标签：#infrastructure

Understanding the 550 SPF Check Failed Error The "550 SPF Check Failed" error indicates that a receiving mail server rejected an incoming email. This rejection occurs because the sender's domain failed its Sender Policy Framework (SPF) validation. SPF is an email authentication protocol defined in RFC 7208 . SPF helps prevent email spoofing. It allows domain owners to specify which mail servers are authorized to send email on behalf of their domain. Receiving mail servers perform an SPF check by querying the sender's DNS for an SPF TXT record. If the sending server's IP address is not listed in the domain's SPF record, the SPF check fails. The receiving server then rejects the email based on its configured policy, often resulting in a 550 error. This error protects recipients from unauthorized emails and enhances email security. Initial Diagnosis: Identifying the Root Cause Diagnosing an SPF failure requires examining the bounce message and the domain's DNS records. The bounce message often provides specific details about the SPF failure. Look for phrases like "SPF validation failed," "unauthorized sender," or "IP address not permitted." Common reasons for a 550 SPF Check Failed error include: Missing SPF Record: No SPF TXT record exists for the sending domain. Incorrect SPF Syntax: The SPF record contains errors, making it unreadable or invalid. Incomplete SPF Record: The SPF record does not list all legitimate sending IP addresses or hostnames. DNS Lookup Limit Exceeded: The SPF record requires more than 10 DNS lookups, violating RFC 7208. DMARC Policy Enforcement: A DMARC (Domain-based Message Authentication, Reporting, and Conformance) policy ( RFC 7489 ) with p=reject or p=quarantine is in place, enforcing strict SPF failure handling. To begin diagnosis, use our SPF checker to verify your domain's SPF record and its validity. This tool quickly identifies syntax errors and lookup issues. Step-by-Step Troubleshooting and Resolution Resolving SPF failures involves

Introduction to DMARC and the p=quarantine Policy DMARC (Domain-based Message Authentication, Reporting, and Conformance), defined in RFC 7489 , is an email authentication protocol. It builds upon SPF and DKIM to provide domain owners with the ability to protect their domain from unauthorized use. DMARC enables senders to specify how receiving mail servers should handle unauthenticated emails originating from their domain. It also provides a mechanism for receiving servers to report back to the domain owner about authentication results. DMARC policies dictate the action receiving mail servers should take when an email fails DMARC authentication. The three primary policies are: p=none : Monitor mode. Receiving servers take no action on failed messages but send reports. This is the initial deployment phase. p=quarantine : Receiving servers should treat failed messages as suspicious. They are typically placed in the recipient's spam folder or flagged for further review. p=reject : Receiving servers should outright reject messages that fail DMARC authentication. This is the strongest enforcement policy. Implementing p=quarantine is a critical step towards full domain protection. It allows domain owners to mitigate spoofing and phishing attempts without immediately blocking legitimate, but misconfigured, email streams. This policy provides a balance between security enforcement and minimizing potential deliverability disruptions. Prerequisites for DMARC p=quarantine Implementation Before deploying a p=quarantine policy, proper configuration of SPF and DKIM is mandatory. DMARC relies on these underlying authentication mechanisms and their alignment with the sending domain. SPF (Sender Policy Framework) SPF, specified in RFC 7208 , allows domain owners to publish a list of authorized sending IP addresses in their DNS. Receiving mail servers check the SPF record to verify if an incoming email originated from an authorized server. An SPF record is a TXT record at the root of

Cycle recently introduced a separate EU-based control plane, allowing European customers to keep platform management data and telemetry within Europe. The new offering is designed to improve compliance, operational isolation, and responsiveness for European organizations. By Renato Losio

A company shifted from project- to product-thinking after their platform outgrew single-team use. The limitations that they felt with their platform were one-off deliveries, lack of product vision, and weak feedback loops. They have moved toward a self-service, API-driven, multi-tenant infrastructure with clearer ownership and better abstractions. By Ben Linders

The actor and investor is joining forces with Morgan Beller, who was previously a GP at NFX, to invest in early-stage startups.

The panelists explain the realities of running AI systems reliably at scale. While building models is solved, maintaining production databases under constant pressure is not. They discuss the emerging architectural decisions separating teams that scale gracefully from those facing catastrophic outages, and what engineering leaders must rethink today. By Simerus Mahesh, Alex Infanzon, Meryem Arik, Luca Bianchi, Renato Losio

If your Terraform plans are slow, your blast radius is too wide, or multiple teams are stepping on each other's changes, it's time to split your monolith. See The Problem with Large Terraform States for how to diagnose whether you've reached that point. This guide walks through the process of breaking a monolithic Terraform state into smaller, focused states — and how Snap CD can manage the dependencies between them so you don't have to. The approach 1. Identify natural boundaries Look at your resources and group them by lifecycle and ownership. Common boundaries: Networking — VPCs, subnets, route tables, NAT gateways. Changes rarely, underpins everything. DNS — Zones, records. Usually owned by a platform team. Compute — Kubernetes clusters, VM scale sets, container services. Changes more often, depends on networking. Application infrastructure — Databases, caches, queues, storage accounts. Owned by application teams. Monitoring — Dashboards, alerts, log sinks. Changes frequently, depends on everything but nothing depends on it. A useful test: if two resources would never be changed in the same PR by the same person, they probably belong in different states. 2. Map the dependencies Before you move anything, draw the dependency graph. Which groups produce values that other groups consume? networking dns │ ▲ ▼ │ compute ──────────►─┘ │ ▼ application │ ▼ monitoring The outputs that cross these boundaries are what you'll need to wire up after the split. Typical examples: Networking → Compute: vpc_id , private_subnet_ids Compute → DNS: load_balancer_ip Compute → Application: cluster_endpoint , cluster_ca_certificate Application → Monitoring: database_id , cache_name 3. Use terraform state mv to migrate resources Terraform's state mv command lets you move resources from one state to another without destroying and recreating them. # Initialize the destination state cd modules/networking terraform init # Move resources from the monolith to the new state terraform state mv \

At some point every growing Terraform project hits a wall. Plans that used to finish in seconds now take minutes. Applies feel risky because hundreds of resources share a single blast radius. Colleagues avoid running terraform plan because it hammers cloud APIs hard enough to trigger throttling. The state file itself becomes a liability — large, slow to lock, and one bad write away from corruption. This guide covers the symptoms of an oversized state, the band-aids teams reach for, and the structural fix that actually works. How Terraform state works under the hood Every terraform plan does two things: Refresh — for every resource in state, Terraform calls the provider's API to read the current real-world status. A state with 500 resources means 500+ API calls, often more when resources have nested data sources. Diff — compare the refreshed state against the desired configuration and produce a change set. The refresh phase is the bottleneck. It's sequential per provider (parallelism helps across providers, not within one), and every resource pays the cost whether you changed it or not. Adding ten resources to a 500-resource state doesn't make plans 2% slower — it makes the refresh 2% slower on every single plan, for every engineer, forever. Symptoms of a state that's too large Slow plans The most visible symptom. Plan time scales with resource count because every resource is refreshed on every plan, regardless of whether its configuration changed. The exact speed depends on provider — AWS resources with complex nested structures (IAM policies, security group rules) are slower to refresh than simple ones, and Azure resources that require multiple API calls per refresh are worse still. These aren't edge cases — users regularly report 2,900-resource states taking 20–25 minutes to plan and 1,600-resource states taking 8+ minutes . Even starting Terraform with a large state can take minutes before a single API call is made . There's a long-standing proposal for terraform

IndexCache: Killing the Indexer's O(NL²) Bottleneck in DeepSeek Sparse Attention Notes from my notebook on GLM-5.2 / DeepSeek Sparse Attention (DSA), reconstructed from the IndexCache paper (Bai, Dong et al., Tsinghua + Z.ai, 2026) — the mechanism behind GLM-5.2's "IndexShare." 1. Why this exists — the bottleneck nobody talks about DSA's whole pitch is: don't do full O(L²) attention, instead let a cheap lightning indexer look at all preceding tokens and pick the top-k (k=2048) that actually matter, then do real attention only on those. That drops core attention from O(L²) → O(Lk). Great — except I missed this the first time I read DSA: the indexer itself is still O(L²) . It has to score every preceding token against the query to decide who's in the top-k. So across N layers you've traded one O(L²) cost for N separate O(L²) costs — total O(NL²). At long context this indexer becomes the dominant cost, not the attention it was supposed to fix. Adding the indexer is "DSA on steroids" because it kills DSA's one real bottleneck (full attention) — but in doing so, it grows its own. The indexer is cheap per-FLOP (few heads, low-rank, FP8) but it still runs at every single layer. The fix the paper proposes isn't a smarter indexer — it's don't run it every layer at all. 2. The core insight: adjacent layers pick almost the same tokens If you measure pairwise overlap between the top-k token sets selected by each layer's indexer, adjacent layers share 70–100% of their picks. The heatmap even shows block structure — clusters of layers (e.g. layers 3–5, 17–30, etc.) that all converge on roughly the same "important" tokens. So most of the O(NL²) indexer cost is redundant computation of the same answer. This motivates IndexCache : split the N layers into two roles — F (Full) layers — run their own indexer, compute fresh top-k, cache it. S (Shared) layers — skip the indexer entirely, just reuse the nearest preceding F layer's cached top-k. The first layer is always F (has to seed the

My "serverless" database was billing me like it never slept. Neon has this great feature called scale-to-zero. Your Postgres compute suspends when it's idle, so you only pay for the queries you actually run. For a pre-revenue product, that should cost a few cents a month. Mine ran 24/7. The compute never once scaled to zero. The culprit wasn't my app logic. It was my database driver. I was using postgres-js, which holds a persistent connection open to the database. From Neon's side, an open connection looks like activity, so it never suspended. It just stayed awake and kept quietly billing me. The fix was basically one conceptual change: switch to @neondatabase/serverless, the HTTP driver. Instead of a long-lived connection, every query becomes a stateless one-shot HTTP request. The query fires, the connection closes, and the compute is free to suspend. Scale-to-zero finally worked. The lesson I keep relearning as a solo founder: "serverless" is a property of your whole stack, not a checkbox on one service. One persistent connection upstream and the whole cost model breaks.

I am committed to understand how systems actually work. I'm working on a multi-node lab to follow the complete path of a request from Python APIs to Linux processes, through Docker containers, networking and observability. The idea is simple: build a system that observes another system to understand the abstraction layers behind modern infrastructure. This project is about learning by building, experimenting and understanding what happens under the hood. Link: [ https://github.com/daniloprandi/devops-network-automation-lab ] DevOps #Linux #Python #Docker #Networking #Observability #Infrastructure

Factors like the short interval between the two powerful quakes and different types of soil led to some structures collapsing while others stayed standing.

Picture this: You just spent weeks building an awesome new feature. It's fully tested and ready to go. But when you hit "Deploy," your entire application goes down for 5 minutes, and your users are met with a blank loading screen. Not a good look. In the world of DevOps and Cloud Infrastructure, how you roll out updates matters just as much as the code itself. AWS Elastic Beanstalk gives us 5 distinct deployment policies to handle this smoothly. Let's break them down from simplest to most robust so you know exactly which one to pick for your next project. 1. All at Once (The Speed Demon) This is the simplest method. Elastic Beanstalk takes all your existing servers, shuts them down, deploys the new code, and boots them back up simultaneously. [ Old App ] ─> SHUTDOWN ALL ─> DEPLOY NEW ─> [ New App ] The Good : It’s incredibly fast. The Bad : Your app goes completely offline during the deploy. When to use it : Only in development environments where downtime doesn't matter. Never use this in production! 2. Rolling (The Line Worker) Instead of updating everything at once, Beanstalk splits your servers into batches (e.g., 2 at a time). It takes the first batch offline, updates them, brings them back online, and then moves to the next batch. Batch 1: [ Updating... ] Batch 2: [ Running Old App ] Batch 1: [ Running New App ] Batch 2: [ Updating... ] The Good : No total downtime! Your app stays online. The Bad : While a batch is updating, your overall server capacity drops. Plus, users might experience a "mixed state" where refreshing switches them between the old and new version. When to use it : Production environments that can handle a temporary dip in bandwidth. 3. Rolling with Additional Batch (The Safe Substitution) To fix the capacity problem of standard rolling, this policy launches a brand new batch of instances first. Once those new servers are healthy and running the updated code, Beanstalk starts rolling the update through the old servers. [Old Servers: 100% Capa

And by viral I mean from $0 to $31. Umami told me Clew Directive got 14 visits last month. AWS told me I owed $31 for it. That works out to $2.21 a visitor, which would make it the most expensive free learning-path tool in California. Spoiler alert: 14 visitors, $31, and not a single one of them was the reason. Something was off. Here is how Amazon Q, Claude, and a few hours of reading my own code untangled it. The app turned out to be innocent. What Clew Directive is, quickly A free, stateless tool that builds you a personalized AI learning-path PDF. You take a 60-second Vibe Check, four questions about your goals and how you learn, and it maps you to free, verified resources and hands you a briefing. No accounts, no database, no paywall, nothing stored about you. It runs on Amazon Nova, which is why it costs close to nothing to operate, which is also why a $31 bill made no sense. The name is the Theseus kind of clew. A ball of thread to find your way out of the maze. Less hype, more direction. Live at clewdirective.com . The number that didn't add up Twelve visitors, 14 visits, 93% bounce, average session about a minute. Referrers from Bing, Google, Yahoo, GitHub. Visitors from the US, India, Netherlands, Egypt, Ethiopia, Singapore. Mostly crawlers stopping by to say hello. A few curious humans and a parade of bots is not a $31 month. So either every visit was doing something enormous, or the bill was never about visits at all. The dashboard lied, politely. An Amazon Q Story My cost tracker said Clew Directive was running on Claude Sonnet. Sonnet is the expensive one. Case closed, right? I opened the repo. Clew Directive does not run Sonnet. The Navigator agent runs Amazon Nova 2 Lite. Scout and Curator run Nova Micro. The IAM policy is scoped to Nova ARNs only, so a Sonnet call from these functions would come back AccessDenied. The app physically cannot bill Sonnet. The math agreed. A full learning-path generation on Nova costs about two-tenths of a cent. Fourtee

devtools #infrastructureascode #cdk #aws Index TL;DR Major Features Bedrock AgentCore — From Alpha to Stable Fn::GetStackOutput & Weak Cross-Stack References Validations Framework Performance Improvements CloudWatch PromQL Alarms CLI Improvements New L2 Constructs Service Enhancements Community Highlights Community Content & Resources How Can You Be Involved Hey CDK community! Here's an update covering everything that shipped in April and May 2026. TL;DR Bedrock AgentCore graduated to stable — production-ready AI agent infrastructure with semver guarantees. Cross-region references got a major upgrade with native Fn::GetStackOutput support and weak cross-stack references. The new Validations framework replaces policyValidationBeta1 with a richer plugin system. And file fingerprinting is ~33% faster with persistent asset caching. These features are available in aws-cdk-lib v2.247.0 through v2.257.0 and aws-cdk CLI v2.1116.0 through v2.1125.0. Full changelogs on GitHub Releases ( Library | CLI ). Major Features Bedrock AgentCore — From Alpha to Stable The @aws-cdk/aws-bedrock-agentcore-alpha module has graduated to aws-cdk-lib/aws-bedrockagentcore — stable APIs, semver guarantees, production-ready. If you've been building AI agents with Bedrock but held off on CDK because of the alpha label, it's time to upgrade. ( #37876 ) AgentCore provides the core infrastructure for building AI agents: runtimes, gateways, identity management, observability, and online evaluation. The Policy submodule remains in alpha as it continues to evolve rapidly. ┌─────────────────────────────────────────────────────┐ │ Bedrock AgentCore (Stable) │ ├─────────────────────────────────────────────────────┤ │ │ │ ┌──────────┐ ┌──────────┐ ┌──────────────────┐ │ │ │ Runtime │ │ Gateway │ │ Identity │ │ │ │ (L2) │ │ (L2) │ │ (L2) │ │ │ └────┬─────┘ └────┬─────┘ └────────┬─────────┘ │ │ │ │ │ │ │ ▼ ▼ ▼ │ │ ┌──────────┐ ┌──────────┐ ┌──────────────────┐ │ │ │Observa- │ │Online │ │ Policy Engine │ │ │

Our infrastructure "documentation" was a Google Sheet. Anyone on the team could edit it. Nobody...

AWS released Blocks in public preview, an open-source TypeScript framework where each Block bundles application code, local mocks, and AWS infrastructure. Designed for AI agents to write correct backends from the start, it runs locally without an AWS account and deploys the same code to Lambda, DynamoDB, Aurora, and Bedrock with zero changes. By Steef-Jan Wiggers

GitOps policy drift is what happens when a control plane keeps a policy perfectly reconciled long after the reason for that policy has stopped being true. Every commit is applied. Every pull request is merged cleanly. Every dashboard reads green. And the rule being enforced no longer reflects anything anyone would choose to enforce today — it just hasn't been told to stop. That gap is the subject of this post. Not configuration drift — the thing GitOps was built to kill — but a second, quieter failure mode that lives one layer above it: the policy is right by every technical measure and wrong by every practical one, and nothing in the reconciliation loop is capable of telling the difference. The Promise GitOps Actually Kept GitOps earned its place in the infrastructure as code architecture stack by solving a real and expensive problem: state drift. Before declarative reconciliation, infrastructure diverged from its source of truth constantly — a console change here, an emergency hotfix there, a manual override nobody logged. The git repository said one thing. Production said another. Reconciling the two was a forensic exercise. GitOps closed that gap with a simple, durable mechanism: a controller that continuously compares declared state to actual state and corrects the difference without waiting for a human to notice. That's not a small win. It's the reason platform teams can run infrastructure at a scale that would have been operationally unmanageable a decade ago, and it's why GitOps controllers sit at the center of nearly every modern infrastructure as code architecture built since. This post isn't an argument against that mechanism. It's an argument that the mechanism's success created a blind spot nobody designed for. What GitOps Never Promised to Solve Here's the boundary GitOps was never built to cross: reconciliation proves that declared state and actual state match. It says nothing about whether the declared state should still exist in its current form. A

You already have Playwright tests. They run in CI on every pull request, they assert that login works and checkout completes, and then they stop — because CI only runs them against a branch, at merge time. The moment the code is in production, those tests go silent. A third-party script breaks checkout at 3 AM and your perfectly good test suite says nothing, because nothing triggered it. Playwright monitoring closes that gap: you take the same browser tests and run them on a schedule against production, turning your end-to-end suite into a synthetic monitoring system that watches real user journeys continuously. Prerequisites Node.js 18+ and an existing project ( npm install -D @playwright/test , then npx playwright install chromium ). A deployed production (or staging) URL to run checks against. A dedicated synthetic test account — never a real customer's credentials. A secret store for that account's credentials (GitHub Actions secrets, or your platform's equivalent). Never hard-code them. Step 1 — Write a check that asserts on what the user sees A monitor-grade check is not "did the page load." It is "could a user complete the thing they came to do." Assert on the outcome, with a generous timeout for real-world latency: import { test , expect } from " @playwright/test " ; test ( " checkout reaches confirmation " , async ({ page }) => { await page . goto ( " https://shop.example.com " ); await page . getByRole ( " button " , { name : " Add to cart " }). click (); await page . getByRole ( " link " , { name : " Checkout " }). click (); await page . getByLabel ( " Email " ). fill ( process . env . SYNTHETIC_EMAIL ! ); await page . getByLabel ( " Card number " ). fill ( " 4242424242424242 " ); await page . getByRole ( " button " , { name : " Pay now " }). click (); // The assertion a 200 OK can never make for you: await expect ( page . getByText ( " Order confirmed " )). toBeVisible ({ timeout : 15000 , }); }); Credentials come from process.env , not the source. The t

One of the most common system design interview questions is: "How would you scale a web application from 100 users to 100 million users?" The answer is rarely a single technology. Instead, systems evolve through multiple stages, with each stage solving a specific bottleneck. This article walks through the typical evolution of a scalable system and explains why , how , and when each component is introduced. 1. Single Server Why Start Here? Every application starts simple. In the beginning: Traffic is low Development speed matters more than scalability Infrastructure costs should be minimal What Is It? A single machine handles everything: Frontend Backend Database Users | v Single Server ├── Application └── Database How Does It Work? User sends request. Application processes request. Database stores and retrieves data. Response is returned. Everything happens on one machine. Problem As traffic grows: CPU becomes overloaded Memory becomes insufficient Database competes with application for resources A single server becomes a bottleneck. Interview One-Liner A single server architecture is simple and cost-effective but becomes a bottleneck as traffic and resource usage increase. 2. Application and Database Separation Why Do We Need It? The application and database have different workloads. Application Server: Uses CPU Handles business logic Database Server: Uses memory and storage Handles queries Keeping them together causes resource contention. How Does It Work? Move the database to a separate machine. Users | v Application Server | v Database Server Benefits Independent scaling Better resource utilization Improved performance Example Suppose an e-commerce website receives thousands of requests. The application handles: Authentication Order processing API responses The database handles: Product data Orders User information Separating them prevents one workload from affecting the other. Interview One-Liner Separating the application and database allows each layer to scal