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☁️ VPC Network

  ☁️ VPC Network — Simple Notes 1. What is a VPC? VPC (Virtual Private Cloud) is a virtual version of a physical network inside Google Cloud. Think of it like your company's private network in the cloud . It provides connectivity for: Compute Engine VM instances Google Kubernetes Engine (GKE) clusters App Engine Flexible Other Google Cloud services that use Compute Engine VMs Simple example: Google Cloud │ ┌────▼────┐ │ VPC │ └────┬────┘ ┌──────────┼──────────┐ ▼ ▼ ▼ VM VM GKE 2. VPC and Load Balancing VPC supports Google's internal networking and load-balancing systems. It can provide: Internal pass-through Network Load Balancers Internal proxy-based Application Load Balancers Connectivity for external load balancers to their backend services Think: Users │ ▼ External Load Balancer │ ▼ ...
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Citi System Design Interview Questions for Software Engineers.

  Citi System Design Interview Questions for Software Engineers. 200+ million customer accounts. 160+ countries. Roughly $5 trillion moving through the network daily. Every one of those transactions is a distributed systems problem, with a regulator watching. 1. How would you design the core ledger system that guarantees no transaction is ever double-counted across millions of accounts? 2. How would you design real-time fraud detection for card transactions without adding noticeable latency at checkout? 3. How would you architect cross-border payment processing across currencies, correspondent banks, and SWIFT messaging? 4. How would you design a system for regulatory transaction reporting that must stay auditable years later? 5. How would you handle eventual consistency between a customer's mobile balance and the core banking system of record? 6. How would you design multi-region failover for a payments platform when data residency rules restrict where customer data can live? 7. ...
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GCP Compute Engine — Common VM Actions

  GCP Compute Engine — Common VM Actions 1. VM Metadata Every Compute Engine VM has a metadata server . Think of it as: Metadata server = a place where a VM can get information about itself. For example, a VM can retrieve information such as: VM name Zone Region Internal IP External IP Other instance information Why is this useful? It is especially useful with startup scripts and shutdown scripts . For example: VM starts ↓ Startup script runs ↓ Script asks Metadata Server: "What is my external IP?" ↓ Metadata Server returns the IP ↓ Script uses that IP The important part is that the script doesn't need you to manually enter the VM's IP address . Example Suppose you create 10 VMs. Instead of writing: VM1 → use 34.x.x.x VM2 → use 35.x.x.x VM3 → use 34.x.x.x you can create one reusable startup script : Get my external IP from metadata ↓ Use that IP to configure the application The same script can run on every VM. Key...
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Disk Concept -Boot Disk and Persistent Disk

  Google Cloud — Easy Study Notes Essential Google Cloud Infrastructure: Foundation 1. What is Google Cloud? Google Cloud is basically a collection of computing, storage, networking, database, security and other IT services provided by Google. Instead of buying physical servers yourself, you can rent/use Google's infrastructure. Simple example Traditional company: Company ↓ Buy physical servers ↓ Install OS ↓ Configure network ↓ Maintain hardware ↓ Run application Google Cloud: You ↓ Choose Google Cloud service ↓ Configure it ↓ Run your application Google manages the underlying physical infrastructure. 2. Cloud Computing — Basic Idea Cloud computing means: Using computing resources over the internet instead of owning all the physical hardware yourself. You can get: CPU RAM Storage Network Databases Kubernetes Application platforms Security services when you need them. 3. Google Cloud Projects A Project is one of the most important concepts in Google Cloud. Think of a...
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