Tech-Reader.blog

  AWS Under Real Load: Event Notification Fan-Out Storms in Amazon S3 # AWS # S3 # Serverless # CloudOps A production-grade diagnostic and prevention guide for cascading compute bursts and system instability caused by high-volume S3 event notifications. Problem A system that relies on S3 event notifications begins experiencing: Sudden Lambda concurrency spikes Increased SQS queue depth Rising processing latency Downstream timeouts Unexpected cost surges No visible S3 errors PUT and DELETE operations succeed. But the compute layer destabilizes. The storage tier looks healthy. The event-driven tier is overwhelmed. Clarifying the Issue S3 Event Notifications trigger downstream services for object events such as: s3:ObjectCreated:* s3:ObjectRemoved:* s3:ObjectRestore:* Under light traffic, this works seamlessly. Under heavy object churn, each object operation generates an event. High ingestion rates or mass deletes create: One object → one event 10,000 objects → 10,000 events 1 million...

  The Secret Life of AWS: Network Isolation (VPC & Security Groups) # AWS # VPC # Security # DevOps Why your database shouldn't have a public IP address. Part 42 of The Secret Life of AWS Timothy was proud of his new microservice. He had successfully connected his serverless application to an Amazon RDS PostgreSQL database. "The latency is great," Timothy told Margaret, bringing up his dashboard. "I can query the database directly from my local machine using pgAdmin, and the application connects perfectly." Margaret leaned in and looked at the connection string on his screen. Host: checkout-db.c3x...us-east-1.rds.amazonaws.com She opened the AWS Console, navigated to the RDS instance, and checked the network settings. Publicly Accessible: Yes Security Group Inbound Rules:   PostgreSQL (5432) | Source: 0.0.0.0/0 Margaret sighed. "Timothy, your database is sitting on the public internet." "I know," Timothy said. "I had to set it to ...

The Secret Life of Azure: The Library That Copied Itself # Azure # FrontDoor # GlobalScale # DevOps Scaling globally with Azure Front Door and Edge Networking. Resilience & Release The library was packed, and Timothy was looking at a stack of letters from patrons in London, Tokyo, and Sydney. They all had the same complaint: the library was "too slow." "Margaret," Timothy said, "I don't understand. Our servers are fast, our code is optimized, and our database is healthy. But a user in Australia says it takes forever just to see the front page. Are we hitting a limit on how many people can fit in the building?" Margaret picked up a piece of chalk and drew a single dot on one side of the board and a tiny stick figure on the far opposite side. "The problem isn't the building, Timothy. It's the  distance . Information can only travel so fast. If your library is in Texas and your patron is in Tokyo, the data has to cross oceans and thousand...

  The Secret Life of JavaScript: The Catch # JavaScript # Coding # Programming # SoftwareDevelopment How stack unwinding works, and the mechanical truth of  throw . Timothy was staring at a wall of red text in his console. The words  Uncaught TypeError  glared back at him. His application had been working flawlessly for days. It was fetching users, parsing data, and rendering profiles. But today, the database had returned a single corrupted record without a  firstName  property, and the entire application had collapsed. "It just died," Timothy said, rubbing his eyes. "One missing property, and the whole system stopped running." Margaret pulled up a chair and grabbed a dry-erase marker. "You are programming for the Happy Path, Timothy. You are assuming the network is perfectly reliable and the data is always clean. Let's look at what actually happens when a function fails." The Call Stack Margaret drew three boxes on the whiteboard, stacking them on top...

  'AccessDeniedException' During Cross-Account Rekognition Call ('sts:AssumeRole' Failure) # AWS # AmazonRekognition # IAM # CloudSecurity Why  sts:AssumeRole  fails when identity and trust policies don’t align across AWS accounts Category: IAM & Permission Boundaries Problem Your application runs in  Account A . Rekognition resources (or the S3 bucket feeding Rekognition) live in  Account B . Your code attempts to assume a role in Account B before calling  Amazon Rekognition . The call fails with one of the following: AccessDeniedException: User is not authorized to perform: sts:AssumeRole or AccessDeniedException: User is not authorized to perform: rekognition:DetectLabels IAM policies look correct in both accounts. Still denied. Clarifying the Issue Cross-account access requires  two separate permission grants : The caller in Account A must be allowed to call  sts:AssumeRole . The target role in Account B must trust Account A in its trust p...