Cloud Computing: Deployment & Service Models
Understanding Where and How Cloud Services are Delivered
This lecture explores the foundational models that define how cloud environments are built and what kinds of services they offer.
Today's Topics
Part 1: Deployment Models
Where the cloud infrastructure resides (Private, Public, Community, Hybrid).
Part 2: Service Models
What kind of service is offered (IaaS, PaaS, SaaS, AaaS).
Think of it as the difference between where you eat (at home, a restaurant, a potluck) and how your food is prepared (raw ingredients, a meal kit, a fully cooked meal).
Part 1: Cloud Deployment Models
A cloud deployment model defines the specific type of cloud environment based on ownership, scale, and access, as well as the cloud's nature and purpose.
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Private Cloud
A Private Cloud consists of cloud computing resources used exclusively by a single business or organization. It can be physically located at the company’s on-site data center or hosted by a third-party service provider.
Imagine owning a private kitchen. You have complete control over the appliances, ingredients, and recipes. No one else can use it.
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Advantages
Enhanced Security & Privacy: Greater control over data.
Customization: Tailor the environment to specific needs.
Compliance: Easier to meet strict regulatory requirements.
Disadvantages
Higher Costs: Significant capital expenditure for hardware and maintenance.
Limited Scalability: Scaling requires purchasing and provisioning new hardware.
Management Overhead: Requires a skilled IT team to operate.
Public Cloud: The Utility Model
A Public Cloud is owned and operated by a third-party cloud service provider (e.g., Amazon Web Services, Microsoft Azure, Google Cloud). The resources, such as servers and storage, are delivered over the public internet and shared by multiple organizations (multi-tenant).
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This is like a large public restaurant. You don't own the kitchen or hire the staff, you just pay for the meal you want. The restaurant serves many customers simultaneously.
Advantages
Lower Costs: No hardware to buy; pay-as-you-go model.
High Scalability & Elasticity: Virtually unlimited resources on demand.
Reduced Maintenance: The provider handles infrastructure management.
Disadvantages
Security & Privacy Concerns: Data resides on shared infrastructure.
Less Control: Limited customization options.
Vendor Lock-in: Can be difficult to migrate to another provider.
Community Cloud: A Shared Endeavor
Community Cloud involves a cloud infrastructure that is provisioned for exclusive use by a specific community of consumers from organizations that have shared concerns (e.g., mission, security requirements, policy, and compliance considerations).
Think of a community garden shared by residents of an apartment building. They all share the space, tools, and costs because they have a common interest in growing fresh vegetables.
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Advantages
Cost Sharing: Costs are distributed among fewer users than a public cloud.
Collaborative: Facilitates joint projects and data sharing.
Specific Compliance: Can be built to meet the specific needs of the community.
Disadvantages
Higher Cost than Public: Not as economical as a large-scale public cloud.
Shared Resources: Still involves multi-tenancy within the community.
Governance Challenges: Requires collaboration and joint agreements.
Hybrid Cloud: The Best of Both Worlds
Hybrid Cloud combines a private cloud with one or more public cloud services, with proprietary software enabling communication between each distinct service. This allows workloads to move between private and public clouds as computing needs and costs change.
This is like having a kitchen at home (private cloud) for everyday meals, but ordering from a restaurant (public cloud) for large parties or special occasions.
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Advantages
Flexibility: Use the best environment for each workload.
Scalability: Leverage the public cloud for on-demand scaling ('cloud bursting').
Security: Keep sensitive data in the private cloud while using public cloud for other tasks.
Disadvantages
Complexity: More difficult to manage and secure.
Integration Challenges: Ensuring seamless communication between clouds can be hard.
Network Dependencies: Relies on a stable, secure connection between environments.
Deployment Model Comparison
Model | Ownership | Tenancy | Best For |
|---|---|---|---|
Private | Single Organization | Single-Tenant | Control & Security |
Public | Cloud Provider | Multi-Tenant | Scalability & Cost-Effectiveness |
Community | Group of Orgs | Multi-Tenant (within group) | Collaboration & Shared Cost |
Hybrid | Org & Provider | Mixed | Flexibility & Balance |
Part 2: Cloud Service Models
Cloud service models describe the level of service and management provided by the cloud vendor. They define the division of responsibility between the provider and the consumer.
Infrastructure as a Service (IaaS)
IaaS provides virtualized computing resources over the internet. It's the most basic category of cloud computing services. You rent IT infrastructure—servers and virtual machines (VMs), storage, networks, operating systems—from a cloud provider on a pay-as-you-go basis.
You get the fundamental building blocks. It's like renting a plot of land with utility connections. You decide what kind of house to build, how to build it, and what to put inside.
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Platform as a Service (PaaS)
PaaS provides a complete development and deployment environment in the cloud, with resources that enable you to deliver everything from simple cloud-based apps to sophisticated, cloud-enabled enterprise applications.
You get a workshop with all the tools ready to go. It's like renting a pre-built house frame and foundation. You don't worry about construction, just the interior design and furnishing.
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Software as a Service (SaaS)
SaaS allows users to connect to and use cloud-based apps over the Internet. Common examples are email, calendaring, and office tools (such as Microsoft Office 365 or Google Workspace). You subscribe to the software rather than buying it.
You get a finished, ready-to-use product. It's like renting a fully furnished and serviced apartment. You just move in and use it; all maintenance is handled for you.
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Analytics as a Service (AaaS)
AaaS is a specialized form of SaaS that provides analytics software and operations through web-delivered technologies. It allows organizations to use powerful data analysis tools without the complexity of building and maintaining their own analytics infrastructure.
Instead of just renting an apartment (SaaS), you are hiring a professional interior designer who brings their own tools and expertise to furnish and decorate it for you based on your preferences.
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Key Takeaways
Deployment Models (Where): Dictate the location and ownership of the cloud. Your choice depends on your needs for control, scalability, and cost.
Service Models (What): Define the level of abstraction. Your choice depends on how much you want to manage yourself versus how much you want the provider to handle.
These models are not mutually exclusive. For example, you can run a SaaS application on a Private Cloud, or use IaaS from a Public Cloud provider to build a platform for a Hybrid Cloud environment.
Questions?