In the previous segment, you learnt about the different cloud deployment models available in the market and how organisations choose clouds according to their requirements.
In this segment, you will understand the types of services enabled by the cloud. Let’s hear about this from our SME.
Cloud Service Models
On-demand cloud services are of mainly three types:
1. Infrastructure as a Service (IaaS): These services are a set of compute, storage and network that are virtualised by cloud providers so that users can access and configure resources according to their needs. With IaaS, a user can rent IT infrastructure.
- Common examples of IaaS are as follows:
- AWS EC2
- Google Compute Engine (GCE)
- Digital Ocean
Here are some of the advantages of Infrastructure as a Service:
- The service provider provides the infrastructure, and the user has to just install an operating system of their requirements and work on it.
- The user can modify the architecture as per their requirements since it is basic cloud infrastructure.
- The user has full control over all the computing resources.
2. Platform as a Service (PaaS): These are cloud services that provide an on-demand environment for developing and managing a software application. PaaS can be used to build, run and manage application programming interfaces (APIs).
- The following are some of the common examples of PaaS:
- Windows Azure
- OpenShift
- AWS Elastic Beanstalk.
Here are some of the advantages and disadvantages of PaaS:
Advantages:
- Prebuilt platform: PaaS provides an already built platform for users to build and run their applications.
- It is a simple model to use and deploy applications.
- Low cost: Since the platform is already built, the user needs to create only their applications. This reduces the costs related to hardware and software.
Disadvantages:
- Migration issues: Migrating the user applications from one PaaS vendor to another might raise some issues.
- Platform restrictions: The platforms provided by some vendors may have certain restrictions, for instance, the user can use only certain specified languages.
3. Software as a Service (SaaS): These are cloud services that provide the user with a complete software application over the Internet. All the infrastructure, application tools, data, etc. are located at data centres managed by the service providers.
- Some of the examples of SaaS are as follows:
- Google Apps
- Salesforce
- Dropbox.
- There are two modes of SaaS:
- Simple Multi-Tenancy: Each user has independent resources that are different from the resources of other users.
- Fine Grain Multi-Tenancy: Resources are shared by several users but the functionality of these resources remains the same.
Here are some of the advantages and disadvantages of SaaS:
Advantages:
- Ease of access: Users can access the applications on the server from anywhere using any Internet-connected device. Most types of internet-connected devices can access SaaS applications.
- Low maintenance: Users need not update an application. The application is on the server, and it is the service provider’s responsibility to maintain the application.
- Quick setup: Users do not require any hardware to install the application. The SaaS application is already present on the cloud.
Disadvantages:
- Lack of control: Users do not have control over the SaaS applications. Only the vendor has full control of SaaS applications.
- Connectivity issue: The applications can only be accessed only via the Internet. Hence, if there is no Internet, then the users cannot access the applications.
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