Skip to main content

2012R2, IIS, and KB3052480 - random ASP.NET app domain restarts

I will leave out the 'how we came to this conclusion' part, but suffice to say it took 3 people the better part of 2 full days.

There is a, in my humble opinion, rather gaping bug in 2012R2 IIS that manifests itself like this:

  • You have many file changes in the web root, but they are contained to the 'safe' directories (i.e. not in /bin or whatnot)
  • In theory, IIS doesn't care and you go about your merry way - because it only monitors /bin and /app_data (iirc?) and some config files
  • You find yourself chasing spikes in your (New Relic) data, traces that make no sense (the transactions that get called the most have a lot of looong traces)
  • Nobody understands what's going on, because no errors are being thrown
You can verify that you're seeing a lot of ASP.NET app domain restarts by looking at perfmon:
ASP.NET Applications - (your instance) - Application Lifetime Events

What you should be seeing upon a legit recycle is one startup event and one shutdown event, and possibly a 'compilation started' event.

What happened in our case is that (we suspect) Launch Darkly log files were being written to a lot (which is fine), but IIS was detecting these as configuration changes.  We found that by adding a <healthMonitoring> rule in: C:\Windows\Microsoft.NET\Framework64\Config\web.config

<add name="Application Lifetime Events Default" 
 eventName="Application Lifetime Events" 
 custom="" />

Do an iisreset and you'll see log start to come into the application event log.

EventID: 1309
Source: ASP.NET 4.0.30319.0
Event code: 1002
Event messsage: Application is shutting down. Reason: Configuration has changed.
Event detail code: 50004

A lot of googling/digging later, we turned up this hotfix:

After applying the hotfixes and rebooting the servers (yes, it prompts you to restart even though the documentation states otherwise), we have seen ZERO app domain restarts.


Unexpected ASP.Net application shutdown after many App_Data file changes occur on a server that is running Windows Server 2012 R2

Consider the following scenario:
  • You have a server that is running Windows Server 2012 R2.
  • You set up a website on Internet Information Services (IIS).
  • You create a simple website that creates or deletes lots of files in the App_Data folder.

In this scenario, you experience an unexpected ASP.NET application shutdown because of high disk I/O and configuration changes.


Popular posts from this blog

DFSR - eventid 4312 - replication just won't work

This warning isn't documented that well on the googles, so here's some google fodder:

You are trying to set up replication for a DFS folder (no existing replication)Source server is 2008R2, 'branch office' server is 2012R2 (I'm moving all our infra to 2012R2)You have no issues getting replication configuredYou see the DFSR folders get created on the other end, but nothing stagesFinally you get EventID 4312:
The DFS Replication service failed to get folder information when walking the file system on a journal wrap or loss recovery due to repeated sharing violations encountered on a folder. The service cannot replicate the folder and files in that folder until the sharing violation is resolved.  Additional Information:  Folder: F:\Users$\\Desktop\Random Folder Name\  Replicated Folder Root: F:\Users$  File ID: {00000000-0000-0000-0000-000000000000}-v0  Replicated Folder Name: Users  Replicated Folder ID: 33F0449D-5E67-4DA1-99AC-681B5BACC7E5  Replication Group…

Fixing duplicate SPNs (service principal name)

This is a pretty handy thing to know:

SPNs are used when a specific service/daemon uses Kerberos to authenticate against AD. They map a specific service, port, and object together with this convention: class/host:port/name

If you use a computer object to auth (such as local service):

If you use a user object to auth (such as a service account, or admin account):

Why do we care about duplicate SPNs? If you have two entries trying to auth using the same Kerberos ticket (I think that's right...), they will conflict, and cause errors and service failures.

To check for duplicate SPNs:
The command "setspn.exe -X

C:\Windows\system32>setspn -X
Processing entry 7
MSSQLSvc/ is registered on these accounts:
CN=SQL Admin,OU=service accounts,OU=resources,DC=company,DC=local

found 1 groups of duplicate SPNs. (truncated/sanitized)

Note that y…

Logstash to Nagios - alerting based on Windows Event ID

This took way longer than it should have to get here's a config and brain dump...

You want to have a central place to analyze Windows Event/IIS/local application logs, alert off specific events, alert off specific situations.  You don't have the budget for a boxed solution.  You want pretty graphs.  You don't particularly care about individual server states.  (see rationale below - although you certainly have all the tools here to care, I haven't provided that configuration)

ELK stack, OMD, NXlog agent, and Rsyslog.  The premise here is as follows:

Event generated on server into EventLogNXlog ships to Logstash inputLogstash filter adds fields and tags to specified eventsLogstash output sends to a passive Nagios service via the Nagios NSCA outputThe passive service on Nagios (Check_MK c/o OMD) does its thing w. alerting
Open Monitoring Distribution, but the real point here is Check_MK (IIRC Icinga uses this...).  It makes Nagios easy to use and main…