App pool stopping and not logging any error

Question

We're having an issue in IIS on Windows Server 2012 R2 Core. Our IIS site has its own app pool which is set to run under the application pool identity. Almost immediately after startup when first accessing a page the app pool will stop.

I can restart the app pool and attempt to access a page and it will stop again, sometimes partially loading a page. The same is also true for accessing static content like CSS - it might load once, but a second attempt will yield a "Service Unavailable 503" response.

Nothing is being written to the application event log and the httperr.log files show the following:

2015-07-01 09:04:36 10.7.40.217 58318 195.47.225.106 80 HTTP/1.1 GET /Account/Login 503 14 AppOffline ourapp.ourdomain.com

We're tried a few things mentioned elsewhere like ensuring the loaduserprofile option is disabled for the app pool and disabling rapidFailProtection. Other users seem to report seeing errors logged to the application event log, but we're not seeing anything similar. Could these be being written elsewhere?

Solution

It turns out that the errors we were seeing were as a result of some patching that had occurred. A restart of the server resolved the issues.

Comments

[Kev]

Have you enabled Failed Request Tracing, you might get something logged there: iis.net/search?searchterm=failed%20request%20tracing Also check your httperr log files in: C:\Windows\System32\LogFiles\HTTPERR.

[AccuWebHosting.Com]

Here is a best guide to fix Service Unavailable 503 errors ... support.microsoft.com/en-us/kb/2619402