Service Configuration: A Semantic Model

Service ConfigurationA Semantic Model

Demand for Reliability of IT

Providing and defending the reliability of IT systems is the biggest driver of efforts to manage the way components interact with each other to generate outcomes that are specific enough and good enough to offer as a service.

Choosing the components and their arrangements calls on both engineering (for viable functionality) and architecture (for logical feasibility).

However, the necessary choices to be made for reliability are actually about several factors that are “elements” of the service.

Components are only one kind of factor. Relationships, requirements, circumstances, and other issues are other types of factors that are also elements.

To manage reliability – by providing, sustaining or restoring it – the “necessary” data is data about the elements.

Expectations of the Demand

We normally talk about the elements in nearly narrative ways that describe the service.

The semantics of the narration itself tell us how we normally recognize and expect when something “should” work.

In fact, that recognition “intuitively” tells us why we think our subject of interest – a service – should work.

Illustrating that recognition tells us how we can represent the service for manageability.

Naturally, management will rely on the representation to identify what it can influence, and how it can exert the influence in a practical way.

The practicalities are in providing, maintaining or restoring the service. All of those efforts address the organization of the service elements.

How elements of a service are logically organized in the serviceModel (noun) - a simplified representation of a complex system or entity, especially one designed to facilitate calculations and predictions.

To derive the organization of a service, we first ask what is meaningful and why, then we arrange things to show how the meanings are related, demonstrated and used.

A demand-based story

Narrative (of meaning)

• Make sure the needed service is available and used when and how it is appropriate

• Choose an effective type of service

• Produce the service with the appropriate resources and form

• Utilize an appropriate resource for the service

Elements

• Assurance

• Requirements

• Assignments

• Components

©2015 Malcolm Ryder / Archestra Research

Service TypeFunctionality– Capability- Tolerance

Service ResourceActivity – Suitability – Responsibility

Service Item DesignConfiguration – Effects – Events

Service Operation ModelContinuity – Policy – Exposure

Service Item

DEMAND

component assignment requirement assurance

Factors within the elements…


Example

An example from real life can be used to show this idea.

In the example, we describe a key part of a system, describe how that part provides a service, and describe the service – relying on key factors that show how things are expected to work.

All together, those descriptions align (model) the factors in a way that would be maintained to ensure that desired results are most probable.

Therefore, if undesirable results arose instead, those results might be evidence that something is out of alignment.

The example is a baseball game in which a coach (the manager) decides to use a certain type of pitcher in a game situation for a specified outcome.

“I’ve got a left-hander who can throw only fastballs and sliders for no more than four innings.”

Pitcher X

PITCHING

DEFENSEService

Sub-service

Sub-sub-service

RESOURCE SPECIFICATION.

An enablement of a serviceis intentional or not,

permanent or not, and risky or not. Management both

determines and aims for the positives.

The Manager makes a decision about when and

why to deploy this resource.

The deployment enables a service.

Fastballs, sliders

I’ve got a left-hander who can throw only fastballs and sliders for about20 pitches per inning for no more than four innings.

Pitcher X

Certain basic activity is available from the pitcher in question.


Fastballs, sliders

Strikeouts, grounders

(Suitable For)


Application: what should I use him for?

Pitcher X

The available action will be employed for a certain effect.


Fastballs, sliders

While leading/tied Strikeouts, grounders


Operation: when should I use him?

Pitcher X

This decision is the deployment bet… Fastballs and sliders will be used to preserve the tie or the lead – so the tie/lead will then be dependent on them


Fastballs, sliders


(Suitable For)

The Gametime (Service) AssignmentActivity – Suitability – Responsibility

Pitcher X

This summarizes the planned use of the pitcher.


Suitable For(tolerances) (capabilities)

(functionalities)

Pitcher X

The Service RequirementFunctionality– Capability- Tolerance

This is the decision model used, that selects the right pitcher as a resource to serve a current need.


Fastballs, sliders



Limits on the Resource Role

Pitcher X

Versus lefty hitters

These circumstances shape the role that the pitcher will play.


Fastballs, sliders


Suitable For

Versus lefty hitters

(tolerances) (capabilities)

(functionalities)

Pitcher X

The Service SpecificationResource + Role + Assignment

This scenario is the “best case” one in which the pitcher is expected to succeed.


Service item as a resource in a role for an operationThe pitcher is the item committed to the service needed by the manager.

Configuration For

Certain events Effects including

Service Design of Item

Service Item


tolerances capabilities

functionalities


Service Item


Suitable For(tolerances) (capabilities)

(functionalities)

Service Resource ModelActivity – Suitability – Responsibility

Service Item


Configuration For

Certain events

Suitability For(tolerances) (capabilities)

(functionalities)

Service Item

Effects including

Service Role ModelConfiguration – Effects – Events


Configuration For

Certain events

Suitability For

Policy/requirement

(tolerances) (capabilities)

(functionalities)


Service Item

Effects including






Service Item

DEMAND


Factors within the elements…


Comparison: Generic & Example

Service Item Pitcher X

An item comes with pre-existing behaviors that can besubscribed to a given state of need and purpose. The

behaviors come from how the item is built to act.


The required type of service calls for only certain characteristics of an item. Those characteristics will qualify the item for active service duty. The

qualifications include functionality, capability and tolerances.


An item is not a resource merely because it has some potential;an item is a resource because it has an assignment.

The qualifications for being the assignment’s resource include designated activity, suitability and responsibility.


The resource performs the assignment as a role in the prevailing circumstances.The role requires that the resource’s characteristics will be effective in the circumstances.

The circumstances may be pre-defined as constraints and thresholds of operation.


The constraints and thresholds of operation around performing any roleinclude continuity, policy and exposure demands or limits. Those are

variables that are themselves under some degree (more or less) of control.

When an experienced baseball manager makes a lineup decision, and he wants to “get service” from a player, he already has

the entire picture (example at right) of related issues in his head.


Configuration DiagnosticsThe configuration of the service must be understood in order to determine what to do about the service usage results.

Service TypeFunctionality – Capability – Tolerance




Service Item

DEMAND


Each higher-level element is supported by one or more types, and/or instances, of the element below it. Each factor in an element is both a success factor and a risk factor. All factors are continuously observable. Any factor may go through a modification independently of other factors. A recognizable defect, omission or error may be found at any factor within any element.


Service Configuration: A Semantic Model

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