Complete Q4

q4-scalability/calculations.md

@@ -1,55 +1,58 @@
-# Scalability and Load Balancing
+# Q4 - Scalability and Load Balancing
 
-## 1. Required Number of Containers
+## 1. Architecture Overview
 
-### Given
+The application is deployed behind a Load Balancer that distributes incoming traffic across multiple application containers.
 
-- Incoming traffic = **15,000 requests/second**
+Components:
-- One container can handle = **500 requests/second**
-- Safety margin = **30%**
 
-### Calculation
+- Users
-
+- Load Balancer
-Required containers without margin:
+- Container Cluster
-
+- Ghaymah Block Storage
-15000 ÷ 500 = **30 containers**
+- Database
-
-Adding a 30% safety margin:
-
-30 × 1.30 = **39 containers**
-
-Rounded up:
-
-**40 containers**
 
 ---
 
-## 2. Cold Start Strategy
+## 2. Required Number of Containers
 
-To reduce startup delays during traffic spikes, the following strategy is recommended:
+Application Load = 15,000 requests/second
 
-- Keep at least 2 containers always running.
+One Container Capacity = 500 requests/second
-- Enable Horizontal Pod Autoscaler (HPA).
+
-- Cache container images on cluster nodes.
+Required Containers:
-- Use lightweight Docker images.
+
-- Configure Readiness Probes before sending traffic to new containers.
+15000 / 500 = 30 Containers
-- Scale gradually to avoid resource spikes.
+
+Safety Margin (30%):
+
+30 × 1.30 = 39 Containers
+
+Final Answer:
+
+**39 Containers**
 
 ---
 
-## 3. Using Ghaymah Block Storage
+## 3. Cold Start Strategy
 
-Ghaymah Block Storage should be used for stateful workloads that require persistent storage.
+To reduce cold start latency:
 
-Examples include:
+- Keep a small number of warm containers running.
+- Enable Auto Scaling based on CPU and request rate.
+- Perform health checks before routing traffic.
+- Register new containers with the Load Balancer only after becoming healthy.
+- Use lightweight container images for faster startup.
 
-- PostgreSQL
+---
-- MySQL
+
-- MongoDB
+## 4. Ghaymah Block Storage
+
+Block Storage is used for stateful workloads such as databases.
 
 Benefits:
 
-- Data persists even if a container restarts.
+- Data persists even if containers restart.
-- High reliability.
+- Supports high availability.
-- Easy storage expansion.
+- Can be attached to replacement containers.
-- Suitable for production databases.
+- Suitable for MySQL, PostgreSQL, MongoDB and other databases.