Free ebook: Building Hybrid Applications in the Cloud on Windows Azure

The Microsoft Patterns and Practices team released a new version of the ‘Building Hybrid Application in the Cloud on Windows Azure’ ebook.

“This book is the third volume in a series on Windows Azure. Volume 1, Moving Applications to the Cloud on Windows Azure, provides an introduction to Windows Azure, discusses the cost model and application life cycle management for cloud-based applications, and describes how to migrate an existing ASP.NET application to the cloud. Volume 2, Developing Applications for the Cloud on Windows Azure, discusses the design considerations and implementation details of applications that are designed from the beginning to run in the cloud. It also extends many of the areas covered in Volume 1 to provide information about more advanced techniques that you can apply in Windows Azure applications.

This third volume in the series demonstrates how you can use the powerful infrastructure services that are part of Windows Azure to simplify development; integrate the component parts of a hybrid application across the cloud, on-premises, and third-party boundaries; and maximize security, performance scalability, and availability.

This guide is intended for architects, developers, and information technology (IT) professionals who design, build, or operate applications and services that run on or interact with the cloud. Although applications do not need to be based on the Microsoft® Windows® operating system to operate in Windows Azure, this book is written for people who work with Windows-based systems. You should be familiar with the Microsoft .NET Framework, the Microsoft Visual Studio® development system, ASP.NET MVC, and the Microsoft Visual C#® development language.”

Perfect holiday lecture Glimlach .

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME ...

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...

A complex system designed from scratch never works

A few years ago, I worked as an architect on a big mainframe rewrite. I still count it as one of my failures. Not because the technology was wrong, but because I couldn't convince the management team to simplify the approach. Years later, the organization is still struggling to get the new system up and running. I left the project at the time, because I couldn't put my name behind an approach that would take very long and cost a lot of money without a working system to show for it along the way. Gall’s Law That memory keeps coming back to me, because it's a textbook case of Gall's Law playing out in real life. Gall's Law , from John Gall's Systemantics , states it plainly: A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works, and it cannot be patched to make it work. You have to start over with a simple system that works. What does that mean in practice,...

The art of simplicity

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