The basic idea behind DevOps
is that your development strategy and operations strategy should reflect one another, that you should strive to optimize the whole IT process. This implies that development teams should work closely with your operations staff to deliver new releases smoothly into production and that your operations staff should work closely with development teams to streamline critical production issues.
DevOps has its source in agile software development, and it is an explicit aspect of the Disciplined Agile Delivery (DAD)
process framework. As a result there is a collection of agile development strategies which enable effective DevOps throughout the agile delivery lifecycle. These strategies include:
- Initial requirements envisioning. Disciplined agile teams invest time at the beginning of the project to identify the high-level scope in a light-weight, collaborative manner. This includes common operations requirements such as the need to backup and restore data sources, to instrument the solution so that it can be monitored in real time by operations staff, or to architect the solution in a modular manner to enable easier deployment.
- Initial architecture envisioning. Disciplined agile teams will also identify a viable architectural strategy which reflects the requirements of their stakeholders and your organization’s overall architectural strategy (hence the need to work closely with your enterprise architects and operations staff). One goal is to ensure that the team is building (or buying) a solution which will work well with the existing operational infrastructure and to begin negotiating any infrastructural changes (such as deploying new technologies) early in the project. Another goal is to ensure that operations-oriented requirements are addressed by the architecture from the very start.
- Initial release planning. As part of release planning the disciplined agile team works closely with their operations group to identify potential release windows to aim for, any release blackout periods to avoid, and the need for operations-oriented milestone reviews later in the lifecycle (if appropriate).
- Active stakeholder participation. Disciplined agile teams work closely with their stakeholders, including both operations and support staff, all the way through the lifecycle to ensure that their evolving needs are understood.
- Continuous integration (CI). This is a common technical agile practice where the solution is built/compiled, regression tested, and maybe even run through code analysis tools. CI promotes greater quality which in turn enables easier releases into production.
- Parallel independent testing. For enterprise-class development or at scale, particularly when the domain or technology is very complex or in regulatory environments, disciplined agile team will find they need to support their whole team testing efforts with an independent test team running in parallel to the development team. These testing issues often include validation of non-functional requirements – such as security, performance, and availability concerns – and around production system integration. All of these issues are of clear importance for operations departments.
- Continuous deployment. With this practice you automate the promotion of your working solution between environments. By automating as much of the deployment effort as possible, and by running it often, the development team increases the chance of a successful deployment and thereby reduces the risk to the operations environment. Note that deployment into production is generally not automatic, as this is an important decision to be made by your operations/release manager(s).
- Continuous documentation. With this practice supporting documentation, including operations and support documentation, is evolved throughout the lifecycle in concert with the development of new functionality.
- Production release planning. This is the subset of your release planning efforts which focuses on the activities required to deploy into production.
- Production readiness reviews. There should be at least one review, performed by the person(s) responsible for your operations environment, before the solution is deployed into production. The more critical the system, the more product readiness reviews may be required.
- End-of-lifecycle testing. Minimally you will need to run your full automated regression test suite against your baselined code once construction ends. There may also be manual acceptance reviews or testing to be performed, and any appropriate fixing and retesting required to ensure that the solution is truly ready for production.
There’s more to it though than simply adopting some good practices. Your process must also embrace several supporting philosophies. The Disciplined Agile Delivery (DAD)
process framework not only adopts the practices listed above, and more, but it also promotes several philosophies which enable DevOps:
- Delivery teams should be enterprise aware, that they should work with people such as operations staff and enterprise architects to understand and work towards a common operational infrastructure for your organization.
- Operations and support people should be recognized as key stakeholders of the solution being worked on.
- The delivery team should focus on solutions over software. Software is clearly important, but we will often provide new or upgraded hardware, supporting documentation (including operations and support procedures), change the business/operational processes that stakeholders follow, and even help change the organizational structure in which our stakeholders work.
- Your process should include an explicit governance strategy. Effective governance strategies motivate and enable development teams to leverage and enhance the existing infrastructure, follow existing organizational conventions, and work closely with enterprise teams – all of which help to streamline operations and support of the delivered solutions.
For more detail about this topic, I think that you will find the article I wrote for the December 2011 issue of Cutter IT Journal entitled “Disciplined Agile Delivery and Collaborative DevOps
” to be of value.
In November 2011 Paul Gorans, the Accelerated Solution Delivery (ASD) practice lead in IBM GBS, and I ran an agile adoption survey
. The survey explored a range of issue, including the factors that appear to be associated with the success and failure of agile project teams. Paul wrote up his thoughts in his Agile State of the Art Survey
article on ibm.com and I did the same for Dr Dobb's Journal in Agile Success Factors
. This blog posting summarizes the results of the survey.
Factors which appear to accelerate agile adoption include:
- People are assigned to a single team
- Development teams have easy access to business expertise
- Development teams are organized for agile delivery (not traditional)
- Your organization has an agile support group/community of excellence
- Your organization is explicitly addressing barriers to agility
- There is executive sponsorship for agile
- Agile teams are measured on value creation
- Your organization's IT governance strategy includes an agile path
Factors which appear to decelerate agile adoption include:
- Agile teams are measured using traditional metrics
For some reason, it seems as if everyone's grandfather at one point in time recommended to use the right tools for the job. That's practical wisdom from my point of view, one that is certainly an issue for agile development.
One of the primary messages, I hope, of the Agile Scaling Model (ASM)
is that context counts. Although the focus of the ASM is on describing a contextual framework for tailoring your process to meet the needs of the situation that you find yourself in, it's also applicable to your tooling selection. For example, the tool choices of a co-located team will be much different than that of a geographically distributed team. A co-located team will likely use a whiteboard
or paper for their agile modeling
efforts, whereas distributed team members may need to capture their diagrams using a more sophisticated tool such as Rational Requirements Composer (RRC)
so that their work can be shared electronically. Having said that, RRC would be overkill for a co-located team (unless they had regulatory compliance issues). Different teams, different situations, therefore different tooling choices.
One of the concerns that I run into from customers is that some of our legacy products don't support agile very well. Once again, it's a matter of context because many of our legacy products reflect the realities faced by more traditional teams. The challenge occurs when you try to take a legacy product which is well suited for traditional development, such as Rational ClearCase
, and try to apply it on agile projects. Although ClearCase makes sense in certain scaling situations, particularly very large teams that are geographically distributed, you'd be better advised to use something like Rational Team Concert (RTC)
for configuration management on most agile teams (note that RTC does far more than just SCM).
So, if you're taking an agile approach you should consider Rational tools such as RTC, RRC, Rational BuildForge
, Rational AppScan
, and others which support agile
development. Granted, some you would only use at scale -- for example Buildforge is a good option in really complex environments, but if you don't face that complexity then you'll likely find that RTC's build engine is sufficient. Similarly, if you're taking a traditional approach to development then you'll likely consider products such as ClearCase, Appscan, RTC, and Rational Software Architect (RSA)
instead. Different situations, different tooling choices.
What's even more confusing is that some products support a range of process paradigms. For example, RTC supports agile, lean, iterative, and traditional approaches to development. The same can be said of Appscan and several other products. Notice how I listed RTC and Appscan for both agile and traditional development above.
So, if anyone tells you that Rational tools don't support agile development don't believe them. Ask them which tools that they're talking about, and ask them if they're aware of the Rational products that do support agile development. Context counts.
A common misunderstanding about agile software development approaches are that they're only applicable to small, co-located teams. Yes, it's much easier to be successful with small teams, and with co-located teams, and as a result agilists being smart people prefer to work this way. After all, why take on extra risk when you don't need to do so? But, sometimes reality gets in the way and you find yourself in a situation where you need a large team, or you need to distribute your team (see previous blog postings for strategies for distributed agile development), and you would still like to be as agile as possible. The good news is that it's still possible to be agile with a large team, although you will need to go beyond some of the popular "agile in the small" strategies to succeed.
Here are some disciplined agile strategies to succeed at large-team agile:
- Question the need for a large team. Many times an organization will believe that they need a large team because their process is overly complex, because they're still organized for waterfall development, or simply because that's what they're used to. I've seen teams of 80 people doing the work of 20 as the result of over-specialization of job roles and all the bureaucracy required to organize and validate their work.
- Do some initial envisioning. In order to succeed the team must work together towards the same goals. This is true for small teams but doubly true for larger ones -- without a common vision chaos will quickly ensue. You must gain this common vision on two fronts: you need a common business vision and a common technical vision. To gain the common business vision you must do some initial, high-level requirements envisioning and to gain the common technical vision some common architecture envisioning. This isn't to say that you need to take on the risk of detailed, up-front specifications but you must at least have a high-level understanding of the scope and technical solution in order to move forward effectively. So, expect to spend the first few weeks of your project doing this initial modeling.
- Divide and conquer. You never have a team of 200 people, instead you have a collection of subteams that add up to 200 people. This is called having a team of teams.
- Align team structure with architecture. The most effective way to organize the subteams is to have each one implement one or more components, and thereby to build your overall system as a "system of systems". This reduces the coordination required because the majority of the communication will be within the subteams themselves. You'll still need to coordinate the subteams, that will never go away, but you can reduce the overhead (and the risk) by being smart about the way that you organize the people. A common mistake is to organize around job function (e.g. having architects in Toronto, developers in Raleigh, testers in Bangalore, and so on). This increases communication overhead and risk because these people need to work together closely to get something built.
- Project management coordination. Each subteam will have a team lead/coach, and these people will need to coordinate their work. There is often an overall project manager who leads this group. To coordinate the work within their subteam the team lead/coach will often have a daily meeting, in the Scrum method this is called a scrum meeting, where people share their current status and identify any problems they may be running into. To scale this effectively the team lead/coach attends a daily team coordination meeting, a scrum of scrums, where the same sort of information is shared at the overall team level.
- Product owner coordination. Similarly, each subteam has a product ownder, also referred to as an "on-site customer", who is responsible for making decisions about the requirements and for providing information to the team in a timely manner. Sometimes a single product owner will work with several subteams. The product owners will get together at the beginning of the project to do some requirements envisioning to identify the initial scope and to start portioning the requirements between the subteams. Because the requirements between the subsystems are interrelated and should be reasonably consistent, the product owners will need to meet on a regular basis to share information, to negotiate priorities, and to resolve requirements-related disputes.
- Architecture coordination. Each subteam will have an architecture owner, often a senior technical person and sometimes also in the role of the team lead/coach. These architecture owners will get together at the beginning of the project to do some initial architecture envisioning, based on the requirements envisioning efforts of the product owners. They will identify the major subsystems, and their interfaces, enabling the effective organization of the team into smaller subteams corresponding to the architecture. They will also get together regularly to evolve the architecture and to resolve any major technical issues.
- System integration team. For complex systems, which is often what large teams work on, an effective system integration effort is critical to your success. Although this may be easy at first, as the overall system evolves the need for a subteam focused solely on this quickly becomes apparent. This not only supports the development efforts of the subteams, it also supports independent investigative testing.
- Independent testing team. An independent testing team is common on mid-to-large size agile projects to enhance the testing efforts of the development subteams. This testing team will work in parallel to the developers, they get a new build on a regular basis (minimally each iteration, although more often is desirable), which they test in more advanced ways than what is typical with Test-Driven Development (TDD). For example, they often validate non-functional, quality of service (QoS) type requirements as well as technical constraints, things that often aren't captured well via user stories. They'll also do investigative testing to try to break the system by using it in ways not thought of by the product owners.
- Some specialties reappear. On larger teams it can make sense to have some people be a bit more specialized than what we normally see on small agile teams. For example, it's common to see people in the role of agile DBA, tech writer, build master, or user experience (UE) professional. More complex systems often require people in these roles, although it still behooves these poeple to not be pure specialists but instead to be generalizing specialists with a wider range of skills. Also, recognize that the reintroduction of specialists can be a slippery slope back to the bureaucracy of traditional software development.
When it comes to testing on agile projects it is common practice for agile teams to adopt a "whole team testing
" approach where the team itself does its own testing. To accomplish this agile teams will often embed testers in the development team. Programmers will work closely with the testers, often via non-solo development
strategies such as pair programming, to pick up their valuable testing skills. The testers will in turn pick up new skills from the programmers, and in effect both groups will move away from being just specialists (testers or programmers) to being what's called generalizing specialists
. Whole team testing can be very different from traditional approaches where programmers may do some testing, often unit testing of their own code, and then throw it over the wall to testers and quality assurance (QA) professionals for verification and validation.
The types of testing that the parallel independent test team performs may include:
Pre-production system integration testing. Does the solution work within your overall organizational ecosystem? Importantly, if this is one of several teams currently developing new solutions, does this team's solution work with what will be in production (including the work in progress of other teams) when they go to release? In mid-to-large organizations the only economical way to do this sort of testing is via an independent, centralized team.
. Although it's possible to do usability testing on the development team, the reality is that usability testing is a specialized skill that few people have (although could pick up via non-solo development). Furthermore, particularly for solutions with many potential users, you may want to invest in a usability testing
lab. This is a centralized resource, or an outsourced resource these days, which is shared across many teams.
. Security testing is also a specialized skill, albeit one well supported with sophisticated security testing tools such as the Rational Appscan
suite which can be included in your continuous integration (CI) strategy. Many organizations will centralize their security testing efforts.
Exploratory testing. The fundamental goal of exploratory testing is to discover where the solution breaks, as opposed to confirmatory testing which focuses on showing that the solution conforms to the requirements (this is the type of testing the development team typically focuses on). Exploratory testing is also a skill, a good one which everyone should strive to pick up, but exploratory testers are often few in number in many organizations. So, to leverage their skills effectively you may want to have some of them on the independent test team while they mentor others while doing so.
Non-functional testing. Non-functional requirements have a tendency to fall through the cracks on some development teams. Knowing this the independent test team will often "test to the risk" and focus on non-functional issues.
And much more. The above points are just exemplars, not an exact list. Please follow some of the links above for greater detail.
I'd like to leave you with several important thoughts:
The developers still do the majority of the testing. Just because there's an independent test team it doesn't imply that they are the ones doing all the testing. In fact, nothing could be further from the truth. They should be doing the minority of the testing effort, albeit the more difficult forms of it.
An independent test team will support multiple dev teams. For example, a test team of 5-6 people could support several development teams totalling 70 to 80 people. I typically look for a 15:1 or 20:1 ratio of developers to independent testers, hopefully even higher than that.
- You need to consider better tooling. Although the development team will still be using common agile testing tools such as the xUnit and FIT frameworks the independent test team (ITT) will need more sophisticated tooling. First, the ITT will need to be able to report defects back to the team easily. When the development team is using a Jazz-based tool such as Rational Team Concert (RTC) then this can easily be done using either RTC (the web interface may be sufficient) or another Jazz-enabled product such as Rational Quality Manager (RQM). Second, the ITT will likely need more sophisticated testing tools, such as Rational Appscan for static and dynamic security testing and Rational Performance Tester (RPT) for performance testing (just two of several software quality management tools you should consider).
Independent testing is economical. Although I listed several tools in my previous point (hey, I do work for a vendor after all) an "unfortunate" implication of my advice (unfortunate for IBM at least) is that you can reduce the number of licenses that you require and still get this critical testing done by centralizing their use.
It may be a bit more complicated in regulatory environments. In a strict regulatory environment the independent test team may need to repeat, or at least validate, the testing efforts of the development team. In regulatory environments my fundamental advice is always this -- Have practical people, including yourself, read and interpret the regulations. If you leave it to the bureaucrats you'll get a bureaucratic solution.
This is an important scaling technique. Parallel independent testing, when done in an agile manner, is an important technique which you should consider when scaling agile strategies to meet the uniques needs of the situation that you find yourself in.
Modified by ScottAmbler
An imporant step in scaling your agile strategy is to adopt a Disciplined Agile Delivery (DAD)
approach instead of one which is just focused on agile construction. One aspect of adopting a DAD approach it to mature your focus from just producing software to instead providing a solution which meets the needs of its stakeholders within the appropriate economic, cultural, and technical constraints. The fundamental observation is that as IT professionals we do far more than just develop software. Yes, this is clearly important, but in addressing the needs of our stakeholders we will often:
Provide new or upgraded hardware
Change the business/operational processes which stakeholders follow
Change the organizational structure in which our stakeholders work
Update supporting documentation
And yes, develop high-quality software
Although delivery of high-quality, working software is important it is even more important that we deliver high-quality working solutions to our stakeholders. Minimally IT professionals should have the skills and desire to produce good software, but what they really need are the skills and desire to provide good solutions. We need strong technical skills, but we also need strong "soft skills" such as user interface design and process design to name just two.
The shift to a solution-oriented focus from a software-oriented focus requires your agile teams to address some of the software-oriented prejudices which crept into the Agile Manifesto
. The people who wrote the manifesto (which I fully endorse) were for the most part software developers, consultants, and in many cases both. It is little wonder that this group would allow a bias towards software development creep into the language of their manifesto.
I have a young daughter and she's at the age where she wants to dress herself. The problem is that if we pick a single outfit and try to get her to wear it she refuses (I've lost count of the times I've heard "I don't want that"). At the other extreme if we let her pick her own outfit from the closet she'll be there for hours trying everything on. As experienced parents advise what we need to do is present her with two or three choices and ask her to pick what she wants.
So how does this relate to software development? Once again, let's look at extremes. First, consider Scrum's approach of prescribing a single way of doing things. For example, Scrum prescribes that you hold a daily meeting, called a Scrum, where everyone stands up and answers the same 3 questions. Scrum also prescribes a single change management strategy where you have a stack of requirements prioritized by business value. Scrum prescribes three roles - ScrumMaster, Product Owner, and Team Member - as well as other things. Don't get me wrong, these strategies are all great in certain circumstances but not for all. Prescribing one way of doing things is an extreme, so perhaps we shouldn't be surprised when people refuse to do it that way or struggle to make it work given the situation that they face.
At the other extreme consider RUP's approach where it presents repository of techniques from which to select the ones appropriate for you. The problem is that now we have an overwhelming way of doing things from which to choose, all of them good options in certain situations. So why are we surprised when teams struggle to identify a coherent tailoring of RUP?
Now let's consider the middle ground. The Disciplined Agile Delivery (DAD) process decision framework takes a goals-driven approach. So, instead of saying "hold a daily stand up meeting and answer these three questions" it says to regularly coordinate within the team and there are several ways of doing so (hold a Scrum meeting, hold a Kanban-style meeting, and so on). Yes, DAD does provide a large number of techniques to choose from (as does the agile community in general) but it also provides a straightforward way to choose between them. DAD does this by describing the advantages and disadvantages of each technique and suggests when, and when not, to use each approach. When people are presented with viable options, and the trade-offs associated with each, it's much more likely that they'll choose an approach that is better suited for their situation.
Scrum's single prescribed strategy works well only when that strategy is appropriate for the situation at hand. Similarly, telling my daughter exactly what to wear works well only when she's in the mood to wear that outfit. RUP's cafeteria approach to software process works well when you have the expertise, and time, to choose what's best for you. Similarly, asking my daughter to pick out her outfit from all the choices in her closet only works well when I've got a lot of time to wait for her. In both situations a better strategy is to present options, describe the trade offs, and then let people pick what's right for them given the context of the situation that they face. This is exactly what the DAD framework promotes.
I believe the goals-based approach of Disciplined Agile Delivery (DAD) represents an important step forward in the software process realm. It's time to recognize the extremes for what they are and move to a more viable middle ground.
I recently recorded an audio podcast
about Collaborative Development and Operations (DevOps) and how it relates to Disciplined Agile Delivery (DAD)
. The podcast is 17 minutes long and covers a range of topics including:
- What are the challenges typically faced by Disciplined Agile Development teams as they begin to transition their working solutions into production?
- How best could this gap between Development and Operations be closed so that they worked collaboratively rather than in silos?
- If this DevOps gap was decreased or even closed, what would the measurable value be to Agile projects and their business stakeholders?
On a related note, IBM's Collaborative Development and Operations
landing page has some great resources if you're interested in how to implement.
Modified by ScottAmbler
For several years now I've written various articles and newsletters on the topics of estimating and funding strategies for software development projects, and in particular for agile software development projects. Whenever I talk to people about agile software development, or coach them in how to succeed at it, some of the very first questions that I'll be asked, particularly by anyone in a management role, is how to fund agile software development projects. Apparently a lot of people think that you can only apply agile strategies on small, straightforward projects where it makes sense to do a time and materials (T&M) approach. In fact you can apply agile strategies in a much greater range of situations, as the various surveys
that myself and others are showing time and again. My goal with this blog posting is to summarize the various strategies for, and issues surrounding, the funding of agile software development projects.
There are three basic strategies for funding projects, although several variations
clearly exist. These strategies are:
- "Fixed price". At the beginning of the project develop, and then commit to, an initial estimate based on your up-front requirements and architecture modeling efforts. Hopefully this estimate is given as a range, studies have shown that up-front estimating techniques such as COCOMO II or function points are accurate within +/- 30% most of the time although my July 2009 State of the IT Union survey found that on average organizations are shooting for +/- 11% (their actuals come in at +/- 19% on average, but only after doing things such as dropping scope, changing the estimate, or changing the schedule). Fixed-price funding strategies are very risky in practice because they promote poor behavior on the part of development teams to overcome the risks foisted upon them as the result of this poor business decision. It is possible to do agile on a fixed budget but I really wouldn't recommend it (nor would I recommend it for traditional projects). If you're forced to take a fixed-price approach, and many teams are because the business hopes to reduce their financial risk via this approach not realizing that it actually increases their risk, then adopt strategies that reduce the risk.
- Stage gate. Estimate and then fund the project for given periods of time. For example, fund the project for a 3-month period then evaluate it's viability, providing funding for another period of time only to the extent that it makes sense. Note that stages don't have to be based on specific time periods, they could instead be based on goals such as to intiate the project, prove the architecture with working code, or to build a portion of the system. Disciplined agile methods such as Open Unified Process have built in stage-gate decision points which enable this sort of strategy. When the estimation technique is pragmatic, the best approaches are to have either the team itself provide an estimate for the next stage or to have an expert provide a good gut feel estimate (or better yet have the expert work with the team to develop the estimate). Complex approaches such as COCOMO II or SLIM are often little more than a process facade covering up the fact that software estimating is more of an art or a science, and prove to be costly and time consuming in practice.
- Time and materials (T&M). With this approach you pay as you go, requiring your management team to actually govern the project effectively. Many organizations believe a T&M strategy to be very risky, which it is when your IT governance strategy isn't very effective. An interesting variation, particularly in a situation where a service provider is doing the development, is an approach where a low rate is paid for their time which covers their basic costs, the cost of materials is paid out directly, and delivery bonuses are paid for working software. This spreads the risk between the customer/stakeholder and the service provider. The service provider has their costs covered but won't make a profit unless they consistently deliver quality software.
The point is that there are several strategies for funding agile software development projects, just like there are several strategies for funding traditional software development projects. My experience is that fixed-price funding strategies are incredibly poor practice which increases the risk of your software development projects dramatically. I recognize how hard it can be to change this desire on the part of our business stakeholders, but have also had success changing their minds. If you choose to perservere, which is a difficult decision to make, you can help your organization's decision makers to adopt more effective strategies. Like you they want to improve the effectiveness of your IT efforts.Further reading: (In recommended order)
- Something's Gotta Give: Argues for a flexibly approach to funding, schedule, and/or scope.
- Agile on a Fixed Budget: Describes in detail how to take a fixed-price approach on agile projects.
- The Dire Consequences of Fixed-Price IT Projects: Describes in detail the questionable behavior exhibited by IT teams when forced to take a fixed-price approach.
- Is Fixed-Price Software Development Unethical?: Questions the entire concept of fixed-price IT projects, overviewing some of the overwhelming evidence against this really poor practice.
- Reducing the Risk of Fixed-Price Projects: Describes viable strategies for addressing some of the problems resulting from the decision of fixed-price projects.
- Strategies for Funding Software Development Projects: Describes several variations on the strategies described above.
- Lies, Great Lies, and Software Development Project Plans: Summarizes some results from the July 2009 State of the IT Union survey which explored issues related to project funding (among many).
Modified by ScottAmbler
In 2009 I wrote a white paper entitled The Agile Scaling Model (ASM): Adapting Agile Methods for Complex Environments for IBM Rational. Apparently it's been taken down, which I think is unfortunate as it contains some interesting ideas that your organization may be able to benefit from.
The original white paper addresses several key issues:
It provides and explains a definition for disciplined agile delivery. A more up to date discussion of DAD can be found on the Disciplined Agile Delivery site.
It describes criteria to determine is a team is agile. I've explored this issue via several surveys over the years since then. See the January 2013 How Agile Are You? results.
It describes the ASM, which distinguishes between core agile development techniques, disciplined agile delivery strategies, and agility at scale. The ASM was superceded in early 2013 by the Software Development Context Framework (SDCF). Perhaps this is why the ASM paper was taken down??
It overviews the eight scaling factors which a delivery team may face, scaling factors which motivate changes in the process that you will follow and the tools that you will adopt. The SDCF provides my recent thoughts regarding scaling factors. I have also run various IT Surveys over the years exploring how well organizations fare at scaling agile.
It describes the implications of the ASM. My blog posting Scaling Agile: Start with a Disciplined Foundation covers this very well.
It argues that you should strive to be as agile as you need to be, and that will be driven by the situation that you face.