Cloud Computing Overview & Cloud-Native Technologies

1. Introduction to Cloud Computing

Cloud computing provides resources like servers, storage, networking, and software over a network, allowing users to access them anytime, anywhere, as needed.

• Data migration is often required when moving existing systems to the cloud.

---

1.1 Virtualization vs Cloud

Virtualization	Cloud
Divides one physical resource into multiple isolated environments for independent workloads.	Delivers IT resources as services over a network.

---

1.2 Key Characteristics of Cloud

1. On-Demand Self-Service
2. Broad Network Access
3. Rapid Elasticity & Scalability
4. Measured Service (Pay-as-you-go)

---

1.3 On-Premises vs Cloud

	On-Premises	Cloud
Cost	Resources are often underutilized outside peak times.	May involve upfront costs but offers long-term savings.
Flexibility	Hard to scale quickly.	Easily scalable up or down as needed.
Availability	Requires redundancy and backups for reliability.	High reliability with providers publishing SLAs (Service Level Agreements).
Deployment Speed	Time-consuming planning and setup.	Rapid deployment with ready-to-use infrastructure.

---

2. Cloud Service Models

IaaS (Infrastructure as a Service)	PaaS (Platform as a Service)	SaaS (Software as a Service)
Provides computing resources like servers and storage.	Offers platforms for developing and deploying applications.	Delivers software applications over the internet.

• DaaS (Desktop as a Service): Provides desktop environments via the cloud.
• XaaS (Everything as a Service): A broad concept where virtually everything is offered as a service.

---

3. Cloud Deployment Models

• Public Cloud: Shared infrastructure accessible by the general public.
• Private Cloud: Exclusive cloud infrastructure for a single organization.
• Multi-Cloud: Combines multiple public clouds or public + private clouds.
• Community Cloud: Shared by several organizations with common interests.
• Edge Cloud: Processes data close to where it’s generated.
• Hybrid Cloud: Mix of public and private cloud environments.

---

4. Core Cloud Services and Concepts

---

4.1 Virtual Server Services

• Virtual servers act like independent machines but run as software-based virtual instances on physical hardware.
• A hypervisor manages hardware resources to create and run virtual machines (VMs).

---

4.2 Key Cloud Concepts

• Data Center: Facilities housing many servers connected by high-speed networks.
• Region: Geographical location of data centers.
• Availability Zone: A single data center; multiple zones exist in one region.
• Scale Out/In: Horizontal scaling (adding/removing servers).
• Scale Up/Down: Vertical scaling (changing specs of a single server).

---

4.3 Storage Types

• File Storage: Hierarchical structure with folders and files.
• Block Storage: Stores data in blocks; ideal for high-performance workloads like databases.
• Object Storage: Stores data as objects with unique IDs and metadata; excellent for unstructured data and scalability.

---

5. Technologies Enabling Cloud Computing

Cloud services, especially IaaS, rely on virtualization across servers, networks, and storage.

---

5.1 Types of Virtualization

Type	Description
Hypervisor-based Virtualization	Hypervisor runs directly on hardware without a host OS.
Host OS-based Virtualization	Hypervisor runs as software on top of a host OS.
Container Virtualization	Divides a single OS into isolated environments for lightweight app deployment.

---

Feature	Hypervisor-based	Host OS-based	Container Virtualization
Host OS Needed	No	Yes	Yes
OS Installation	Each VM runs its own OS	Each VM runs its own OS	One OS shared among containers
Speed	Fast	Slower	Very fast
Resource Efficiency	Good	Lower	Very high
Isolation Level	Very high	High	Lower (shares kernel)
Use Cases	Data centers, enterprise virtualization	Personal testing, dev environments	Microservices, DevOps

---

5.2 Other Key Technologies

• OpenStack: Open-source cloud infrastructure management platform, providing IaaS capabilities for compute, storage, and networking.
• HCI (Hyper-Converged Infrastructure): Integrates compute, storage, and virtualization into a single platform.
• PaaS Enabling Tech:
  • Docker: Creates and runs containers.
  • Container Orchestration: Tools like Kubernetes manage many containers automatically.

---

6. Cloud-Native Technologies

• Containers: Package apps with dependencies for consistent execution.
• Container Orchestration: Manages large numbers of containers across clusters (e.g., Kubernetes).
• DevOps: Bridges development and operations for faster, automated workflows.
• CI/CD: Automates integration, testing, and deployment processes.
• MSA (Microservices Architecture): Breaks large applications into smaller, independent services.

---

7. Cloud Native Architectures

---

7.1 Monolith vs. Microservices

Aspect	Monolith	Microservices
Structure	Single large app	Many small independent services
Deployment	Entire app redeployed	Independent deployment of services
Speed	Fast at first, slower as complexity grows	Faster due to team autonomy
Failure Impact	One failure affects the whole system	Failures isolated to individual services
Tech Stack	Unified across the app	Services can use different tech stacks
Testing	Easier integrated testing	Requires contract testing between services
Complexity	Simpler initially	Higher due to distributed systems

---

7.2 Kubernetes

Kubernetes is a powerful container orchestration platform that provides:

• Automated Deployment
• Scaling and Load Balancing
• Self-Healing (Automatic Recovery)
• Rolling Updates without downtime

---

7.3 DevOps + CI/CD

Combining DevOps practices with CI/CD pipelines enables rapid, automated, and reliable software delivery in cloud-native environments.

---

⭐ Summary

Cloud computing makes IT resources accessible on demand, offering flexibility, scalability, and cost efficiency. Modern architectures like microservices, coupled with technologies like Kubernetes, empower organizations to innovate rapidly and operate at scale.