Thursday, March 05, 2015

About CQS, CQRS and Event Sourcing

Seems to be a lot of confusion going on about these terms. The below extract form Greg Young explains it all:
Many people have been getting confused over what CQRS is. They look at CQRS as being an architecture; it is not. CQRS is a very simple pattern that enables many opportunities for architecture that may otherwise not exist. CQRS is not eventual consistency, it is not eventing, it is not messaging, it is not having separated models for reading and writing, nor is it using event sourcing. I want to take a few paragraphs to describe first exactly what CQRS is and then how it relates to other patterns.


Thursday, May 15, 2014

What is the difference between IaaS, Paas and SaaS?

Software as a Service (SaaS)

This has been around as long as the internet exists. These are pieces of software that you can subscribe to, like for instance Gmail,, office 365 but as well as Adobe's creative cloud for instance. The main characteristics of this model is that you always are up to date with the latest version. If you take the example of (Hotmail), Microsoft will not ask you to update it, you cannot rollback to a previous version. This off course will require from the provider that they always have to ensure continuity of their service. Since I as a customer would not appreciate it that I would not be able to read the emails in my inbox I received or sent 5 years ago.

Platform as a Service (PaaS)

In Microsoft azure these are all the features Microsoft makes available to you the only thing you need to worry about is get your code on there and Microsoft will keep all these features up to date to the latest versions. You have little or no Control over the Operation System or the underlying Infrastructure. In return off course you get certain things in return. For instance in Azure Websites You can have zero downtime scaling, high availability, and failover. Cloud Services provide you with more control in configuring the underlying infrastructure but that's it, you cannot install additional components on these features like a SQL server, you get an OS, an IIS and that's it, there is however some control in the version of the underlying OS and network (expose additional endpoints, deploy on a virtual network, etc). 

Infrastructure as a Service (IaaS)

These are basically virtual machine, the customer is responsible to monitor and maintain the OS and install and maintain the necessary features on these Virtual Machines like e.g. IIS, MSMQ, …
It's all matter of what you want to do yourself, are willing to do yourself

Scott Hanselman provides a very good analogy with regards to this:

Tuesday, April 29, 2014

Microsoft Azure VPN: Error 0x8007274c whilst trying to connect

When trying to connect you are getting the below error message:

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
 (Error 0x8007274c)

try to upload the root certificate again.

Wednesday, April 23, 2014

Microsoft Azure: Reducing Cost

If you plan to use IaaS make sure you have a sound monitoring strategy that you have reporting on the load and performance of your Virtual Machines.


As the above graph shows that the virtual machine is not used during the last 7 days. This is a very good candidate to look a little bit deeper into. After doing some root cause analysis it is a standard small vm running linux costing your company around € 33.25 / a month. If we would scale down this application from Standard to Basic we would save € 5.54 / month which would be a cost reduction of ~17%. Since it seems that this virtual machine is underutilized for most of the time (CPU anyways) we could scale it down from S to XS bring down the cost even further from € 27.71 to € 9.98 which would save us an additional 64 %. Doing this it would mean that we would bring down out monthly cost from €33.25 to € 9.98 saving us 70%.
If we would take it a step further we could investigate the type of application that is running on this serer and maybe migrate it to a PaaS solution bringing the cost even further down. In this case the VM was running a very simple website hosting this in a shared website we could even bring the cost further down to € 7.21 which would our bring our total savings to 92%.

The cloud is not only about up scaling it is all about optimizing cost! This means that if needed you can scale up and or out but it means you can scale down and in as well saving your company money. This is a very very simple example. But if you would closely analyze usage and optimize your scaling strategy, the potential cost savings can be quite significant. This was a case which I came across in my company, the figures are representative and taken from the Microsoft pricing calculator which can be found at:, not taken into account any EA reductions.


Monday, March 24, 2014

Sunday, February 23, 2014

Problem Running application in IISExpress in Visual Studio over SSL

I Currently set up an Azure VM to use as a development machine, I used MSDN's Default Visual Studio 2013 Image.

When I try to run my web application locally Internet Explorer gives me a "This page can't be displayed" error... firefox gives me "The connection was reset".
When browsing to the default non https port everything works as expected though...

so the solution:

1. uninstall iisexpress 8.0 (Control Panel > Uninstall a program)
2. mmc.exe, Add/Remove snapp-in, Certificates, select  Local Computer (Click Next), Finish
   here look under Personal, Certificates and delete the certificate Friendly Name = "IIS Express Development Certificate"
3. Reinstall IIS Express 8.0
4. following actions outlined in step 2. find the new "IIS Express Development Certificate", double click and goto details, find the thumbprint and copy the hash: ‎38 b3 05 a5 d2 1c ba 8b cb 45 fa 03 06 9a d4 b6 94 00 97 f9
5. remove the spaces from the hash: ‎38b305a5d21cba8bcb45fa03069ad4b6940097f9
open an elevated command prompt.
netsh http show sslcert > sslcert.txt

look for the entry matching your port. In my case it was this:
    IP:port                      :
    Certificate Hash             : f5584bb1e88d4240d962bec7120e5a90302ff3b9
    Application ID               : {214124cd-d05b-4309-9af9-9caa44b2b74a}
    Certificate Store Name       : MY
    Verify Client Certificate Revocation : Enabled
    Verify Revocation Using Cached Client Certificate Only : Disabled
    Usage Check                  : Enabled
    Revocation Freshness Time    : 0
    URL Retrieval Timeout        : 0
    Ctl Identifier               : (null)
    Ctl Store Name               : (null)
    DS Mapper Usage              : Disabled
    Negotiate Client Certificate : Disabled

netsh http delete sslcert ipport=
netsh http add sslcert ipport= appid={214124cd-d05b-4309-9af9-9caa44b2b74a} certhash=38b305a5d21cba8bcb45fa03069ad4b6940097f9

Hanselman's blog

Wednesday, February 19, 2014

Bootstrap: 404 Not Found on .woff files

When using bootstrap I got the following message in my firefox console:

"NetworkError: 404 Not Found -"

Add the following lines to your web.config



Friday, September 06, 2013

Windows Identity Framework Signing out

When using claims based security and you implement the sign out functionality do not forget to delete the sessions cookie... otherwise when playing around with the back button you are able to sign in again... this is something you don't want...

Loading ....

Monday, June 17, 2013

MVC: Intellisense for custom HtmlHelpers or if you want to avoid @using to import namespaces

If you write custom HtmlHelpers its quite tedious to have to add @using on top of each page. To be able to use your newly written htmlhelpers

to avoid this just find the web.config in your views folder and locate the following section:
        <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
        <pages pageBaseType="System.Web.Mvc.WebViewPage">
                <add namespace="System.Web.Mvc" />
                <add namespace="System.Web.Mvc.Ajax" />
                <add namespace="System.Web.Mvc.Html" />
                <add namespace="System.Web.Optimization"/>
                <add namespace="System.Web.Routing" />
                <add namespace="SharpSolutions..MvcApplication.Helpers.BootStrap"/>
                <add namespace="SharpSolutions.MvcApplication.Helpers"/>

and add your custom namespace to it.

After you have done this reload your mvc project (or close Visual Studio and reopen it).

Tuesday, June 11, 2013

Windows Azure Logging not working Trace.TraceError throws: Not running in a hosted service or the Development Fabric.

I had the following line in my web.config:

    <add type="Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener, Microsoft.WindowsAzure.Diagnostics, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
     <filter type="" />

After removing this: it created WAWSAppLogTable as expected.
More info can be found here:

for local debugging I left the line untouched... I created a new config transformation where I added:

    <add name="AzureDiagnostics" xdt:Locator="Match(name)" xdt:Transform="Remove" />

Which is quite logic since Azure websites is not hosted in the AppFabrik