Cloud is about achieving a steady state where dynamism is the norm but actions and reactions are in perfect balance. It’s called “dynamic equilibrium” and you’ll need to pass Cloud Chemistry 101 to get there.

 

image When you were a kid you might have had a goldfish. It lived in a bowl of water and you fed it and if you were lucky it lived for quite a while. You certainly didn’t concern yourself with things like water quality (unless the water started turning green, of course) or pH or alkalinity or gas exchange rates. Circulation and total dissolved solids (TDS) were not in your vocabulary and understanding the nitrogen cycle was something you might one day explore in high school biology or chemistry – but it wasn’t a concept you took home and applied to your goldfish bowl.

Even twenty years ago when marine reef keeping started to become popular these concepts were not something that were generally applied let alone understood. But like technology, our understanding of how all these factors interact on a daily basis to create a thriving ecosystem have come a long way. Today, it’s better understood how the dynamism of an aquarium impacts overall water quality (and thus the survivability of its inhabitants) but more importantly we’re learning quickly how to manage that dynamism such that we can achieve a state of dynamic equilibrium; a state in which a stable environment is created despite its underlying rapid rate of change.

Sound like the data center of today? Like cloud computing ? Like application delivery in general? It should, because just as the industry of reef keeping is advancing quickly such that we are learning to architect systems that achieve dynamic equilibrium, so too are we doing the same with cloud computing and application delivery.

WATER CLOUD CHEMISTRY 

The technical definition of dynamic equilibrium is quite involved, requiring an understanding of chemistry and reactions and unfortunately for some of us a whole lot of math.

dynamic equilibrium

blockquote A dynamic equilibrium exists when a reversible reaction ceases to change its ratio of reactants/products, but substances move between the chemicals at an equal rate, meaning there is no net change. It is a particular example of a system in a steady state. In thermodynamics a closed system is in thermodynamic equilibrium when reactions occur at such rates that the composition of the mixture does not change with time. Reactions do in fact occur, sometimes vigorously, but to such an extent that changes in composition cannot be observed. [emphasis added]

-- Wikipedia, Dynamic Equilibrium

The basic principle here, however, is really quite simple: you want to create an environment, a system, in which reactions to change – regardless of frequency – are well-balanced. It’s almost Newton’s third law of motion which implies that the mutual forces of action and reaction between two bodies are equal, opposite and collinear. Newton’s law requires that action and its reaction are simultaneous; in aquariums and data centers the reaction is not necessarily simultaneous, although it is close enough to be considered applicable.

In an aquarium, as the bioload (waste production, oxygen and nutrient consumption) increases a reaction occurs that also increases the ability of the biological filtration system to manage the additional load. In some cases, such as when the rate of oxygen depletion exceeds the ability of the system to introduce oxygen to the water, additional mechanical or chemical components may be necessary to increase the overall capacity. If that’s beginning to sound like an application and cloud computing, it should.

For example, when a request for an application is received, the action is an increase in application demand. That increase in demand may evoke a reaction from the infrastructure if capacity is not available to meet that demand. In cloud computing and highly virtualized data centers, this is assumed to be the provisioning of additional capacity such that the request can be processed. Appropriately, as demand decreases so should capacity (what goes up must come down). As a result, a dynamic equilibrium is achieved; a steady state of change that makes it appear to the user that the system is stable while the reality is that the infrastructure is in a constant state of change based on the state of the data center at any given time.

COMPOSITION of an APPLICATION

Dynamic equilibrium maintains that a system is in equilibrium when reactions occur at such rates that the composition of the mixture does not change with imagetime. In a data center, the composition associated with the data center and subsequently cloud computing is the application and comprises:

● security posture

● availability (capacity)

● performance levels

● costs

As demand, device and location diversity fluctuate it is the goal of application delivery to maintain the composition. In order to maintain the security posture, it may be necessary to apply policies. To maintain availability it may be necessary to provision or modify the compute, network, and storage resources. Maintaining performance levels may require the use of rate shaping or acceleration or optimization services. And costs may be controlled by leveraging resources based not just on function but cost.

Cloud computing is about process; it’s about devops and the ability of infrastructure to collaborate and automate its reaction to changing application and data center conditions. The ability to react within context to changes in the ecosystem with the appropriate reaction such that the overall state of the application is sustained. Whether through technology or process, resource management, or policy or some combination thereof, the goal is to sustain a steady state for an application. To maintain security and performance while managing costs and capacity. No single piece of the equation can be ignored or dispensed with, because that would throw the system out of balance.

This is impossible to achieve manually. Do not be fooled into thinking that such an environment can be achieved without technology. Doing so requires pre-positioning and deployment which results in increasing waste and “bioload” that unbalances the environment by creating too much cost and capacity overhead. It is precisely the ability to automate the processes that adjust the composition of the application based on current conditions – context – that make it possible to achieve technological dynamic equilibrium. But those adjustments need to happen in the right place within the system. Filtering out toxins produced by some corals in their efforts to secure their “space” in an aquarium require that certain chemical and mechanical filtration be placed in the flow at the right place. Similarly, in a data center, the application of security and performance-related policies must occur at the right place and time in the data flow to ensure efficiency and effectiveness of those policies in reacting appropriately to changes in the ecosystem.

This is the underlying driver for Infrastructure 2.0, for a dynamic control plane comprising the entire network, storage, and application network infrastructure: report-cardthe ability to intercept, inspect, and instruct the components in such a way as to stabilize an application even as its composition is changing. 

Dynamic equilibrium is the goal of cloud computing and IT as a Service and those who spend far too many hours toying with a reef aquarium. The reef aquarist  knows they’ve achieved dynamic equilibrium when the animals and life in that environment are thriving and growing without interference. When applications are delivered securely and are always available and perform up to business and end-user satisfaction and are able to scale seamlessly - without manual interference -then we’ll know we’ve achieved dynamic equilibrium in the data center. You’ll have earned an “A+” in Cloud Chemistry 101.

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