为什么Azure托管API会为ASP._Page_Views_Home_Index_cshtml.Execute（）抛出NullReferenceException？

Question

我们有一个位于Azure上的ASP.Net Core API，具有2个实例（有时为3个）。在看似随机的时间，Azure回收应用程序并同时向两个实例发送重新启动命令。当两个尝试恢复时，它们会收到以下错误

<Data>w3wp.exe</Data>
<Data>NullReferenceException</Data>
<Data>Object reference not set to an instance of an object.
   at ASP._Page_Views_Home_Index_cshtml.Execute()
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
   at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
   at System.Web.WebPages.StartPage.RunPage()
   at System.Web.WebPages.StartPage.ExecutePageHierarchy()
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   at System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance)
   at System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer)
   at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.&lt;&gt;c__DisplayClass21.&lt;&gt;c__DisplayClass2b.&lt;BeginInvokeAction&gt;b__1c()
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.&lt;&gt;c__DisplayClass21.&lt;BeginInvokeAction&gt;b__1e(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult)
   at System.Web.Mvc.Controller.&lt;BeginExecuteCore&gt;b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
   at System.Web.Mvc.Controller.&lt;BeginExecute&gt;b__15(IAsyncResult asyncResult, Controller controller)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult)
   at System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult)
   at System.Web.Mvc.MvcHandler.&lt;BeginProcessRequest&gt;b__5(IAsyncResult asyncResult, ProcessRequestState innerState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
   at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)
   at System.Web.HttpApplication.CallHandlerExecutionStep.InvokeEndHandler(IAsyncResult ar)
   at System.Web.HttpApplication.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar)
</Data>

同样，这是一个API。没有Razor引擎，也没有.cshtml页面。甚至没有家庭/索引路径。 一旦发生这种情况，实例看起来就很健康（根据Azure的Resource Health刀片服务器），但是没有请求可以通过。它们都会变慢直到超时（Http 502.3）。 我们唯一的解决方案是每隔3分钟手动对每个实例执行一次高级重启。但这并不总是能在第一次尝试时就起作用。 还有一个问题是，为什么Azure可能会回收应用程序（日志指向更改了全局配置，但我们没有做任何事情），为什么它会在同一时间而不是单独地重新启动两个实例，以避免停机。 我们已与支持人员联系，但他们仍在调查中。我想也许我可以在这里找到答案。 预先感谢！