System Architecture and DevOps Vocabulary

This set of vocabulary flashcards covers key concepts in system architecture, communication patterns, database integrity, and DevOps infrastructure based on the provided lecture notes.

WebSockets or SSE

A technology that keeps a persistent connection open between the backend and frontend for instant, real-time data flow.

Idempotency Keys

Unique Request IDs used by a server to identify and ignore duplicate actions, ensuring a system doesn't process the same transaction twice.

Asynchronous Processing

A method for handling heavy tasks where the API returns a 'Success' immediately and moves the actual task to a Message Queue.

Circuit Breaker Pattern

An architectural pattern that automatically 'fails fast' when a third-party API is broken to prevent the main application from crashing and to save server resources.

Statelessness

An architectural design where session data is stored in a centralized location like Redis rather than server memory, allowing any server to handle any request.

Indexing & Caching

Methods to speed up database performance without increasing hardware by optimizing query plans and storing 'hot' data in Redis.

Connection Pool Exhaustion

A state where an API is slow because all available database connections are in use, even if CPU and RAM resources appear healthy.

Salted Hashing (bcrypt)

The industry-standard one-way function used to store passwords so they cannot be decrypted into plain text.

Thundering Herd (and Jitter)

A problem where many users hit a database simultaneously after a cache expires; solved by 'Jitter', which staggers cache expiry times.

Soft Deletes

The practice of using a flag (like deleted_at) to hide data instead of permanently removing it from the database to maintain data integrity.

HPA (Horizontal Pod Autoscaler)

A scaling method that handles traffic spikes by adding more server instances to the system.

VPA (Vertical Pod Autoscaler)

A scaling method that handles traffic by increasing the resource capacity (CPU/RAM) of an existing server.

Cold Start

An initialization delay in serverless computing (like AWS Lambda) where the cloud provider must boot the code after it has been idle.

FaaS (Function as a Service)

A serverless computing model where you pay only for the actual execution time of code rather than for 24/7 server idle time.

Containerization (Docker)

The process of packaging code with its exact environment to ensure it runs consistently across different machines and the cloud.

Blue-Green Deployment

A release strategy that maintains two parallel environments to route traffic to a new version only when it is fully ready, ensuring zero downtime.