16 configuration management.ppt [호환 모드] - rtcc...

Real-Time Computing and Communications Lab., Hanyang Universityhttp://rtcc.hanyang.ac.kr

Real-Time Computing and Communications Lab., Hanyang Universityhttp://rtcc.hanyang.ac.kr

Configuration Management

Minsoo Ryu

Hanyang University

[email protected]

2Real-Time Computing and Communications Lab., Hanyang University

http://rtcc.hanyang.ac.kr 2Real-Time Computing and Communications Lab., Hanyang Universityhttp://rtcc.hanyang.ac.kr

Outline

Introduction SCM Activities SCM Process



Software Configuration Management

Definition A set of management disciplines within a software

engineering process to develop a baseline Software Configuration Management encompasses the

disciplines and techniques of initiating, evaluating and controlling change to software products during and after a software project

Standards (approved by ANSI) IEEE 828: Software Configuration Management Plans IEEE 1042: Guide to Software Configuration Management.



SCM in CMMI

CM is a key process in CMMI Level 1-Initial: ad hoc/chaotic Level 2-Managed: basic project management and

documentation Level 3-Defined: standard and complete process control and

procedures Level 4-Quantitatively Managed: predictable process

performance and precise measurements Level 5-Optimizing: continuous and recursive improvement

to performance

CM operates through the software life cycle



What is SCM Not

Not just version control

Not just for source code management

Not only for development phase

Selecting and using tools are important, but design and management of SCM process are more crucial for project success



Some Simple CM Scenarios

Developer A wants to see latest version of foo.c and its change history since last week

B needs to revert foo-design.doc to its version two days ago

B makes a release of the project and he needs to know what items to include and which version

A lives in New Dehli, India and B lives in Boston, US, they want to work on HelloWorld.java together

In the latest release, a serious bug is found and manager C wants to track what changes caused the bug, who made those changes and when

C wants to get reports about current project progress to decide if she needs to hire more programmers and delay the alpha release



Configuration Management Activities

Software Configuration Management Activities: Configuration item identification Change management Promotion management Release management Branch management Variant management Build management

No fixed order: These activities are usually performed in different ways

(formally, informally) depending on the project type and life-cycle phase (research, development, maintenance)



Configuration Management Activities

Configuration item identification Modeling the system as a set of evolving components

Change management The handling, approval & tracking of change requests

Promotion management The creation of versions for other developers

Release management The creation of versions for clients and users

Branch management The management of concurrent development

Variant management The management of coexisting versions

Build management The management of building executable applications



Configuration Management Roles

Configuration Manager Responsible for identifying configuration items Also often responsible for defining the procedures for

creating promotions and releases Change Control Board Member

Responsible for approving or rejecting change requests Developer

Creates promotions triggered by change requests or the normal activities of development. The developer checks in changes and resolves conflicts

Auditor Responsible for the selection and evaluation of promotions

for release and for ensuring the consistency and completeness of this release.



Configuration Item Identification

Configuration Item An aggregation of hardware, software, or both, designated for

configuration management and treated as a single entity in the configuration management process.

Software configuration items are not only source files but all types of documents Code files Drivers for tests Analysis or design documents User or developer manuals …

In some projects, not only software but also hardware configuration items (CPUs, bus speed frequencies) need to be put under control!




Any entity managed in the software engineering process can potentially be brought under configuration management control But, not every entity needs to be under configuration

management control all the time

Two Issues: What: Selection of Configuration Items

• What should be under configuration control? When: When do you start to place entities under configuration

control?

Choices for the Project Manager: Starting with Configuration Items too early introduces

bureaucracy Starting with Configuration Items too late introduces chaos.




Selecting the right configuration items is a skill that takes practice Very similar to object modeling Use techniques similar to object modeling for finding

configuration items!• Find the configuration items• Find relationships between configuration items



Which Should Be Chosen?

Problem Statement Software Project Management

Plan (SPMP) Requirements Analysis

Document (RAD) System Design Document (SDD) Project Agreement Object Design Document (ODD) Dynamic Model Object model Functional Model Unit tests Integration test strategy

Source code API Specification Input data and data bases Test plan Test data Support software (part of the

product) Support software (not part of the

product) User manual Administrator manual



Possible Selection of Configuration Items

Problem Statement Software Project Management

Plan (SPMP) Requirements Analysis

Document (RAD) System Design Document (SDD) Project Agreement Object Design Document (ODD) Dynamic Model Object model Functional Model Unit tests Integration test strategy

Source code API Specification Input data and data bases Test plan Test data Support software (part of the

product) Support software (not part of the

product) User manual Administrator manual



Configuration Item Tree

Configuration ItemCandidates

Models Subsystems Documents

Object Model Dynamic Model

Database User Interface

. . . .

Code Data Unit Test

RAD ODD

. . . . . . . .

. . . .



Change Management

Change management is the handling of change requests

The general change management process: The change is requested The change request is assessed against requirements and

project constraints Following the assessment, the change request is accepted or

rejected If it is accepted, the change is assigned to a developer and

implemented The implemented change is audited



Version, Revision, and Release

Version The initial release or re-release of a configuration item

associated with a complete compilation or recompilation of the item (different versions have different functionality)

Many naming scheme for versions exist (1.0, 6.01a, …) A 3-digit scheme is quite common

Revision Change to a version that corrects only errors in the design or

code, but does not affect the documented functionality Release

The formal distribution of an approved version

Major, External Release

(Customer)

Minor,Internal Release

(Developer)

Small Revision (Developer)

7.5.5



How Versions are Stored

Full copy of each version Delta (differences between two versions) Forward delta

Reverse delta

Mixed delta

1.1 1.2 1.3 1.4

1.1 1.2 1.3 1.4



Version Control Model

Basic problem of collaborative work




Model 1-Pessimistic: lock-modify-unlock

Problems:

Forget to unlock

Parallel work not possible

Deadlock

(1) (2)

(3) (4)




Model 2-Optimistic: copy-modify-merge

(1) (2)

(3) (4)

(5) (6)

(7) (8)



Baseline

Baseline “A specification or product that has been formally reviewed

and agreed to by responsible management, that thereafter serves as the basis for further development, and can be changed only through formal change control procedures.”

Examples: Baseline A: The API has been completely been defined; the

bodies of the methods are empty Baseline B: All data access methods are implemented and

tested Baseline C: The GUI is implemented



Types of Baselines

As systems are developed, a series of baselines is developed, usually after a review (analysis review, design review, code review, system testing, client acceptance, ...) Developmental baseline (RAD, SDD, Integration Test, …)

• Goal: Coordinate engineering activities Functional baseline (first prototype, alpha release, beta

release, …• Goal: Get first customer experiences with functional system

Product baseline (product)• Goal: Coordinate sales and customer support



Transitions between Baselines

Release

Baseline A (developmental)

Baseline B (functional, first prototype)

Baseline C (product, beta test)

How do we manage changes in baselines?

=> Change Management



Controlling Changes

Two types of making changes Promotion: The internal development state of a software is

changed Release: A changed software system is made visible outside

the development organization

User

ReleaseSoftware

RepositoryMaster

DirectoryProgrammer

Promotion



SCM Directories

Programmer’s Directory (IEEE: Dynamic Library) Library for holding newly created or modified software

entities The programmer’s workspace is controlled by the

programmer onlyMaster Directory (IEEE: Controlled Library)

Manages the current baseline(s) and for controlling changes made to them

Changes must be authorized Software Repository (IEEE: Static Library)

Archive for the various baselines released for general use Copies of these baselines may be made available to

requesting organizations.



Promotion and Release Policies

Whenever a promotion or a release is performed, one or more policies apply The purpose of these policies is to guarantee that each

version, revision or release conforms to commonly accepted criteria

Examples for change policies “No developer is allowed to promote source code which

cannot be compiled without errors and warnings” “No baseline can be released without having been bet-tested

by at least 500 external persons”



Branch Management

In practice, teams of developers work on different features and functionalities concurrently Teams working on related features may find themselves

modifying the same configuration items Branching permits teams to work on the same configuration

item independently• Trunk: a main version, usually also a promotion• Branch: a sequence of version that are later merged back to

the trunk

Branch management deals with the creation and tracking of branches and their subsequent merging Merging process must identify and reconcile conflicting or

interfering changes



Heuristics for Branch Management

Identify likely overlapsMerge frequently with the main trunk Communicate likely conflictsMinimize changes to the main trunkMinimize the number of branches



Variant Management

Variant Versions that are intended to coexist Purposes

• To support the software on different platforms• To customize features for different customers

Two approaches Redundant teams

• Assign one team on each variant• Each variant essentially becomes an independent project• Software base easily diverges• Potential duplication of errors

Single project• Distinguish between common code and variant-specific code during

subsystem decomposition• Some teams maintain the common code while others maintain variant-

specific code• Product build rules assemble the correct pieces for the appropriate

variant



Redundant Teams vs. Single Project



Build Management

The transition from source code to the executable application contains many mechanical steps: Settings required paths and libraries Compiling source code Copying source files (e.g. images, sound files, start scripts) Setting of file permissions (e.g. to executable) Packaging of the application (e.g. zip, tar, dmg)

Executing these steps manually is time-consuming and the chance of introducing failures is high



Build Management

Large and distributed software projects need to provide a development infrastructure with an integrated build management that supports: Regular builds from the master directory Automated execution of tests E-mail notification Determination of code metrics Automated publishing of the applications and test results

(e.g. to a website)



SCM Processes

Change control process Status accounting Configuration audit Release management CM planning



Change Control Process

Submission of Change Request (CR) Technical and business evaluation and impact analysis Approval by Change Control Board (CCB) Engineering Change Order (ECO) is generated stating

changes to be made criteria for reviewing the changed CI

CI’s checked out Changes made and reviewed CI’s checked in



Status Accounting

Administrative tracking and reporting of CIs in CM system

Examples Status of proposed changes Status of approved changes Progress of current version, on or behind schedule Estimate of resources to finish one task bugs identified by configuration audit



Configuration Audit

Independent review or examination to assess if a product or process is in compliance with specification, standards, contractual agreement, or other criteria

Examples Verifies that CIs are tested to satisfy functional requirements Verifies that baseline contains necessary and correct CI

versions Ensures that changes made to a baseline comply with the

configuration status reports



Release Management

Creation and availability of a new version of software to the public

Release format Source code + build script + instructions Executables packaged for specific platforms Other portable formats: Java Web Start, plugins Patches and updates: automatic, manual

Release content Source and/or binary, data files, installation scripts, libraries,

user and/or developer documentation, feedback programs, etc.



Make a CM Plan

Standards IEEE Std 828 (SCM Plans), ANSI-IEEE Std 1042 (SCM), etc.

CM plan components What will be managed (list and organize CIs) Who will be responsible for what activities (roles and tasks) How to make it happen (design processes for change requests, task

dispatching, monitoring, testing, release, etc.) What records to keep (logs, notes, configurations, changes, etc.) What resources and how many (tools, money, manpower, etc.) What metrics to measure progress and success



CM Tools

Version control RCS, CVS, Subversion, Visual Source Safe, Rational ClearCase

Bug tracking Bugzilla, Mantis Bugtracker, Rational ClearQuest

Build GNU Make and many variants, Ant

Project management Sourceforge.net, freshmeat.net, GForge, DForge