CAP/CAPLEC Theorem Kafka Redis - LRU, LFU, Redis Cluster, Distributed Locks Read Replica Elastic Search Binary Tree - Indexing 2PL, OCC, MVCC, lazy writes Connection Pooling, PGBounce...

Why this whole topic exists In a single-machine program, “failure” usually means a crash. You see a stack trace, you fix it, you restart. Easy. In a distributed system, failure is the default sta...

Why this whole topic exists Picture a single computer running one program. Memory has one copy of every variable, the CPU executes instructions one at a time, and a write you just made is immediat...

What It Is Scalability is the ability of a system to handle an increasing workload, either by adding more resources (scaling out) or by upgrading the capacity of existing resources (scaling up). I...

Starting Point A single MySQL instance handling all reads and writes. As traffic grows, this becomes the bottleneck. The following sections cover the optimizations — in the order you would actuall...

Load Balancer Why it was needed: In early web architectures, applications ran on a single, powerful server. As traffic grew, vertical scaling (buying bigger hardware) hit physical limits and becam...

KMS, Secrets Management, CI/CD & Cost Optimisation Mid-Level SRE/DevOps/Platform Interview Notes 1. AWS KMS — Key Management Service Why KMS Exists Every encryption service in AWS — EBS vo...

Writing Comments ””” Some comments being written in python “”” ’’’ We can use single quotes as well ‘’’ Printing print("Hello", "World", sep="-", end="!") Range range(5) range(5,10) range(5,...

Table of Contents What is Jenkins? Core Architecture Jobs and Pipelines Jenkinsfile — Declarative vs Scripted Pipeline Stages, Steps & Agents Build Triggers Credentials & Se...

Q. Finding logs -> Via grep and python Searching for Internal Server Logs python``` import re pattern = r”\b5\d{2}\b” with open(‘f.txt’, ‘r’) as f: for line in f: if re.search(pat...