如何判断IIS应用程序池的回收原因

Question

背景:

我已经在我的机器上部署了一个ASP.NET MVC 3应用程序到共享主机提供程序,并且发现了一些似乎与正在回收的应用程序池相关的问题.主机已配置在以下任何情况下进行回收:

• 内存使用量超过200MB
• CPU使用率超过75%(可能持续一段时间)
• 20分钟的空闲时间

我的开发机器上的限制更加轻松,所以在开发过程中我没有看到像这样的回收.我没有管理员访问共享主机盒(可以理解),所以我无法阅读事件日志,看看为什么这种回收正在发生.

题:

有没有办法可以找出为什么我的应用程序被回收(Application_End例如),以便我可以记录它来帮助我的调试？

Answer 1

如果没有访问事件日志(因为您处于共享托管环境中),您将获得的最多信息来自Application_End事件,并通过询问HttpRuntime(通过反射)一两个私人成员的值,这是令人遗憾的不公开曝光.

为此,请将以下代码添加到您的Application_End活动中:

BindingFlags staticFlags = 
    BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.GetField;
BindingFlags instanceFlags = 
    BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField;

HttpRuntime runtime = (HttpRuntime)typeof(System.Web.HttpRuntime)
                        .InvokeMember("_theRuntime", staticFlags, null, null, null);
if(runtime != null) 
{
    string shutDownMessage = (string)runtime.GetType()
         .InvokeMember("_shutDownMessage", instanceFlags, null, runtime, null);

    string shutDownStack = (string)runtime.GetType()
         .InvokeMember("_shutDownStack", instanceFlags, null, runtime, null);

    // Log shutDownMessage & shutDownStack somewhere
}

如果我关闭或回收我的应用程序的应用程序池,我会看到以下内容:

HostingEnvironment initiated shutdown
HostingEnvironment caused shutdown -    
   at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
   at System.Environment.get_StackTrace()
   at System.Web.Hosting.HostingEnvironment.InitiateShutdownInternal()
   at System.Web.Hosting.HostingEnvironment.InitiateShutdownWithoutDemand()
   at System.Web.Hosting.PipelineRuntime.StopProcessing()

这可能和它一样好.

更新:

我不记得我在哪里找到了这段代码,但Drew提醒我这是来自Scott Guthrie博客文章.

还有一些其他私人成员可能有用,例如:

private ApplicationShutdownReason _shutdownReason;

您可以在.NET Reflector中检查这些字段(如果您还有一个没有时间轰炸的副本)或其中一个替代方案(Reflector的开源替代方案？).

Answer 2

研究 - 1

首先我尝试使用System.Web.ProcessModelInfo.GetCurrentProcessInfo()和System.Web.ProcessModelInfo.GetHistory(int).这些方法的结果返回信息,例如PID,开始时间,年龄,状态和峰值内存使用情况.不幸的是,这些在我的托管环境中不可用

HttpException 0x80004005 - 仅当启用ASP.NET进程模型时,进程度量标准才可用.在工作进程隔离模式下运行IIS 6或更高版本时,不支持此功能.

这种方法可能适用于其他人,所以如果你处于这种情况,那就试一试吧.

研究 - 2

该属性System.Web.Hosting.HostingEnvironment.ShutdownReason是一个包含大量值的枚举,但不幸的是,我在我的问题中概述的所有情况都捆绑在一个枚举值中:

ApplicationShutdownReason.HostingEnvironment:托管环境关闭应用程序域.

研究 - 3

ScottGu在他的博客上有一种方法(这是Kev发布的相同代码),它使用反射来访问内部状态HttpApplication.不幸的是,在这种情况下,它只报告与上面#2相同的细节:

_shutDownMessage =
  HostingEnvironment initiated shutdown
  HostingEnvironment caused shutdown

_shutDownStack =
  at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
  at System.Environment.get_StackTrace()
  at System.Web.Hosting.HostingEnvironment.InitiateShutdownInternal()
  at System.Web.Hosting.HostingEnvironment.InitiateShutdownWithoutDemand()
  at System.Web.Hosting.PipelineRuntime.StopProcessing()

Answer 3

下面是从https://mitchelsellers.com/blog/article/logging-asp-net-application-restarts找到的好代码

//  obtain the shutdown reason
System.Web.ApplicationShutdownReason shutdownReason = System.Web.Hosting.HostingEnvironment.ShutdownReason;
string shutdownDetail = "";

//Evaluate which option caused the error
switch (shutdownReason)
{
    case ApplicationShutdownReason.BinDirChangeOrDirectoryRename:
        shutdownDetail = "A change was made to the bin directory or the directory was renamed";
        break;
    case ApplicationShutdownReason.BrowsersDirChangeOrDirectoryRename:
        shutdownDetail = "A change was made to the App_browsers folder or the files contained in it";
        break;
    case ApplicationShutdownReason.ChangeInGlobalAsax:
        shutdownDetail = "A change was made in the global.asax file";
        break;
    case ApplicationShutdownReason.ChangeInSecurityPolicyFile:
        shutdownDetail = "A change was made in the code access security policy file";
        break;
    case ApplicationShutdownReason.CodeDirChangeOrDirectoryRename:
        shutdownDetail = "A change was made in the App_Code folder or the files contained in it";
        break;
    case ApplicationShutdownReason.ConfigurationChange:
        shutdownDetail = "A change was made to the application level configuration";
        break;
    case ApplicationShutdownReason.HostingEnvironment:
        shutdownDetail = "The hosting environment shut down the application";
        break;
    case ApplicationShutdownReason.HttpRuntimeClose:
        shutdownDetail = "A call to Close() was requested";
        break;
    case ApplicationShutdownReason.IdleTimeout:
        shutdownDetail = "The idle time limit was reached";
        break;
    case ApplicationShutdownReason.InitializationError:
        shutdownDetail = "An error in the initialization of the AppDomain";
        break;
    case ApplicationShutdownReason.MaxRecompilationsReached:
        shutdownDetail = "The maximum number of dynamic recompiles of a resource limit was reached";
        break;
    case ApplicationShutdownReason.PhysicalApplicationPathChanged:
        shutdownDetail = "A change was made to the physical path to the application";
        break;
    case ApplicationShutdownReason.ResourcesDirChangeOrDirectoryRename:
        shutdownDetail = "A change was made to the App_GlobalResources foldr or the files contained within it";
        break;
    case ApplicationShutdownReason.UnloadAppDomainCalled:
        shutdownDetail = "A call to UnloadAppDomain() was completed";
        break;
    default:
        shutdownDetail = "Unknown shutdown reason";
        break;
}

Answer 4

这是一个非常晚的答案，但我希望它可以为那些有类似问题（IIS 7.x 或更高版本）的人提供额外的见解。

1. 查找应用程序池何时开始关闭- 以下代码可用于查找应用程序池何时开始关闭。实际关闭发生在此事件后的最大关闭限制（秒，默认为 90）内。

public class ApplicationPoolService : IApplicationPoolService
{
    public bool IsShuttingDown()
    {
        return System.Web.Hosting.HostingEnvironment.ShutdownReason != ApplicationShutdownReason.None;
    }

    public ApplicationShutdownReason GetShutdownReason()
    {
        return System.Web.Hosting.HostingEnvironment.ShutdownReason;
    }
}

public class HostingEnvironmentRegisteredObject : IRegisteredObject
{
    public void Stop(bool immediate)
    {
        // second call is done when the Stop is imminent 
        if (immediate)
            return;

        var reason = appPoolService.GetShutdownReason().ToString();
        logger.Log(LogLevel.Info, $"HostingEnvironmentRegisteredObject.stop called with shutdown reason {reason}");
    }
}

// this code should be placed in global.asax.cs
protected void Application_Start()
{
    HostingEnvironment.RegisterObject(new HostingEnvironmentRegisteredObject());
}

这有助于找到一般原因以及触发的确切时间。在你的情况下，我认为HostingEnvironment是价值。不幸的是，根本原因并不是唯一的。它可以是定期回收，由于内存限制而回收（OP 问题中最可能的原因），由于固定时间回收等。

2. 查找确切原因-查找确切原因的一种方法是在 EventLog 中搜索。如果无法访问，可以通过提供以下详细信息向托管服务提供商请求以缩小搜索范围。

• 关机启动的确切时间
• 事件日志过滤器：
  • 事件源 = WAS
  • 事件级别 = 信息
  • 记录 = 自定义范围，包括准确的关机时间 +/- 1 分钟左右

事件日志应返回更多相关信息，如下所示：

服务应用程序池“xxx”的进程 ID 为“xxx”的工作进程已请求回收，因为它已达到预定的回收时间。

服务应用程序池“xxx”的进程 ID 为“xxx”的工作进程已请求回收，因为它已达到其虚拟内存限制。