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Posts Tagged ‘Value Stream Mapping

Schedule Constraints in the Devops Triangle

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Last week’s post “The Devops Triangle” demonstrated the extension of Jim Highsmith‘s Agile Triangle to devops. The extension relied on adding compliance to the three traditional constraints of software development: scope, schedule, cost. A graphical representation of this extension is given in Figure 1.

Figure 1: Compliance as the Fourth Constraint in Devops Projects

This blog post examines how time/schedule should be governed in the devops context. It does so by building on the concluding observation in the previous post:

The Devops Triangle and the corresponding Tradeoff Matrix demonstrate how governance a la Agile can be extended to devops projects as far as compliance goes. The proposed governance framework however is incomplete in the following sense: schedule in devops projects can be a much more granular and stringent constraint than schedule in “dev only” projects.

For the schedule constraint in devops, I propose a schedule set.  It consists of  four components:

  • Lead Time or Engineering Time
  • Time to change
  • Time to deploy
  • Time to roll back

Lead Time/Engineering Time: These are customary metrics used in Kanban software development, as demonstrated in Figure 3.

Figure 3: The Engineering Time Metric Used by the BBC (David Joyce in the LSSC10 Conference)

Time to change: The amount of time it takes for the various stakeholders (e.g., dev, test, ops, customer support) to review the code to be deployed, approve its deployment and assign a time window for the deployment.

Time to deploy: The amount of time from (metaphorically speaking) pushing the Deploy “button” to completion of deployment.

Time to roll back: The amount of time to undo a deployment. (Rigorous that the engineering practices and IT processes might be, the time to roll back a deployment can’t be ignored – it is a critical risk parameter).

A graphical representation of these four schedule metrics together with the Devops Triangle is given in the figure below:

Figure 4: The Devops Triangle with a Schedule Set

Using hours as the common unit of measure, a typical schedule set could be {100, 48, 3, 2}. In this hypothetical example, it takes a little over 4 days to carry out the development of the code increment; 2 days to get approval for the change; 3 hours to deploy the code; and, 2 hours to roll back.

Whatever your specific schedule numbers might be, it is highly recommended you apply value stream mapping (see Figure 5 below) to your schedule set. Based on the findings of the value stream mapping, apply statistical process control methods like those illustrated in Figure 3 to continuously improving both the mean and the variances of the four schedule components.

Figure 5: An Example of Value Stream Mapping (Source: Wikipedia entry on the subject)

Between Agile and ITIL – Part II

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The July 2009 post Between Agile and ITIL introduced the application of Agile principles to system management with the following words:

You do not need to be an expert in Value Stream Mapping to appreciate the power of speeding up deployment to match the pace of Agile development. By aligning development with deployment, you streamline “production” with “consumption.” The rationale for so doing is aptly captured in the first bullet of the Declaration of Interdependence: “We increase return on investment by making continuous flow of value our focus.”

Yesterday’s press release about the acquisition of Phurnace by BMC validates the projection given in the afore-listed post. Colleague and friend Michael Cote puts his finger on the heart of the acquisition in his post in People Over Process:

The interesting part is also that this is automation – I’m assuming – at the application layer, where as most automation talk in past and present is at the infrastructure layer. Of course, the thought leaders in this area – folks like Reductive Labs (Puppet),OpsCode (Chef), and in a more general sense cloud management outfits – are doing a helpful job of blurring the distinction between traditional IT layers like application and infrastructure with their dev/ops angled automation. Check out this white paper done by Reductive Labs and dto solutions on the topic for a nice toe-dip. And, I’d expect to see more application layer automation from VMWare/SpringSource. Older automation portfolios like BMC’s Blade Logic line need to keep a close eye on these developments, hopefully, taking in the proven parts of that work.

One can, of course, automate IT tasks without embracing Agile. The fundamental question to be answered is whether one considers ITIL as an “empirical” process control model or as a “defined” process control model (or possibly a hybrid).

Between Agile and ITIL

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You do not need to be an expert in Value Stream Mapping to appreciate the power of speeding up deployment to match the pace of Agile development. By aligning development with deployment, you streamline “production” with “consumption.” The rationale for so doing is aptly captured in the first bullet of the Declaration of Interdependence:

We increase return on investment by making continuous flow of value our focus.

As pointed out in previous posts in this blog, Flickr and IMVU seem to be doing an exceptionally fine job streamlining the flow of value: every thirty minutes and every nine minutes respectively. A recent presentation in Velocity 2009 by John Allpsaw and John Hammond adds color how development and operations at Flickr cooperate to accomplish “10+ deploys per day.”

What does such fast pace mean to the business? In a nutshell, much of the guess work as to what features are really needed is eliminated when you develop, deploy and collect customer feedback in ultra fast manner. Consequently, the company’s business design is likely to be transformed. Click here, here, and here for more detailed discussions how the business design gets transformed.

Michael Cote, Andrew Shafer and I have been pondering  about aligning development and operations for quite sometime. On the one hand, we are painfully aware of the traditional desire to minimize change in IT operations. On the other hand, we are of the opinion Agile principles are quite applicable to operations. We often wonder whether the obstacles between Agile and ITIL are real or imaginary. We actually believe the {development –> operations} theme is an important instantiation of Dean Leffingwell‘s recent thoughts about applying Agile/Lean principles to other knowledge work.

The three of us – Michael, Andrew and I – decided to do a few podcasts to explore what stands between Agile and ITIL. The first of these podcasts will be published this month (July 2009).

Stay tuned…

Written by israelgat

July 7, 2009 at 7:19 am