Cloud Models and Platforms

A Working defination of cloud computing

• Cloud computing is a model for enabling convenient, on-demand network
  access to a shared pool of configurable computing resources (e.g., networks,servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

Objectives of Cloud Computing

⚫ Elasticity: Ability to scale virtual machines resources up or down
⚫ On-demand usage: Ability to add or delete computing power (CPU,
memory), and storage according to demand
⚫ Pay-per-use: Pay only for what you use
⚫ Multitenancy: Ability to have multiple customers access their servers in the
data center in an isolated manner

3 Cloud Service Models

⚫ Cloud Software as a Service (SaaS)
The capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure and accessible from various client devices through a thin client interface such as a Web browser (e.g., web-based email). The consumer does not manage or control the underlying cloud infrastructure, network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.

⚫ Cloud Platform as a Service (PaaS)
The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created applications using programming languages and tools supported by the provider (e.g., Java, Python, .Net). The consumer does not manage or control the underlying cloud infrastructure, network, servers, operating systems, or storage, but the consumer has control over the deployed applications and possibly application hosting environment
configurations.

⚫ Cloud Infrastructure as a Service (IaaS)
The capability provided to the consumer is to rent processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems,
storage, deployed applications, and possibly select networking components (e.g., firewalls, load balancers).

⚫To be considered “cloud” they must be deployed on top of cloud
infrastructure that has the key characteristics

3 Cloud Deployment Models

⚫ Private cloud
The cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on premise or off premise.

⚫ Public cloud
Mega-scale cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.

⚫ Hybrid cloud
The cloud infrastructure is a composition of two or more clouds (private or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability

Cloud Security Challenges

⚫ Trusting vendor’s security model
⚫ Multi-tenancy (serves multiple tenants)
⚫ Data ownership issues
⚫ QoS guarantees
⚫ Attraction to hackers (high-value target)
⚫ Security of virtual OSs in the cloud
⚫ Obtaining support from cloud vendor for security related investigations

⚫ Indirect administrator accountability
⚫ Proprietary cloud vendor implementations can’t be examined
⚫ Loss of physical control
⚫ Possibility for massive outages

Cloud Security Advantages

⚫ Shifting public data to a external cloud reduces the exposure of the
internal sensitive data
⚫ Dedicated Security Team
⚫ Greater Investment in Security Infrastructure
⚫ Cloud homogeneity makes security auditing/testing simpler
⚫ Clouds enable automated security management and real-time
detection of system tampering
⚫ Rapid Re-Constitution of Services
⚫ Redundancy / Disaster Recovery