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CAP theorem is one of those ideas everyone knows, but very few actually design with. And that’s because it’s usually taught as a formula, not as a pressure situation. So let’s do this the system designer way. Assume you’re building a distributed system. Not a single server, not a single database. Multiple nodes, multiple machines, talking over a network. The moment you distribute a system, one thing becomes inevitable: things will fail. Machines crash. Networks slow down. Packets get lost. You don’t get to opt out of this. ...

Let’s talk about Event Driven Architecture. Imagine you are building an e-commerce platform. A customer places an order. What all should happen? Payment should be processed. Inventory should be updated. Email confirmation should be sent. Analytics should record the purchase. Maybe fraud detection should run. Now tell me honestly, should Order Service directly call all these services one by one? What happens if Email Service is down? Should order placement fail? What if Analytics is slow? Should customer wait? This is where tight coupling starts hurting. ...

Let’s talk about microservice architecture Look at the diagram first. Don’t read labels yet. Just observe the flow. A client sends a request. That request does not directly hit business logic. It first goes through an API Gateway. From there, the request fans out to multiple independent services, and those services interact with the database. That structure itself tells a story. Now let’s rewind and start from the problem. ...

Amazon WorkSpaces (Managed Desktop as a Service – DaaS) Definition Amazon WorkSpaces is a fully managed Desktop-as-a-Service (DaaS) offering from AWS. Allows users to provision Windows or Linux virtual desktops in the AWS Cloud. Purpose Replaces on-premises Virtual Desktop Infrastructure (VDI) solutions. Provides a secure, scalable, and cost-effective way to deliver desktop environments to users. Key Features Managed DaaS: AWS manages the infrastructure, storage, and desktop provisioning. Platform Support: Supports both Windows and Linux desktops. Security: Integrated with AWS KMS for encryption and can operate within a VPC for network isolation. Pay-as-you-go Pricing: Pay only for the desktops you use (hourly or monthly). Remote Access: Users can securely connect from anywhere (home, office, etc.) to their cloud desktop. Use Case Example A company wants to give employees secure remote access to corporate resources without managing physical laptops or VDI infrastructure. IT admins provision WorkSpaces for employees to access internal systems securely via the cloud. Performance and Latency Minimize latency by deploying WorkSpaces in regions closest to end users. Example: U.S. office → Deploy WorkSpaces in a U.S. region. European office → Deploy WorkSpaces in a European region. General Rule: For any AWS application, deploy resources close to users to improve performance and reduce latency. Exam Tips If you see keywords like: “Managed desktop in the cloud” “Virtual Desktop Infrastructure (VDI) replacement” “Secure Windows/Linux desktops for remote users” Remember: WorkSpaces = Managed Virtual Desktops in AWS Cloud Amazon AppStream 2.0 Definition Amazon AppStream 2.0 is a fully managed desktop application streaming service. It allows users to stream individual desktop applications to any device through a web browser, without installing or managing infrastructure. Purpose Designed for application delivery, not full desktops. Lets users access software like Blender, Eclipse, OpenOffice, Firefox, etc., directly in a browser. Removes the need for local installations or on-premises servers. Key Features Application-Focused: Streams specific apps, not entire desktops. Browser-Based Access: Users access apps via any device with a web browser. No Infrastructure Setup: AWS handles scaling, maintenance, and provisioning. Customizable Performance: Configure instance types per application (e.g., more CPU/GPU for Photoshop or Blender). Scalable and Secure: Easily supports multiple users, securely managed through AWS. Comparison: AppStream 2.0 vs WorkSpaces Feature Amazon WorkSpaces Amazon AppStream 2.0 Type Desktop-as-a-Service (DaaS) Application Streaming Service Purpose Provides full Windows/Linux desktops Streams single applications Access Via remote desktop client Via web browser Use Case Virtual desktop for users Delivering apps without local installs Example Full desktop for remote employees Running Blender or Photoshop in browser Use Case Example An organization wants employees or students to use desktop applications remotely (e.g., 3D modeling or coding tools) without installing them locally. They use AppStream 2.0 to stream these applications through a web browser on any device. Exam Tips Keywords like “stream applications,” “run desktop apps in a browser,” or “no full desktop environment” point to Amazon AppStream 2.0. Remember: WorkSpaces = Full virtual desktop (VDI) AppStream 2.0 = Application streaming to browsers IoT Core Overview AWS IoT Core lets connected devices (sensors, appliances, etc.) communicate securely with AWS services. Supports MQTT, HTTP, and WebSockets for messaging. Enables real-time data ingestion, device management, and rule-based data routing. Example: Sending temperature data from IoT sensors to AWS Lambda or DynamoDB. Elastic Transcoder Overview Amazon Elastic Transcoder converts (transcodes) media files from one format to another for playback on various devices. Fully managed and scalable. Example: Convert uploaded videos in S3 to mobile-friendly MP4 versions. (Note: AWS MediaConvert is the modern replacement, but Elastic Transcoder still appears in CCP-level content.) AppSync AWS AppSync is a managed GraphQL API service that allows applications to query and update data in real time across multiple data sources (DynamoDB, Lambda, RDS, etc.). Automatically handles data synchronization and offline access. Example: A mobile app fetching user data through a single GraphQL endpoint. Amplify AWS Amplify helps developers build, deploy, and host full-stack web and mobile applications quickly. Integrates with backend services like AppSync, Cognito, S3, and Lambda. Example: Rapidly building a React web app with AWS backend resources automatically configured. AWS Infrastructure Composer AWS Infrastructure Composer is a visual tool for designing and deploying AWS architectures using drag-and-drop components. Generates Infrastructure as Code (IaC) templates (CloudFormation or CDK). Speeds up architecture prototyping and deployment. Device Farm Overview AWS Device Farm is an app testing service that lets you test Android, iOS, and web apps on real physical devices in the AWS Cloud. Identifies issues across devices and operating systems. Example: Automatically testing a mobile app on multiple phone models. AWS Backup Overview AWS Backup provides centralized, automated backup management across AWS services (EBS, RDS, DynamoDB, EFS, etc.). Supports backup policies, retention rules, and cross-region backup. Ensures data protection and compliance. Disaster Recovery Strategies AWS defines several Disaster Recovery (DR) strategies, based on cost vs recovery speed: ...

AWS STS (Security Token Service) Overview AWS STS is a core AWS service used to create temporary, limited-privilege credentials for accessing AWS resources. These credentials are short-term and consist of: Access Key ID Secret Access Key Session Token (time-limited) Purpose Provides temporary security credentials instead of long-term IAM user credentials. Commonly used when: Access must be limited in time or scope. Cross-account access is required. Federated users (from external identity systems) need AWS access. Applications or EC2 instances assume roles to access AWS services securely. How It Works A user or service assumes a role using an STS API call (for example, AssumeRole). STS returns temporary credentials (access key, secret key, session token). These credentials are used to access AWS resources as defined by the role’s permissions. Credentials expire automatically after a specified duration. Key Use Cases Identity Federation Users managed in an external system (e.g., corporate directory, SSO provider) can obtain STS tokens to access AWS resources. Allows integration with systems like Active Directory, Google Workspace, or SAML providers. Cross-Account Role Access Allows an IAM user in one AWS account to assume a role in another account. Facilitates secure sharing of resources between AWS accounts. EC2 Instance Roles EC2 instances can assume IAM roles automatically. AWS refreshes credentials in the background using STS to maintain temporary access tokens. ...

AWS Organizations Global Service used to manage multiple AWS accounts centrally. The main account is called the Master Account, and other linked accounts are Child Accounts. Key Benefits Consolidated Billing All accounts share a single payment method managed by the master account. You receive one combined bill for all linked accounts. Pricing Benefits Aggregated usage provides volume discounts for services like EC2 and S3 across all accounts. Reserved Instances (RIs) are shared among accounts for maximum savings. Automation API support to automate AWS account creation (useful for sandbox or departmental accounts). Service Control Policies (SCPs) Used to restrict account privileges. Common exam topic. Multi-Account Strategy Why Use Multiple Accounts Easier management and security isolation. Organize by: Department (Sales, Finance, HR) Environment (Dev, Test, Prod) Project (Project-1, Project-2, etc.) Regulatory requirements (compliance-based isolation) Benefits Separate service limits per account. Improved resource isolation (different VPCs per account). Dedicated logging accounts for central log management. Best Practices Apply tagging standards across accounts for billing. Enable CloudTrail and CloudWatch Logs in all accounts. Send logs to a central S3 or logging account for visibility and compliance. Organizational Units (OUs) Used to group related accounts within an organization. Structure Example: Root OU (contains Master Account) Dev OU, Prod OU, etc. Nested OUs possible (e.g., Prod → Finance OU, HR OU). Allows hierarchical policy management using SCPs. Service Control Policies (SCPs) Manage permissions centrally across accounts. Whitelist or blacklist IAM actions at OU or account level. Do not apply to the Master Account. Behavior Affect users and roles (including root users) within child accounts. Do not affect service-linked roles (used internally by AWS services). SCPs must have explicit “Allow” statements; otherwise, actions are denied by default. Use Cases Restrict access to specific AWS services (e.g., deny EMR in production). Enforce compliance (e.g., disable non-PCI-compliant services). Examples Blacklist example: 1 2 3 4 5 { "Effect": "Deny", "Action": "dynamodb:*", "Resource": "*" } Denies all DynamoDB actions. Whitelist example: 1 2 3 4 5 { "Effect": "Allow", "Action": ["ec2:*", "cloudwatch:*"], "Resource": "*" } Allows only EC2 and CloudWatch actions; all others denied. Key Exam Points AWS Organizations = Global Service for multi-account management. Master account pays bills via Consolidated Billing. Aggregated usage and shared RIs reduce costs. SCPs manage account-level permissions, not IAM roles directly. SCPs don’t apply to the master account or service-linked roles. Use CloudTrail and centralized logging for auditing all accounts. AWS Organizations – Consolidated Billing Purpose Consolidated Billing in AWS Organizations allows centralized payment management and shared cost benefits across multiple AWS accounts under one organization. ...

Machine Learning Overview Machine Learning (ML) is not deeply tested in the CCP exam. You only need to understand main AWS ML services and their high-level use cases. Amazon Rekognition Definition: A machine learning-based image and video analysis service that can automatically detect and recognize objects, people, text, scenes, and activities. Core Features / Capabilities: Object and Scene Detection: Identifies items in images or videos (e.g., person, dog, mountain bike). Facial Analysis: Detects faces and analyzes attributes like gender, age range, and emotion. Face Search and Verification: Compares faces for user verification or security applications. Celebrity Recognition: Identifies well-known people in images or videos. Text Detection: Extracts text from images (useful for reading signs, runner numbers, etc.). Content Moderation: Flags inappropriate or unsafe content. Pathing / Movement Tracking: Tracks object or person movements (e.g., in sports or surveillance). Use Cases: ...

AWS Security & Compliance Shared Responsibility Model Definition: The framework that defines which security tasks are handled by AWS and which are managed by the customer. Key Idea: AWS is responsible for security of the cloud. Customer is responsible for security in the cloud. AWS Responsibility (Security of the Cloud) AWS manages and secures: Infrastructure: Hardware, software, networking, facilities. Managed Services: Full responsibility for services like S3, DynamoDB, RDS. Global Infrastructure: Regions, Availability Zones (AZs), and Edge Locations. Compute, Storage, Database, and Networking layers of their services. Service Software: Ensuring AWS services are updated, secure, and operational. Example: For RDS, AWS handles: ...

VPC & Networking (Overview) What is a VPC? VPC (Virtual Private Cloud) is a private, isolated section of the AWS cloud where you can launch and manage your AWS resources (like EC2, RDS, etc.). It provides control over networking, including IP addressing, subnets, routing, and security. Think of it as your own virtual data center in AWS. Why VPC Matters VPC concepts are essential for networking-related AWS services. In-depth knowledge is required for advanced certifications such as: AWS Certified Solutions Architect – Associate AWS Certified SysOps Administrator – Associate For CCP, understanding high-level concepts and their purpose is sufficient. Key Components to Know (for CCP) Component Purpose / Function VPC The virtual private network environment in AWS. Subnets Divide a VPC into smaller networks; can be public (internet-accessible) or private. Internet Gateway (IGW) Allows communication between resources in a public subnet and the internet. NAT Gateway Enables outbound internet access for private subnets without exposing them publicly. Security Groups Act as stateful firewalls controlling inbound and outbound traffic at the instance level. Network ACLs (NACLs) Stateless firewalls controlling traffic at the subnet level. VPC Flow Logs Capture network traffic information for monitoring and troubleshooting. VPC Peering Connects two VPCs privately using AWS’s internal network. VPC Endpoints Enable private connectivity to AWS services (like S3, DynamoDB) without using the internet. Site-to-Site VPN Connects an on-premises network to a VPC over the internet securely. Direct Connect Establishes a dedicated physical connection between on-premises and AWS for low latency. Transit Gateway Central hub to connect multiple VPCs and on-premises networks efficiently. CCP Exam Relevance The VPC topic accounts for less than 1–2 questions on the exam. Focus on definitions, purposes, and relationships between components. Hands-on familiarity with the default VPC (created automatically by AWS) is helpful. Key Takeaways Understand what each component does and why it’s used. No need to configure or design a VPC for the CCP level. Exam tests conceptual clarity, not technical implementation. IP Addresses in AWS IPv4 Overview IPv4 (Internet Protocol version 4) provides around 4.3 billion unique addresses. Common format: 192.0.2.1 (four octets). Used for most existing networks and devices. Public IPv4 Public IPs are reachable over the internet. Assigned automatically when creating EC2 instances (if enabled). Behavior: Released when instance is stopped. A new public IP is assigned when instance is started again. Pricing: AWS charges $0.005/hour per public IPv4 address (including Elastic IPs). Free Tier: 750 hours of public IPv4 usage per month. Private IPv4 Used for internal communication within private networks (e.g., inside a VPC). Example range: 192.168.0.0/16. Not accessible from the internet. Remains the same for an EC2 instance’s entire lifetime, even after stop/start. Elastic IP (EIP) A static public IPv4 address that remains the same even if an instance is stopped and restarted. Useful for consistent IP mapping (e.g., DNS records). Charged if allocated but not associated with a running instance. IPv6 Overview IPv6 (Internet Protocol version 6) is the newer protocol with 3.4 × 10³⁸ addresses (virtually unlimited). Example format: 2600:1f18:abcd:1234::1. All IPv6 addresses are public (no private range). Free to use in AWS (no hourly charge). IPv4 vs IPv6 (Quick Comparison) Feature IPv4 IPv6 Address Space 4.3 billion 3.4 × 10³⁸ Format 4 decimal octets (e.g., 192.168.0.1) Hexadecimal blocks (e.g., 2600:1f18::1) Private Range Yes No Internet Reachability Optional Always Public AWS Cost $0.005/hour Free Example Usage Legacy systems, internal networking New apps, scalable internet exposure Exam Tip Know the difference between public, private, and elastic IPs. Remember: IPv6 = free + public-only + huge address space. For CCP, focus on behavior and cost, not configuration details. VPC (Virtual Private Cloud) Overview Definition VPC (Virtual Private Cloud) is a private, isolated network in AWS used to deploy cloud resources like EC2 instances, databases, etc. Each VPC is region-specific. If you use multiple AWS Regions, you have separate VPCs in each region. VPC Structure A VPC contains subnets, which are partitions of the VPC network. Each subnet is associated with one Availability Zone (AZ). CIDR Range (Classless Inter-Domain Routing) defines the IP address range of a VPC. Example: 10.0.0.0/16. ...

Cloud Monitoring Cloud Monitoring helps understand and visualize the performance and health of AWS resources. The main AWS service for monitoring is Amazon CloudWatch. CloudWatch Metrics Definition Metrics: Variables that represent the performance of AWS resources over time. Examples: CPUUtilization (for EC2) NetworkIn and NetworkOut Billing (total AWS spending) Key Points Metrics are timestamped data points collected periodically. You can visualize metrics in CloudWatch Dashboards. Billing Metric: Available only in us-east-1 region. Represents total AWS spending for the entire account. Resets monthly. Common Metrics by Service Service Common Metrics Notes EC2 CPUUtilization, StatusCheck, NetworkIn/Out RAM metrics are not available EBS DiskReadOps, DiskWriteOps Measures disk I/O S3 BucketSizeBytes, NumberOfObjects, AllRequests Tracks storage and request activity Billing EstimatedCharges Account-wide billing data (us-east-1) Service Limits API usage Helps monitor resource limits Custom Metrics User-defined Push your own metrics if needed Metric Frequency Standard Monitoring: every 5 minutes (default, free). Detailed Monitoring: every 1 minute (paid). CloudWatch Alarms Alarms trigger actions based on metric thresholds. Example: When CPU utilization > 90%, send an alert. Alarm Actions Auto Scaling Actions – increase/decrease EC2 instance count automatically. EC2 Actions – stop, terminate, reboot, or recover instances. SNS Notifications – send alerts via email, SMS, or other channels. Billing Alarms Set alarms on the Billing metric to get notified when estimated charges exceed a certain amount (e.g., $10 or $20). Alarm States State Meaning OK Metric within normal range INSUFFICIENT_DATA Not enough data points ALARM Threshold breached (bad condition) Evaluation Options You can configure: Statistic type (average, min, max, percentage) Evaluation period (e.g., 5 minutes, 1 hour) Summary CloudWatch Metrics track performance data. CloudWatch Alarms automate responses or notifications when thresholds are crossed. Billing Metrics and Alarms help control costs. Custom Metrics allow monitoring of user-defined data. Amazon CloudWatch Logs Purpose CloudWatch Logs is used to collect, monitor, store, and analyze log files from various AWS services and on-premises systems. Enables real-time monitoring and troubleshooting of applications and infrastructure. What Are Log Files? Logs are records of events and activities generated by applications or systems. Used for debugging, troubleshooting, and performance analysis. Example: logs that record user actions, errors, cleanup tasks, or background processes. Log Sources CloudWatch Logs can collect logs from: ...