Azure role entry with config for hot-start of sites

HostApplication.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using Microsoft.Web.Administration;
using Microsoft.WindowsAzure.ServiceRuntime;

namespace Kwd.Web
{
  /// <summary>
  /// Application azure host.
  /// </summary>
  public class HostApplication : RoleEntryPoint
  {
    private readonly string[] _hotSites;

    public HostApplication()
    {
      //Site's from ServiceDefinition.def
      _hotSites = new string[] { "Web" };
    }

    #region RoleEntryPoint
    public override bool OnStart()
    {
      bool res = base.OnStart();

      if (res){ this.ConfigureHotStartSites(); }

      return res;
    }
    #endregion

    /// <summary>
    /// Config role(s) for hot-start.
    /// </summary>
    /// <remarks>
    /// Finding Mgmt Assem: http://blog.stronico.com/2010/01/how-to-fix-the-microsoft-web-administration-dll-problem/
    /// Scrap doco for iis mgmt: http://www.iis.net/learn/manage/scripting/how-to-use-microsoftwebadministration
    /// Class: http://msdn.microsoft.com/en-us/library/ee758619.aspx
    /// Usage: http://brentdacodemonkey.wordpress.com/2011/09/24/leveraging-the-roleentrypoint-year-of-azure-week-12/
    /// AppPool: http://blog.elastacloud.com/2011/01/26/windows-azure-apppool-settings-programmatic-modification/
    /// Note: must have elevated excutionContext in web-role.
    /// </remarks>
    public void ConfigureHotStartSites()
    {
      Trace.TraceInformation("Configuring hot start sites.");

      foreach (var siteName in SiteNames())
      {
        using (var serverManager = new ServerManager())
        {
          Application application = null;
          ApplicationPool appPool = null;

          var site = serverManager.Sites.SingleOrDefault(s => s.Name == siteName);

          if (site != null){
            application = site.Applications.FirstOrDefault();
          }

          if (application != null) {
            appPool = serverManager.ApplicationPools.SingleOrDefault(p => p.Name == application.ApplicationPoolName);
          }

          if (appPool != null) {
            appPool["startMode"] = "AlwaysRunning";
            appPool.ProcessModel.IdleTimeout = new TimeSpan(0);
          }

          if (application != null) {
            application["preloadEnabled"] = "true";
          }

          if (appPool == null || application == null) {
            Trace.TraceError("Failed to configure site {0}", siteName);
          } else {
            Trace.TraceInformation("Site {0} first application configured for hot start", siteName);
          }

          serverManager.CommitChanges();
        }
      }
    }

    public IEnumerable<string> SiteNames()
    {
      foreach (var item in _hotSites) { 
        var siteName = String.Format("{0}_{1}"
            , RoleEnvironment.CurrentRoleInstance.Id
            ,item);

        yield return siteName;
      }
    }
  }
}