Tuesday, 20 November 2012

Introduction To Scrum

This post is an introduction to Scrum, one of the Agile methods to drive software application implementation. Reading this post is a prerequisite to this post.

Concepts

  • Scrum projects deliver software application features iteratively.
  • Each iteration is called a sprint.
  • Scrum projects have 4 stages:
    • Planning - Definition of the vision, budget, and expectations. The first version of the product backlog should containing enough implementation items for the first sprint.
    • Staging - This is the first iteration where the requirements and product backlog created in the planning are refined.
    • Development - It is the set of sprints required to implement the project fully. It ends when the product backlog is empty.
    • Release - The final product is deployed, training is performed, documentation is finalized, etc... The release backlog can be used as the product backlog for the next release of the product.
  • There are 4 main roles in scrum projects: team member, product owner, stakeholders and scrum master:
    • A product owner is a customer representative acting as a single point of contact on the customer side.
    • A stakeholder is anyone having a vested interest in the project, providing information about requirements and participating to the decision process of features to be implemented.
    • A scrum master is a facilitator and single point of contact on the development team side. It is a support function, not a 'controlling chief' role. It is a mix between a team leader and a software engineering role, which does not include people management or profit & lost responsibilities.
    • A team member is a software engineer.
  • Scrum of scrum can be implemented when multiple scrum teams are working on the same large project. Scrum master and product representatives get together.
  • The product backlog is a list of features, use cases, enhancement, defect, etc... to be implemented in the project's forthcoming sprints.
  • The release backlog is the list of features, uses cases, enhancement, defect, etc... which are postponed to the next version of the project (not next sprint).

Practice

  • Spring teams typically do not have more than 7 members.
  • A sprint duration is 30 days.
  • Scrum projects are client-driven. They select the features to be implemented.
  • Each sprint begins with two meetings:
    • The stakeholder meeting, with the scrum master and customer representative to re-prioritize the product backlog and update the release backlog.
    • The product owner and team meeting where tasks are created from the product backlog.
  • Each task must require between 4 and 16 hours of work. Bigger tasks must be subdivided into smaller tasks.
  • The scrum master and product owner check whether there are enough resources to support the efforts required to achieve the sprint and adjust the workload accordingly.
  • Team member pick their tasks and work on their implementations.
  • Each spring finishes with a presentation of implemented features to the stakeholders.
  • Every day, a stand-up meeting (15-20 mins) with the team members and eventually the product owner is organized in front of a white board. The following is discussed:
    • Which tasks have been achieved since the last meeting?
    • Are there new tasks? New requirements?
    • What is blocking? Any impediments?
  • If decisions have to be taken, the Scrum Master should take them quickly, within an hour if possible
  • The Scrum Master should deal quickly with any impediments and communication issues
  • Scrum teams should preferably operate from the same room

Conclusion

As for all Agile methods, the Scrum approach is best suited for new projects created from scratch. Over time, when successive application releases are implemented, the project can slowly transform into a continuous integration or even maintenance project, where less stakeholders input or daily supervision is required. The cogs are well oiled and operate naturally.

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