Finding the boundaries of your system and decompose it into multiple services sounds easy, but it certainly isn’t.
If you are interested in this topic, check out the blog series by Vadim Samokhin:
Remark: After writing this post, I noticed that Vadim created a blog post linking to the series above and included also some other related posts.
One of the ways you can save some money using Azure is by using spot node pools for your Azure Kubernetes Service cluster.
Using a spot node pool allows you to take advantage of unused Azure capacity at a significant cost savings. At any point in time when Azure needs the capacity back, the Azure infrastructure will evict spot nodes. Therefore, Spot nodes are great for workloads that can handle interruptions like batch processing jobs, dev/test environments, large compute workloads, and more.
Remark: A spot node pool can't be the cluster's default node pool. A spot node pool can only be used for a secondary pool.
Pricing for spot instances is variable, based on region and SKU. For more information, see pricing for Linux and Windows. You do have the option to set a max price. In case the price is exceeded the spot node is evicted from your cluster.
A spot node pool has the label kubernetes.azure.com/scalesetpriority:spot and the taint kubernetes.azure.com/scalesetpriority=spot:NoSchedule. We use this information to add a toleration in our deployment.yaml:
In case you have multiple spot node pools, you can use a nodeselector to select a specific pool:
I’ve been using Chocolatey for a long time as an easy way to get my Windows machine configured with all the software I need. With the release of version 1.1 of the Windows Package Manager(WinGet) I thought it was a good time to give it a try.
Chances are high that WinGet is already available on your machine. Open a terminal and type winget. If it is available you should see something like this:
If not, the Windows Package Manager is distributed with the App Installer from the Microsoft Store. You can also download and install the Windows Package Manager from GitHub, or just directly install the latest available released version.
The list of available packages is quite large(more than 2,600 packages in the Windows Package Manager app repository). Just run winget search <SomePackage> to see if the package you are looking for has available there.
For example let’s search for my favorite git client GitKraken:
PS C:\Users\bawu> winget search gitkraken
Naam Id Versie Bron
------------------------------------------
GitKraken Axosoft.GitKraken 8.1.0 winget
For packages inside the Microsoft store you don’t get a readable id but a hash value instead:
PS C:\Users\bawu> winget search git
Name Id Version Source
-------------------------------------------------------------------------------------------------------------------
Learn Pro GIT 9NHM1C45G44B Unknown msstore
My Git 9NLVK2SL2SSP Unknown msstore
GitCup 9NBLGGH4XFHP Unknown msstore
GitVine 9P3BLC2GW78W Unknown msstore
GitFiend 9NMNKLTSZNKC Unknown msstore
GitIt 9NBLGGH40HV7 Unknown msstore
GitHub Zen 9NBLGGH4RTK3 Unknown msstore
GitLooker 9PK6TGX9T87P Unknown msstore
Bhagavad Gita 9WZDNCRFJCV5 Unknown msstore
Git Git.Git 2.33.1 winget
GitNote zhaopengme.gitnote 3.1.0 Tag: git winget
Agent Git Xidicone.AgentGit 1.85 Tag: Git winget
TortoiseSVN TortoiseSVN.TortoiseSVN 1.14.29085 Tag: git winget
TortoiseGit TortoiseGit.TortoiseGit 2.12.0.0 Tag: git winget
After you have found the package you want, installing it is as easy as invoking the following command:
winget install --id <SomePackage>
Of course the real fun starts when you create a script that contains all the packages you need for you day-to-day work. Here is the script I’m using:
Today I helped out a colleague who was struggling with the following use case:
We have an ASP.NET Core Web API with OpenAPI(Swagger) integration enabled. This ASP.NET Core Web API was running behind a reverse proxy(Yarp in case you want to know) and isn’t directly accessibel.
To explain the problem he had, let’s start from the following situation:
When browsing to the Swagger endpoint on https://localhost/proxy/swagger, we got the following:
Do you notice the application url in the address bar vs the url in the Servers dropdown?
If we try to invoke a specific endpoint through the Swagger UI, Swagger tries to do the call directly to http://internalname:5000 which results in 404 error as the service is not available directly on this address.
It seems that Swagger doesn’t respect the Forwarded headers as provided through Yarp.
We fixed it by explicitly reading out the X-Forwarded-Host value and using it to fill up the servers dropdown:
After deploying an application to production, it failed with the following error message:
The system cannot find the file specified
Internal.Cryptography.CryptoThrowHelper+WindowsCryptographicException: at Internal.Cryptography.Pal.CertificatePal.FilterPFXStore (System.Security.Cryptography.X509Certificates, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) at Internal.Cryptography.Pal.CertificatePal.FromBlobOrFile (System.Security.Cryptography.X509Certificates, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) at System.Security.Cryptography.X509Certificates.X509Certificate..ctor (System.Security.Cryptography.X509Certificates, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) at System.Security.Cryptography.X509Certificates.X509Certificate2..ctor (System.Security.Cryptography.X509Certificates, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
Let’s take a look at the code that caused this issue:
Not much I could do wrong with this code. It tries to load a PFX file from disk and open it using the specified password.
I checked if the file was there and that was indeed the case. So we have to search for the root cause somewhere else.
I took a look at the Application Pool settings and noticed that the Load User Profile setting was set to False.
Aha! After changing this back to True the error got away…
What is Dapr?
Dapr helps developers build event-driven, resilient distributed applications. Whether on-premises, in the cloud, or on an edge device, Dapr helps you tackle the challenges that come with building microservices and keeps your code platform agnostic.
The Dapr ecosystem keeps growing and now they’ll have their first virtual conference ‘DaprCon’ next week. DaprCon will include a variety of content including a keynote, technical sessions, panel discussions and real-world experiences of adopters building with Dapr
DaprCon is a fully virtual event that will be streamed on YouTube and attendance is free! To watch the live events just follow these two links:
More information: https://blog.dapr.io/posts/2021/10/05/join-us-for-daprcon-october-19th-20th-2021/
MassTransit dedicated a whole documentation page to message versioning but it still wasn’t completely clear to me how it worked.
Let’s use this blog post to see what’s going on…
Let’s first focus on the sending side.
We’ll start with a first version of our message contract:
Let’s send this to RabbitMQ using:
Time to open the RabbitMQ Management portal and take a look how the message payload is constructed:
Let’s introduce a v2 version of our message contract:
If we send it to RabbitMQ in the same way:
There isn’t such a big difference when comparing the payloads:
The ‘messagetype’ value is different and of course the message itself. But that’s it.
Let’s now construct a message that implements both contracts:
And send that one:
If we now check the payload, we see that 1 message is put on the queue with the following payload:
Take a look at the ‘messagetype’. You can see that it contains both the 2 messagecontracts AND the concrete message type we created:
"messageType": [
"urn:message:Sender:Program+SubmitOrderCommand",
"urn:message:Messages:SubmitOrder",
"urn:message:Messages:SubmitOrderV2"
],
Now we have a good understanding on what is going on at the sending side, let’s move on to the consuming side.
Let’s create a consumer for that consumes v1 of our message contract:
And subscribe this consumer:
After publishing a ‘SubmitOrder’ message, our consumer is called as expected.
> Old Order consumed
Let’s create a consumer for that consumes v2 of our message contract:
And subscribe this consumer:
After publishing a ‘SubmitOrderV2’ message, our consumer is called as expected.
> New Order consumed
So far nothing special.
The question is what happens when we send our ‘SubmitOrderCommand’ that implements both message contracts.
If we have only one consumer subscribed the behavior is completely the same as before and either the old or the new consumer is called.
But if we have both consumers subscribed:
Each one will get a copy of the message and be called:
> Old Order consumed
> New Order consumed
Ok, that is good to now. But what happens if one of the consumers now fail?
Althought the first consumer is called succesfully, the message will still end up on the error queue:
If we then move the message back to the original queue, both consumers will be called again.
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