Configure Azure web role to start app domain on launch

Question

Azure has a fantastic ability to roll updates so that the entire system is not offline all at once. However, when Azure updates my web roles, the AppDomains are understandably recycled. Sometimes the ASP.NET startup code can take over a minute to finish initializing, and that's only once a user hits the new server.

Can I get Azure to start the AppDomain for the site and wait for it to come up before moving on to the next server? Perhaps using some magic in the OnStart method of WebRole?

Answer 1

See Azure Autoscale Restarts Running Instances which includes the following code:

public class WebRole : RoleEntryPoint
{
    public override bool OnStart()
    {
        // For information on handling configuration changes
        // see the MSDN topic at http://go.microsoft.com/fwlink/?LinkId=166357.
        IPHostEntry ipEntry = Dns.GetHostEntry(Dns.GetHostName());
        string ip = null;
        foreach (IPAddress ipaddress in ipEntry.AddressList)
        {
            if (ipaddress.AddressFamily.ToString() == "InterNetwork")
            {
                ip = ipaddress.ToString();
            }
        }

        string urlToPing = "http://" + ip;
        HttpWebRequest req = HttpWebRequest.Create(urlToPing) as HttpWebRequest;
        WebResponse resp = req.GetResponse();
        return base.OnStart();
    }
}