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CLOUD COMPUTING #2 (SaaS (Characteristics (Most commonly used option for…
CLOUD COMPUTING #2
Service Models
- Software-as-a-Service [SaaS]: ready-to-use software over the network e.g SalesForce, MailChimp, DropBox
- Platform-as-a-Service [PaaS]: deploys user's own software e.g Microsoft Azure, Google App Engine, CloudBees
- Infrastructure-as-a-Service [IaaS]: offers fundamental computer resources such as computation, power, storage etc e.g Rackspace, Amazon Web Services
SaaS
- Uses the Internet to deliver applications, which are managed by a third-party vendor, to its users
- Software consumed over the web, such as a web browser [e.g web-based email] or a program interface
- Office SaaS: Microsoft Office, Google Docs etc
- Business SaaS: HR, CRM, ERP such as Salesforce
Characteristics
- Most commonly used option for businesses in the cloud market
- Accessible from any device
- No fixed costs, sometimes even free
- Continually updated [incrementally]
- Vendors manage all technical issues: results in streamlined maintenance
- Mostly run directly through web browser so doesn't require any downloads/installations on the client side
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- Dependent on a fast and reliable internet connection
- Applications run + data stored in the cloud
- Limited to vendor-determined applications: minimal customisation opportunities
- Data security: large volumes of data may have to be exchanged to the backend centres of SaaS apps to perform the necessary software functionality - security could be compromised
PaaS
- Provides cloud components to certain software while being used mainly for applications
- Delivers a framework for developers that they can build upon + use to create customised applications
- Offers the running/compiling environment w different types of tools such as programming languages, libraries + interfaces
- The PaaS/SaaS consumer doesn't manage or control the underlying cloud infrastructure, but has control over the deployed applications + configuration settings for the application-hosting environment
Characteristics
- Technical components stored in vendor's cloud
- Provides a variety of services to assist w the development, testing + deployment of apps
- No need to develop fundamental components
- Rapid development is possible
- Significant reduction in the amount of coding needed
- Vendor lock-in problem: business + technical requirements that drive decisions for a specific PaaS solution might not apply in the future; if the vendor hasn't provisioned convenient migration policies, it may not be possible to switch to alternative PaaS policies
- Compatibility problem between different platforms
- Possible security risk: data stored in third-party vendor-controlled servers may mean security options are limited
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IaaS
- A cloud provider hosts the infrastructure components traditionally present in an on-premises data centre, including servers, storage + networking hardware
- Offers the hardware environment of the whole architecture
- Involves a vendor offering computer hardware in the cloud on which their customers can store data + develop/run whatever applications they please
- Therefore, IaaS potentially allows companies to move their existing programs + data from their current servers onto the cloud + therefore to close down their own data centres/servers
Characteristics
- Often easier, faster + more cost-efficient to operate a workload without having to buy, manage + support the underlying infrastructure
- Good for workloads that are temporary, experimental or change unexpectedly
- IaaS customers usually pay on a per-use basis, typically by the hour/wk/month - this eliminates the capital expense of using in-house hardware/software
- However, cloud billing is broken down to reflect the precise usage of services, + it's common for companies to find costs higher than expected: has to be carefully monitored
- Server resilience: can be an issue if the IaaS provider experiences any form of downtime, as workloads will be affected