Database ServerCSCI

CSUs ->

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Configuration Identification

• What is the smallest thing controlled and tracked? – Important to define for maintenance

• Answer is called the “Lowest Replaceable Unit (LRU)”– Software: could be a CSU, module, script, etc.– Hardware: chip (CPU), board (motherboard),

box (rack element), or unit level (entire rack)

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• Clarify revision, variation, and version

• Revisions (revised copy of a CI) include changes to the CI due to:– Added functions (new features)– Performance improvement (redesign)– Reduced bugs (bug fix)– Other directed changes

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• Variations - alternate configurations to meet different requirements– Are generally named differently, not

just renumbered – E.g. if different installation sites need

variations on some CIs

• “Version” is a major step in a CI’s evolution– At the product level, Word 2000 versus

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• Each CI is given a unique identifier, and tracked by a version number (2.0) and/or revision letter (A, B, …)

• Old copies are kept:– In case you need “the last version that

worked” – To recreate bugs– To develop metrics for future projects

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• Configuration identifiers are basis for:– Baseline identification– Engineering release– Drawing repository– Document repository– Parts and inventory control

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Configuration Control

• Scope of controlled CIs includes:– Support software (system build files,

compilers, operating system, linkers and loaders, procedure languages, shell scripts)

– Object code– CASE elements, third party tools– Libraries– Project plans...

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– Test plans and procedures– Test data– Documentation– Software Development Folders

(including source code)– CM plans, procedures, and reports– HW platform interfaces– Problem reports

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• Establishes:– Interface management– Asset accountability– Change processes– Baseline control– Non-conformance tracking– Upgrade capability

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Change Types

• Class I - changes to the product’s form, fit, or function (big changes)

• Class II - minor changes

• Why make this distinction? – Might have more extensive review process for

Class I changes, such as cost analysis, expert review, interface impact analysis, etc.

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Change Types

• Can also distinguish between changes to fix the existing system (break/fix) versus changes to implement new features (meet new requirements)

• See sample change control process here and a discussion of possible change relationships

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Configuration Audits

• Audits can be formal or informal, internal or external (e.g. contractual or legal):– Product buy-off (approve first article

off production line)– Assessment (internal audit)– Subcontractor reviews (external)– Functional Configuration Audit (FCA)– Physical Configuration Audit (PCA)

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• Often conduct audits when transitioning from informal to formal control

• FCA is done after product has completed certification testing - determines if product is acceptable to the customer

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• PCA immediately follows FCA - determines what the configuration is, and defines the first official Product Baseline

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Internal Audits

• Review compliance with internal procedures, work flow, and spot checking physical inventory

• Determines whether your CM processes are really being used, or serve as dust-catchers

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Internal Audits

• CM internal audits should be performed by the QA organization

• Results are published, and problems fixed

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External Audits

• External audits may be performed for several reasons:– To prove the quality of your processes

(e.g. ISO 9000, CMM)– To provide legal proof of activities (cost

audits, tax audits)– To prove to the world you really know

what’s going on!– To meet customer requirements

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Configuration Status Accounting

• Enables:– Traceability through configuration changes– Production of metrics– Integrated repository– Automated tool suites– Change chronology

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• Purpose is to convey output of the other CM processes

• Establishes a configuration record

• Provides management metrics

• Tracks proposed changes through implementation

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• Must be able to:– Identify the current configuration– Report status of all proposed

engineering changes– Report status of all configuration audits– Provide traceability among configurations– Track specific configuration identifiers

(e.g. serial numbers)

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Configuration Status Reports

• Baseline Configuration Report

• Software Structure Diagram

• Periodic reports:– Project library and media contents– Outstanding software– Change Request status– Change Summary report

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Management’s Role in CM

• Define organization

• Assign roles and responsibilities

• Identify management representative from CM

• Identify training needs

• Act as conflict resolution authority

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Software-specific CM

• Provides:– Version control– Software documentation– Workspace management– Media vaulting– Development library (reuse and other)– Project visibility

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Baselines During Product Life Cycle

Concept Definition

Requirements Definition

Design, Code, and Test

Production & Operation

End of Life or Archive

Need

Functional Baseline

SDR

SW Allocated Baseline Allocated

Baseline

Product Baseline

SW Product Baseline

SSR CDR FCA/PCA

Time

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Formal Baselines

1) Functional Baseline - describes the key performance and functions of the product - what will it do?– Completed by the end of concept definition,

after successful Software (or System) Design Review (SDR)

– What must this product do in order to be successful?

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Formal Baselines

2) Software Allocated Baseline (SAB) - consists of the Software Requirements Specification (SRS) and Interface Requirements Specification (IRS!)– After the requirements for the product have been defined,

the SAB is released as a result of the Software Specification Review (SSR)

– Full development of the software follows, based on the SAB

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Formal Baselines

• “Allocated” in this context refers to the product’s requirements being allocated, or assigned, to specific parts of the software or system – This defines which functions must be

performed by each portion of the software or system

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Formal Baselines

3) Allocated Baseline - describes how the functional baseline applies to each major area of the product; What does each part of the product do? How do they interact?– Allocated Baseline follows a successful

Critical Design Review (CDR) (well after the SSR)

– Before the CDR, there can be one or more Preliminary Design Reviews (PDR)

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Formal Baselines

• The Allocated Baseline forms the foundation for the remainder of detailed product design and development– If a life cycle model is being used which breaks into

subprojects or stages, that break generally occurs after the Allocated Baseline is defined and approved

• Allocated Baseline essentially marks the end of high level design

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Formal Baselines

4) Product Baseline - describes the final product, including end user, design, and maintenance information– Is first released after development

has been completed, as the product goes into production

– Generally defined at the end of FCA/PCA

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Formal Baselines

5) Software Product Baseline - includes software product specification, Version Description Document (VDD), and the actual software– Is established just after the Product

Baseline and FCA/PCA– Consists of the software-related parts

of the Product

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Formal Baselines

• All of the Baselines will evolve throughout the life of the product– All changes to the system must check for

changes to baselined documentation too

• Software-only projects (no hardware) will simplify to three baselines– Functional, Allocated, and Product

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Software Libraries

• Need at least three levels of libraries:1. Restricted access project archives of each

version (CM control only)

2. Working copies of the current version for day-to-day development and testing, which are checked out to developers

3. Archive storage (disaster planning)

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Library Tasks

• “Check in” software - accept software and documentation

• Store software in a known location

• “Check out” software to authorized users

• Use of check in and check out prevents two people from changing one piece of code at the same time

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Software Developmental Configuration (SDC)

• Consists of all successfully tested and approved software, and approved documentation

• Is stored in Software Development Library

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• Is controlled manually, or with a CM tool– MS SourceSafe, Rational Clearcase,

QVCS, Metrowerks, CVS

• Contains the product baseline at selected moments in time

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• Has restricted access, and sealed media

• Changes only by approval of the Configuration Control Board (or equivalent)– A critical CM concept is to require approval of

all changes to anything which has been baselined (put under CM control)

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Document Control

• A “Release” means that a document is ready for its intended use

• The release process, which is part of Document Control, includes reviewing, validating, storing, maintaining, archiving, and communicating controlled design information

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Version Control

• Tracks initial versions, changes to code, and derived relationships (code splits or merges)

• Version control is needed to define, construct, and manage software configurations; and control product releases

• Each software release is a collection of programs, data, and documents on magnetic media

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Version Description Document

• Describes the software to be released

• Describes approved changes since the last release

• Describes approved changes NOT in this release

• Identifies each software release and its documentation

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Software Control Drawing

• Describes characteristics of executable software, such as the structure of a CSCI, or the relationship between CSCI’s and hardware, e.g.– Interface flow charts– Entity-Relationship Diagrams– Class diagrams– Network diagrams

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CM Tools

• Source Code Control System

• Revision Control System

• Build Management– “Make” tools (to compile software)

• Might include the entire Software Engineering Environment!

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CM Policies

• A Software Standards Manual (SSM) describes the policies and guidelines used by an entire organization

• A Software CM Plan (SCMP) describes how the SSM is implemented on a particular project

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CM Planning

• Describe:– The vision, mission, policy– CM risk analysis– The CM system– Project tailoring– Approach for process improvement

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The CM Plan

• CM Plan should define who, how, and when to:– Conduct CM assessments and audits– Assign configuration identifiers– Conduct configuration audits– Control the baselines – Establish & manage the SDL and software

archive (how to check software in and out)...

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The CM Plan

• CM Plan should define: – Engineering change processes, both for

software improvements (requirements management) and for quality improvement (defect removal)

– Documentation flow and reports

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Key CM Considerations

• Develop and use a CM Plan

• How will configuration items be identified?

• How will configuration items be controlled?

• How will the software and documentation libraries be created and managed?

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Key CM Considerations

• How and when will audits be performed? • What kind of reports will be prepared? • How and when will be baselines

be defined?• How will changes to the baselines be

controlled? (see Change Control Process)

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Documents

Www.ischool.drexel.edu 1 Server Technologies II Configuration Management INFO 321 Glenn Booker INFO321 Week 4