Modifying machine.config on Azure compute instances

Question

I want to change the process model, unfortunately this is not allowed in runtime or in your Web Role web.config file, the setting is only allowed in the machine.config file.

<processModel maxWorkerThreads="100" maxIoThreads="100" minWorkerThreads="50"/>

What is the best way to go about changing the machine.config file on all Azure compute instances at once?

The default process model settings are not optimal for my application:

Minimum number of worker threads per CPU in the CLR thread pool: 1

Maximum amount of worker threads per CPU in the CLR thread pool: 20

Maximum number of I/O threads per CPU in the CLR thread pool: 20

Answer 1

After some more investigation I found that maxWorkerThreads has been replaced by MaxConcurrentRequestsPerCPU after IIS 7 and .NET 4 was released , see http://social.msdn.microsoft.com/Forums/en-US/windowsazuretroubleshooting/thread/cbc1f1bb-9ff6-4fef-8ef2-fa3547747449/ and http://msdn.microsoft.com/en-us/library/ee377050(v=bts.10).aspx for more information.

Answer 2

In general, make changes like this in startup tasks. A batch file running appcmd is probably the easiest way to do it for IIS settings.