# After The Retrospective

Published articles for After The Retrospective.

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## How to test application resiliency by simulating the Cloudflare December 2025 outage

DevFeed: [How to test application resiliency by simulating the Cloudflare December 2025 outage](<https://devfeed.tech/articles/how-to-test-application-resiliency-by-simulating-the-cloudflare-december-2025-outage-11636.md>)

Original publisher: [Read original article](<https://www.gremlin.com/blog/how-to-test-application-resiliency-by-simulating-the-cloudflare-december-2025-outage>)

Author: Gavin Cahill

Published: 2025-12-19T00:00:00Z

Content type: tutorial

Language: en

Sources: [Gremlin Blog](<https://devfeed.tech/sources/gremlin-blog.md>)

Topics: [Failure Flags](<https://devfeed.tech/topics/failure-flags.md>), [Resilience](<https://devfeed.tech/topics/resilience.md>), [incident](<https://devfeed.tech/topics/incident.md>), [Chaos Engineering](<https://devfeed.tech/topics/chaos-engineering.md>), [SDKs](<https://devfeed.tech/topics/sdks.md>), [JavaScript](<https://devfeed.tech/topics/javascript.md>), [Node.js](<https://devfeed.tech/topics/node-js.md>), [Python](<https://devfeed.tech/topics/python.md>), [Kubernetes](<https://devfeed.tech/topics/kubernetes.md>), [AWS Lambda](<https://devfeed.tech/topics/aws-lambda.md>), [Azure](<https://devfeed.tech/topics/azure.md>)

Tags: [2025](<https://devfeed.tech/tags/2025.md>), [after-the-retrospective](<https://devfeed.tech/tags/after-the-retrospective.md>), [applications](<https://devfeed.tech/tags/applications.md>), [aws](<https://devfeed.tech/tags/aws.md>), [aws-lambda](<https://devfeed.tech/tags/aws-lambda.md>), [azure](<https://devfeed.tech/tags/azure.md>), [c-sharp](<https://devfeed.tech/tags/c-sharp.md>), [cloud](<https://devfeed.tech/tags/cloud.md>), [cloudflare](<https://devfeed.tech/tags/cloudflare.md>), [code](<https://devfeed.tech/tags/code.md>), [failure-flags](<https://devfeed.tech/tags/failure-flags.md>), [gremlin](<https://devfeed.tech/tags/gremlin.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [http](<https://devfeed.tech/tags/http.md>), [incident](<https://devfeed.tech/tags/incident.md>), [internet-traffic](<https://devfeed.tech/tags/internet-traffic.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [kubernetes](<https://devfeed.tech/tags/kubernetes.md>), [node-js](<https://devfeed.tech/tags/node-js.md>), [outage](<https://devfeed.tech/tags/outage.md>), [python](<https://devfeed.tech/tags/python.md>)

### AI overview

This tutorial explains how to use Gremlin Failure Flags to simulate HTTP 500 errors associated with the December 2025 Cloudflare outage. It describes application-layer fault injection, the distinction from network-layer experiments, and supported deployment environments and SDK languages.

### Source excerpt

Use Gremlin Failure Flags to safely simulate 500 error codes and test resiliency to outages, like the December 5th Cloudflare incident.

## Reliability lessons from the 2025 Cloudflare outage

DevFeed: [Reliability lessons from the 2025 Cloudflare outage](<https://devfeed.tech/articles/reliability-lessons-from-the-2025-cloudflare-outage-11697.md>)

Original publisher: [Read original article](<https://www.gremlin.com/blog/reliability-lessons-from-the-2025-cloudflare-outage>)

Author: Andre Newman

Published: 2025-11-20T00:00:00Z

Content type: article

Language: en

Sources: [Gremlin Blog](<https://devfeed.tech/sources/gremlin-blog.md>)

Topics: [Cloudflare](<https://devfeed.tech/topics/cloudflare.md>), [Bot Management](<https://devfeed.tech/topics/bot-management.md>), [configuration](<https://devfeed.tech/topics/configuration.md>), [Chaos Engineering](<https://devfeed.tech/topics/chaos-engineering.md>), [Post Mortem](<https://devfeed.tech/topics/post-mortem.md>), [Network](<https://devfeed.tech/topics/network.md>), [Workers](<https://devfeed.tech/topics/workers.md>)

Tags: [2025](<https://devfeed.tech/tags/2025.md>), [after-the-retrospective](<https://devfeed.tech/tags/after-the-retrospective.md>), [bot-management](<https://devfeed.tech/tags/bot-management.md>), [chaos-engineering](<https://devfeed.tech/tags/chaos-engineering.md>), [cloudflare](<https://devfeed.tech/tags/cloudflare.md>), [configuration](<https://devfeed.tech/tags/configuration.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [http](<https://devfeed.tech/tags/http.md>), [internet](<https://devfeed.tech/tags/internet.md>), [management](<https://devfeed.tech/tags/management.md>), [outage](<https://devfeed.tech/tags/outage.md>), [outages](<https://devfeed.tech/tags/outages.md>), [post-mortem](<https://devfeed.tech/tags/post-mortem.md>), [workers](<https://devfeed.tech/tags/workers.md>)

### AI overview

The article examines the November 2025 Cloudflare outage, explaining how an oversized Bot Management configuration caused HTTP 5XX errors and cascading failures across dependent services. It highlights configuration propagation, service dependencies, and chaos engineering as reliability considerations.

### Source excerpt

In November 2025, a misconfigured Cloudflare service led to a partial outage. Learn what happened, and what you can do to reduce the impact of similar outages.

## Reliability lessons from the 2025 Microsoft Azure Front Door outage

DevFeed: [Reliability lessons from the 2025 Microsoft Azure Front Door outage](<https://devfeed.tech/articles/reliability-lessons-from-the-2025-microsoft-azure-front-door-outage-11699.md>)

Original publisher: [Read original article](<https://www.gremlin.com/blog/reliability-lessons-from-the-2025-microsoft-azure-front-door-outage>)

Author: Gavin Cahill

Published: 2025-11-17T00:00:00Z

Content type: opinion

Language: en

Sources: [Gremlin Blog](<https://devfeed.tech/sources/gremlin-blog.md>)

Topics: [Azure](<https://devfeed.tech/topics/azure.md>), [Microsoft](<https://devfeed.tech/topics/microsoft.md>), [Cloud](<https://devfeed.tech/topics/cloud.md>), [cloud-infrastructure](<https://devfeed.tech/topics/cloud-infrastructure.md>)

Tags: [2025](<https://devfeed.tech/tags/2025.md>), [after-the-retrospective](<https://devfeed.tech/tags/after-the-retrospective.md>), [azure](<https://devfeed.tech/tags/azure.md>), [backup](<https://devfeed.tech/tags/backup.md>), [best-practices](<https://devfeed.tech/tags/best-practices.md>), [cloud](<https://devfeed.tech/tags/cloud.md>), [infrastructure](<https://devfeed.tech/tags/infrastructure.md>), [microsoft](<https://devfeed.tech/tags/microsoft.md>), [outage](<https://devfeed.tech/tags/outage.md>), [outages](<https://devfeed.tech/tags/outages.md>), [recovery](<https://devfeed.tech/tags/recovery.md>), [uptime](<https://devfeed.tech/tags/uptime.md>), [xbox](<https://devfeed.tech/tags/xbox.md>)

### AI overview

This article examines reliability lessons from the October 2025 global outage affecting Microsoft Azure Front Door, Azure Content Delivery Network, and related Microsoft services. It emphasizes customer responsibility for uptime, redundancy, tested failover, and active-active infrastructure.

### Source excerpt

In October 2025, Microsoft Azure Front Door and Content Delivery Network suffered a global outage. Find out what your team can do to minimize the impact of similar outages in the future.

## How to be prepared for cloud provider outages

DevFeed: [How to be prepared for cloud provider outages](<https://devfeed.tech/articles/how-to-be-prepared-for-cloud-provider-outages-11605.md>)

Original publisher: [Read original article](<https://www.gremlin.com/blog/how-to-be-prepared-for-cloud-provider-outages>)

Author: Gavin Cahill

Published: 2025-06-13T00:00:00Z

Content type: article

Language: en

Sources: [Gremlin Blog](<https://devfeed.tech/sources/gremlin-blog.md>)

Topics: [Cloud](<https://devfeed.tech/topics/cloud.md>), [Resilience](<https://devfeed.tech/topics/resilience.md>), [systems](<https://devfeed.tech/topics/systems.md>), [Cloudflare](<https://devfeed.tech/topics/cloudflare.md>), [Database](<https://devfeed.tech/topics/database.md>), [Caching](<https://devfeed.tech/topics/caching.md>)

Tags: [after-the-retrospective](<https://devfeed.tech/tags/after-the-retrospective.md>), [best-practices](<https://devfeed.tech/tags/best-practices.md>), [cache](<https://devfeed.tech/tags/cache.md>), [cloud](<https://devfeed.tech/tags/cloud.md>), [cloudflare](<https://devfeed.tech/tags/cloudflare.md>), [outages](<https://devfeed.tech/tags/outages.md>), [resilience](<https://devfeed.tech/tags/resilience.md>), [systems](<https://devfeed.tech/tags/systems.md>), [testing](<https://devfeed.tech/tags/testing.md>)

### AI overview

This article explains how hidden dependencies can amplify cloud provider outages, using a GCP outage and its effects on Cloudflare as examples. It recommends resilience testing, including controlled failure simulations such as Blackhole experiments, to verify failover behavior and graceful degradation before a real outage occurs.

### Source excerpt

Check out these testing best practices teams should follow to minimize the impact of cloud provider outages so they don't catch you by surprise.