1.What is Cloud Computing?
- Consider a ‘Phone Network’. When we want to place a call, we don’t create our own phone network, the infrastructure already exists, we utilize it based on our needs. We subscribe to the available phone services at minimal fees (say like leasing or renting) without having to buy the whole structure and set-it up. There, you just understood in simple terms the definition of cloud computing.
- Definition by National Institute of Standards and Technology (NIST): 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.
2. Main Concepts of Cloud Computing
- Abstraction: The process of hiding specific details to simplify or generalize something. Think of storage (the server it resides in isn’t pertinent, we just want to access the data stored in it whenever required)
- Virtualization: Process in which software manages hardware resources of physical hosts so resources can be used more efficiently by multiple virtualized guest systems (Virtual Machine)
3. Cloud Layers
- Infrastructure Cloud: Abstracts applications from servers and servers from storage (basic physical layer of storage and server). It comprises the physical components that run applications and stores data. Virtual abstraction is employed to manage servers and storage as logical rather than individual physical entities.
- Content Cloud: Abstracts data from applications (needs access to data, maybe device also). It implements metadata and indexing services over the infrastructure cloud to provide abstracted data management for all content. It aims to abstract data from the applications so that different applications can access the same data and can be changed without worrying about data structure or type.
- Information Cloud: Abstracts access from clients to data. The best example is the Internet, abstracts all the data and user can access data stored in any database.
4. Cloud Characteristics
- Elasticity: The provision and de-provision of resources and services as required(flexibility)
- On-demand: Available all the time and accessible from any given network connectivity.
- Provider-pooled computing resources: Operates entirely from cloud based services (reduces dependency on hardware)
- Metered service usage: Subscription fee depends on user billing model.
- Broad network access: Can access from any type of device (mobile, desktop, etc.)
5. Cloud Implementation Models
- Private Cloud Deployment Model: Owned and maintained by a single private organization, can be controlled from a single and centralized location. Enables an organization to centralize access to all the IT resources, administration can be carried out by internal or outsourced parties. Enhanced security (security/trust boundary is within the organization), cost is more as lot of equipment required.
- Public Cloud Deployment Model: Services and infrastructure are provided to various clients, owned by a third-party cloud provider. Hardware, software, licensing, and maintenance is taken care by third party. Host Software as a Service application. E.g., google storage
- Community Cloud Deployment Model: Like public cloud but access is limited to specific community members. Cost is lesser when compared to private cloud. E.g., Government department requiring access to data concerning local population.
- Hybrid Cloud Deployment Model: Mix of any deployment models, can be used to handle cloud bursting. Helps in scaling up IT infrastructure rapidly. There are concerns with the split management responsibility and complexity of implementing different deployment models.
6. Business Cloud Models
- Cloud-Based: The model is completely reliant and based on cloud computing environment, applications are entirely hosted on the cloud. End users access the application or data with credentials (username and password)
- Cloud-Enabled: The model uses some components of cloud computing, portion of business functionality is reliant on cloud-based applications, but not entirely dependent on cloud services.
-Sanjana