Cloud Computing: Architectures Applicatives & SaaS Maturity Levels

inhérents

■ Un problème sur l’un des outils peut compromettre tous les autres

■ Complexité de maintenance / mise à jour

■ Complexité de mise à l'échelle (scalability)

○ En général déployées pour construire des environnements de

développement

SRC : https://www.cartelis.com/blog/concepts-architecture-cloud/

Les modèles N-Tier

● Présentation / Caractéristiques

○ L’architecture N-tier (anglais tier : étage, niveau), ou encore appelée multi-tier,

est une architecture client-serveur dans laquelle une application est exécutée

par plusieurs composants logiciels distincts.

● Exemple :

○ Consiste à prendre une architecture single-server et à répartir ses

composantes sur différentes serveurs (virtuels/physiques) : Serveur

Apache/PHP, Serveur MySQL.

SRC : https://www.cartelis.com/blog/concepts-architecture-cloud/

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Les modèles N-Tier

Architecture

4-Tier / n-Tier

Architecture

2-Tier

Architecture

3-Tier

SRC : http://www-igm.univ-mlv.fr/~dr/XPOSE2001/perrot/Intro-Comparatif.htm

Les modèles N-Tier

Représentation minimale des couches

d’une architecture n-tiers.

Crédit Éditions O’Reilly

Exemple de la mise en application d’un

style n-tiers composé d’un grand

nombre de couches.

Crédit Éditions O’Reilly

SRC : https://web2.cegepat.qc.ca/~claudeboutet/index.php/2016/04/14/le-pattern-architectural-n-tiers/

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Pour aller plus loin

Architecture Monolithique

Architecture à microservices

TABLE DES MATIÈRES

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Architectures Applicatives

Niveau de maturité SaaS

Version 1.0

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SaaS Maturity Model

Level I: Ad Hoc/Custom

Level II: Configurable

Level III : Configurable,

Multi-Tenant-Efficient

t

n

a

n

e

T

e

l

g

n

S

i

Level IV: Scalable, Configurable,

Multi-Tenant-Efficient

t

n

a

n

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T

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t

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M

Level I: Ad Hoc/Custom

At this level, each client has its own customized version of the hosted

application and runs its own application on the server of the host.

It's a pattern similar to that offered by ASP (Application Service Provider).

Transition from a traditional application to a level 1 SaaS application requires

minimal effort.

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Level II: Configurable

In this case, each vendor hosts a separate application instance for each client,

but all instances use the same code, and vendor provides detailed

configuration options to offer a different look and behavior of the application

for each client.

Instances remain completely isolated from one another.

Transition to this level requires more effort to change the architecture, if the

application was designed for individual customization and it does not use

configuration metadata.

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Level III : Configurable, Multi-Tenant-Efficient

This is the level of maturity for which the vendor runs a single instance

application using configurable data to offer a different look and operation for

each client.

Authorization and security policy ensures that every client data is kept secure,

separate from those of other tenants.

Although the computing resources are used more efficiently, this model has a

low scalability.

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Level IV: Scalable, Configurable,

Multi-Tenant-Efficient

Vendor hosts multiple tenants on a farm of identical instances, each client data

are stored separately, configurable metadata providing each a unique

application.

The system is scalable and increasing the number of clients does not require

changes in application architecture

Pour aller plus loin

Extra info on SaaS Maturity

https://blog.aspiresys.com/digital/cloud/understanding-the-saas-maturity-models/

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