61 posts
Cloudflare Radar tracked Internet disruptions driven by natural disasters, government-mandated shutdowns, and DNSSEC key rollovers over the last quarter. This blog post analyzes traffic telemetry to explain how these events impacted global connectivity.
Over the past few years, we’ve been on a journey to modernise how we run Amazon Elastic Compute Cloud (EC2) instances at Slack. In our first post, Advancing Our Chef Infrastructure, we shared how we moved from a single Chef stack to a resilient, multi-stack setup with versioned cookbook deployments and safer promotion workflows. This…
My husband runs a pop-up bakery called Molta, and he needed a website. Nothing fancy: who he is, what he bakes, where to find us, etc. For a site this small, the obvious move is to pay for a Squarespace site (or something similar), click a few templates together, and be done in an afternoon. […] The post How to…
Rails gave web developers a durable caching model. Cache the outer fragment. Reuse the inner fragments that did not change. The Rails caching guide calls this Russian doll caching. You Can Use Russian Doll Caching at the Edge. The same idea now applies outside the template. The dolls can span the browser cache, CloudFront, the […] The post Russian Doll…
By Alvin Bao , Alex Petrov , Jennifer Lai , Aidan Sherr , and Samartha Chandrashekar As a part of the journey to transition Netflix’s compute infrastructure to be more Kubernetes-native, we have leaned into incorporating components from the Kubernetes ecosystem into our container platform Titus . One example of this is our use of Kueue , a cloud-native job…
REX FinOps : en ouvrant AWS Cost Explorer sur un data lake à 6 500 $/mois, trois anomalies apparaissent. AWS KMS à 4 000 $/mois, des licences fantômes pour des développeurs partis, 10 pipelines CI/CD redondantes. Optimisation des coûts cloud : 100 000 $ d'économies annuelles. Sans outil, sans migration. Juste de la curiosité. Checklist incluse.
Photo by Corinne Kutz on Unsplash Before we knew better Our orchestration system started as a simple internal solution to manage event pipelines and trigger downstream jobs. Over time, as more workflows and dependencies were added, it gradually evolved into a tightly coupled monolithic scheduler that became increasingly difficult to understand and maintain. Understanding how a workflow executed often meant…
In early 2023, Slack faced a foundational challenge: serving Large Language Models (LLMs) at enterprise scale with the security, reliability, and performance our customers expect. Over three years, we evolved from basic infrastructure to orchestrating a sophisticated multi-cloud architecture. We didn’t just want shiny new models; we needed a system resilient to regional outages and…
On a recent software development project that already planned to use AWS, we used AWS Cognito for authentication. Cognito is Amazon’s managed identity platform for web and mobile apps, offering features like MFA, password reset flows, and sign-in. On paper, it’s a strong fit for projects already using AWS. In practice, the rough edges cost […] The post 3 AWS…
How a seemingly simple AWS API call can silently slow down your CI/CD pipelines Review/co-researcher: Gonzalo Ulla The Mystery It started with a line in one of our team’s CI/CD logs that nobody expected: module.project.module.user_buckets.module.s3_bucket.data.aws_organizations_organization.current: Still reading… [15m10s elapsed] 15 minutes and 10 seconds — just to read organization data. A value that should return in milliseconds was holding up…
Excerpt By 2024, Slack’s data platform had accumulated 700+ SSH-based operators orchestrating critical data pipelines. We’re talking daily search indexing that processed terabytes of data, analytics jobs powering business intelligence, the whole shebang. Every single one of these jobs required direct SSH access to production AWS Elastic MapReduce (EMR) clusters. We had a massive security…
How to write reusable middleware for Rust Lambda functions using tower, the generic middleware engine that already underpins the AWS Lambda Rust runtime. Includes a complete DynamoDB-backed IP rate limiter with SAM deployment.
This post was originally published internally on May 9, 2025 and has been reworked for a public audience. Authors: Ioannis Androulidakis , Mohammed Gaafar Intro The Database Engineering team at Booking.com is constantly looking for ways to improve database reliability and support scaling our business. In 2025 we completed a major milestone in our effort to modernize our infrastructure: we…
Learn how to debug silent failures in AWS API Gateway HTTP when your OIDC provider doesn't implement the .well-known/openid-configuration endpoint. Enable FailOnWarnings to catch these issues before they break your production deployment.
At the recent AWS re:Invent, Docker focused on a very real developer problem: how to run AI agents locally without giving them access to your machine, credentials, or filesystem. With AWS introducing Kiro, Docker demonstrated how Docker Sandboxes and MCP Toolkit allow developers to run agents inside isolated containers, keeping host environments and secrets out...
For modern enterprises building cloud-native applications, success hinges on achieving maximum development velocity at every scale. Infrastructure as a Service (IaaS) providers like AWS provide hundreds of services with the unmatched reliability and scale needed for enterprise infrastructure, but they can require significant effort and expertise for organizations to be effective and efficient. To achieve […] The post PaaS +…
Last year, I wrote a blog post titled Advancing Our Chef Infrastructure, where we explored the evolution of our Chef infrastructure over the years. We talked about the shift from a single Chef stack to a multi-stack model, and the challenges that came with it – from updating how we handle cookbook uploads to navigating…
Supporting developers to debug and resolve issues with datastores in the Self-Service ecosystem. Welcome to the third blog post of our Self-Service Datastore series, where we share our journey towards creating a more efficient and reliable way to manage datastores at Zendesk. Previous blog posts: Unlocking Efficiency: A New Era for Datastore Provisioning Simplifying Datastore Provisioning with Kubernetes Operators We…
Okay, yes, the title is a bit clickbaity — but stick with me because this is a real story about SRE work, cost optimization, Golang, and open source. An Introduction and Context I apologize for the clickbait title, but I promise this is a real story that gives you a glimpse into what SREs do daily at Booking.com. It’s based…
Discover the journey behind FullStack Bulletin, a weekly newsletter for full-stack developers with 404 curated issues over 8 years. Learn about its origins, technical implementation, and future plans.
Introduction Welcome to the second blog post of our Self-Service Datastore series, where we share our journey towards creating a more efficient and reliable way to manage datastores at Zendesk. In today’s dynamic application development landscape, the ability to swiftly provision datastores is crucial for maintaining agility and delivering exceptional user experiences. Provisioning encompasses all steps involved in requesting a…
At Slack, we manage tens of thousands of EC2 instances that host a variety of services, including our Vitess databases, Kubernetes workers, and various components of the Slack application. The majority of these instances run on some version of Ubuntu, while a portion operates on Amazon Linux. With such a vast infrastructure, the critical question…
Slack Data Engineering recently underwent data workload migration from AWS EMR 5 (Spark 2/Hive 2 processing engine) to EMR 6 (Spark 3 processing engine). In this blog, we will share our migration journey, challenges, and the performance gains we observed in the process. This blog aims to assist Data Engineers, Data Infrastructure Engineers, and Product…
One of our most important goals at Heroku is to be boring. Don’t get us wrong, we certainly hope that you’re excited about the Heroku developer experience — as heavy users of Heroku ourselves, we certainly are! But, even more so, we hope that you don’t have to spend all that much time thinking about […] The post Evolving the…
Bazaarvoice notification system stands as a testament to cutting-edge technology, designed to seamlessly dispatch transactional email messages (post-interaction email or PIE) on behalf of our clients. The heartbeat of our system lies in the constant influx of new content, driven by active content solicitations. Equipped with an array of tools, including email message styling, default […]
At Slack, we’ve long been conservative technologists. In other words, when we invest in leveraging a new category of infrastructure, we do it rigorously. We’ve done this since we debuted machine learning-powered features in 2016, and we’ve developed a robust process and skilled team in the space. Despite that, over the past year we’ve been…
We are heavy users of Amazon Compute Compute Cloud (EC2) at Slack — we run approximately 60,000 EC2 instances across 17 AWS regions while operating hundreds of AWS accounts. A multitude of teams own and manage our various instances. The Instance Metadata Service (IMDS) is an on-instance component that can be used to gain an…
When building a custom API Gateway authorizer, mysterious 500 errors can happen. This post shows how to enable CloudWatch logging for API Gateway to inspect the logs and debug problems.
In May 2023, we announced our limited release of two new Heroku Private Spaces regions: India (Mumbai) and Canada (Montreal). This month, we’re announcing the full general availability of those two regions, along with new Heroku Private Spaces regions for the United Kingdom (London) and Singapore. This expansion enables customers to maintain greater control over […] The post Heroku Private…
Heroku is excited to announce the addition of a third availability zone (AZ) for our Private Spaces product offering. Three availability zones make Private Space apps more resilient to outages. We’ve prioritized this improvement as part of our focus on mission-critical features to make the Heroku Platform even more reliable. The changeover to three availability […] The post Heroku Adds…
(cover image from ThisisEngineering RAEng) Let’s face it: software is easier to write than maintain. This is why we, as software engineers, prefer to just “rip it out and start over” instead of trying to understand what another developer (or our past self) was thinking. We seem to have collectively forgotten that “programs must be […]
Authored by: Rojan Rijal, Tinder Security Labs | Johnny Nipper, Sr. Director | Tanner Emek, Sr Engineering Manager Summary In 2021, GitHub released support for OpenID Connect (OIDC) for GitHub Actions (GHA), allowing developers to securely interact with their infrastructure resources in Amazon Web Services (AWS), and other major cloud service providers. The OIDC support allows GHA jobs to retrieve…
User Journey is an integral part of any product, and a well defined workflow encapsulates the user experience and becomes nearly imperceptible to the user. CRED employs AWS Step Functions to offer seamless product experience. Example Onboarding Steps What are AWS Step Functions? AWS Step Functions is a low-code, server-less orchestration service that developers can use to build distributed applications,…
Slack launched GovSlack in July 2022. With GovSlack, government agencies, and those they work with, can enable their teams to seamlessly collaborate in their digital headquarters, while keeping security and compliance at the forefront. Using GovSlack includes the following benefits: Supports key government security standards, such as FedRAMP High, DoD IL4, and ITAR Runs in…
At Slack, we use Terraform for managing our Infrastructure, which runs on AWS, DigitalOcean, NS1, and GCP. Even though most of our infrastructure is running on AWS, we have chosen to use Terraform as opposed to using an AWS-native service such as CloudFormation so that we can use a single tool across all of our…
The AWS Solutions Architect Professional certification is one of the toughest IT certifications. This post shares preparation tips, exam strategies, study resources, and sample questions to help you succeed.
BBC Online — A year with serverless Its been a little over a year since I published my last two blog posts, in which I outlined the process we went through to choose the technology for BBC online and the steps we took to optimise serverless for our use. Recently my colleague Graeme has published a blog post on the…
This article was originally authored by Srinath Ananthakrishnan, an engineer on the Heroku Runtime Networking Team Summary This following story outlines a recent issue we saw with migrating one of our internal systems over to a new EC2 substrate and in the process breaking one of our customer’s use cases. We also outline how we […] The post The Adventures…
This post explains how to conditionally create resources in AWS CDK using CfnCondition. It provides a practical example of creating an S3 bucket based on an SSM parameter value. The post covers defining a condition, attaching it to a low-level CDK construct, and importing the conditionally created resource.
Pinion — The Load Framework Part-2 This post is the 2nd part of the “Pinion — The Load Framework” series. In case you have not read the 1st post, you can read it here . In this post, we are going to cover the following topics. How does Pinion use Delta Lake for SCD operations? Small file problem with Delta…
About a year ago, I wrote a blog post called Building the Next Evolution of Cloud Networks at Slack. In it, we discussed how Slack’s AWS infrastructure has evolved over the years and the pain points that drove us to spin up a brand-new network architecture redesign project called Whitecastle. If you have not had…
This post explains how to use CDK to provision Ubuntu EC2 instances on AWS. It covers finding the right AMI, adding security groups, using init scripts, installing AWS utilities, and more.
The boto3 Python SDK allows intercepting requests before they are sent to AWS through an event handler system. This article shows how to use it to gzip the payload of PutMetricData requests sent to CloudWatch.
Security is always top of mind for Heroku customers; COVID-19 has further increased the urgency for enterprises and developers to deliver more mission-critical applications with sensitive and regulated data. Given the needs of our customers, including those in regulated industries like Health & Life Sciences and Financial Services, we are thrilled to announce that Heroku […] The post Bring Your…
Today, we’re thrilled to announce four new trusted data integrations that allow data to flow seamlessly and securely between Heroku and external resources in public clouds and private data centers: Heroku Postgres via mutual TLS Heroku Postgres via PrivateLink Apache Kafka on Heroku via PrivateLink Heroku Redis via PrivateLink These integrations expand Heroku’s security and […] The post Announcing Heroku…
At Clever, we lock down code access to customer data using AWS IAM roles with session policies. In Clever’s microservice AWS architecture, each service has a unique IAM role with access to the AWS resources it needs: S3 buckets, DynamoDB tables, and so on. Our services are multi-tenant and customer data is separated via logical […] The post Using IAM…
Today, we’re thrilled to announce Heroku Postgres via PrivateLink, a new integration that enables customers to seamlessly and securely connect Heroku Postgres databases in Private Spaces to resources in one or more Amazon VPCs. Heroku Postgres via PrivateLink connections are secure and stable by default because traffic to and from Heroku Postgres stays on the […] The post Heroku Postgres…
Building a SaaS product, a system to handle sensor data from an internet-connected thermostat or car, or an e-commerce store often requires handling a large stream of product usage data, or events. Managing event streams lets you view, in near real-time, how users are interacting with your SaaS app or the products on your e-commerce […] The post Manage Real-time…
The AWS Solutions Architect Associate exam covers a wide range of AWS services. This post shares helpful notes and tips for studying key concepts like EC2, S3, VPC, DynamoDB, and more. It provides advice on the exam mindset and lists official and unofficial preparation resources. The notes summarize important details around provisioned throughput, instance types, database replication and more that…
Today we’re excited to announce Site-to-Site Virtual Private Network (VPN) support for Heroku Private Spaces. Heroku customers can now establish secure, site-to-site IPsec connections between Private Spaces on Heroku and their offices, datacenters and deployments on non-AWS clouds. VPN is a powerful, proven and widely-adopted technology for securely combining multiple networks (or adding individual hosts […] The post VPN Support…
Today we’re announcing a powerful new network control for apps running in Heroku Private Spaces: Internal Routing. Apps with Internal Routing work exactly the same as other Heroku apps, except the web process type is published to an endpoint that’s routable only within the Private Space and on VPC and VPN peered networks (see the […] The post Internal Routing…
Rails 5.2 was just released last month with a major new feature: Active Storage. Active Storage provides file uploads and attachments for Active Record models with a variety of backing services (like AWS S3). While libraries like Paperclip exist to do similar work, this is the first time that such a feature has been shipped […] The post Rails 5.2…
The AWS CLI s3 cp command supports streaming content to and from S3 using stdin/stdout with the - argument. This enables powerful pipelines without intermediary files.
At Clever, one of our tenets is “Always a Student”, and in that spirit of learning we wanted to share the changes we made to fix memory allocation issues in AWS Elastic Container Service related to swappiness. Swappiness is a Linux Kernel setting that specifies how likely it is for a page in memory to be […] The post Swappiness…
This article explores the history of cloud computing from bare metal servers to serverless, explaining key innovations like IaaS, PaaS, containers and FaaS along the way.
This post explains how to use Let's Encrypt and Certbot to automatically generate and renew SSL certificates for OpenVPN. It provides a complete Terraform setup as a practical example.
Cloudformation is a powerful tool for building large, coordinated clusters of AWS resources. It has a sophisticated API, capable of supporting many different enterprise use-cases and scaling to thousands of stacks and resources. However, there is a downside: the JSON interface for specifying a stack can be cumbersome to manipulate, especially as your organization grows […]
Greetings all! In the world of SaaS, wiser men than I have referred to Operations as the “Secret Sauce” that distinguishes you from your competition. As manager of one of our DevOps teams, I wanted to talk to you about how Bazaarvoice uses the cloud and how we engineer our systems for maximum reliability. You […]
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