Azure HTTP request timeout workaround

Question

We currently have an application hosted on a Azure VM instance.

This application sometimes processes long-running and idle HTTP requests. This is causing an issue because Azure will close all connections that have been idle for longer than a few minutes.

I've seen some suggestions about setting a lower TCP keepalive rate. I've tried setting the this rate to around 45 seconds but my HTTP requests are still being closed.

Any suggestions? Our VM is running Server 2008 R2.

Roadrunner

what is the reference for "Azure will close all connections that have been idle for longer than a few minutes." ? – Winchell

@dorin blogs.msdn.com/b/cie/archive/2014/02/14/… – Shavonneshaw

Answer 1

As a simple workaround, I had my script send a newline character every 5 seconds or so to keep the connection alive.

Example:

set_time_limit(60 * 30);
ini_set("zlib.output_compression", 0);
ini_set("implicit_flush", 1);

function flushBuffers()
{
    @ob_end_flush();
    @ob_flush();
    @flush();
    @ob_start();
}

function azureWorkaround($char = "\n")
{
    echo $char;
    flushBuffers();
}

$html = '';
$employees = getEmployees();
foreach($employee in $employees) {
    html .= getReportHtmlForEmployee($employee);
    azureWorkaround();
}

echo $html;

Roadrunner

Can you provide some code to show how you did this? – Shipowner

Updated with example. – Roadrunner

Answer 2

The Azure Load Balancer now supports configurable TCP Idle timeout for your Cloud Services and Virtual Machines. This feature can be configured using the Service Management API, PowerShell or the service model.

For more information check the announcement at http://azure.microsoft.com/blog/2014/08/14/new-configurable-idle-timeout-for-azure-load-balancer/

Lactone

how to find where my wcf hosted in azure? (Cloud Services or Virtual Machines) – Upcast

Can i configure tcp idle timeout for app services(i hosted wcf inside my webapp which uses appservices)? – Upcast