5. Virtualization as the ‘Operating
System’
Hardware
Hypervisor
Virtual Operating Environment
Guest Operating
System
Application
Programs
Guest Operating
System
Application
Programs
Guest Operating
System
Application
Programs
In this type of virtualization the hypervisor
is the separating layer between guest
operating systems and the hardware.
6. Virtualization with a Host Operating
System
In this type of virtualization a host operating system is
used as the first tier of access control.
Host Operating System
Hypervisor
Virtualization Layer
Guest Operating
System
Application
Programs
Guest Operating
System
Application
Programs
Guest Operating
System
Application
Programs
Hardware
8. Multi-tenancy Architecture
• Rationale:
• ‘a large number of users, basically multi-tenants, makes the
cloud platform most efficient in terms of usability of the
application and ‘Do More With Less Resources’. (Rajan,
2011)
• Key element (&issue) is Security
• Security needs to be ensured at all levels of the
infrastructure
• Examples:
• Salesforce.com: a SaaS-based CRM application for various
businesses using common framework and multi-tenancy
model
• Microsoft Dynamics CRM Online offering
• Multi-tenancy IaaS/PaaS offerings from Amazon or IBM or
Microsoft Azure
9. 1.3.2 Service Oriented Architectures
• Service-Oriented Architecture (SOA)
• an architectural style that supports service orientation.
• Service orientation
• a way of thinking in terms of services and service-based
development and the outcomes of services.
• Service
• a logical representation of a repeatable business activity
that has a specified outcome (e.g., check customer credit,
provide weather data, consolidate drilling reports);
• self-contained;
• May be composed of other services;
• a “black box” to consumers of the service.
Source: Cloud working group, The Open Group.
10. Cloud and SOA
• Question: (Paul Krill)
• ‘Can we build a datacenter infrastructure on SOA
principles?’
• Answer: (Gerry Cuomo)
• ‘Yes, and that's the cloud, so it's a service-oriented
infrastructure,… It's taking that architectural principle of
SOA and applying it to an infrastructure.’
‘The cloud-SOA connection’ (Krill, 2009)
• A service-oriented architecture is basically a collection
of services that communicate with each other.
• Connecting these services in many cases involves Web
services using XML
No Cloud without SOA!
11. Service Oriented Architecture
Criteria
• In order to implement SOA, the architecture must meet the
following criteria:
• Services that are able to communicate with each other
• A well understood interface
• A message-oriented communication process
