FAQ - Health Monitoring in ASP.NET 2.0

erikreitan — Mon, 22 May 2006 08:48:00 GMT

What is Health Monitoring?

Health Monitoring is a framework for monitoring status of running ASP.NET applications and logging significant ASP.NET application events.

Why would I use Health Monitoring?

Health Monitoring is runtime based for your production environment, so it provides information of your running ASP.NET applications
Health Monitoring gives event details rather than providing a number or a total, which can be useful to solve running application issues.
Health Monitoring is customizable, so you can tailor the event information they way you need it.

What are examples of Health Monitoring events that can be logged?

Application starts and stops
Failed logins and unhandled exceptions
"Heartbeats"
Successful and failed login attempts through Membership
Successful and failed URL and ACL authorizations by authenticated users
Valid and expired forms authentication tickets
View state validation failures
Compilation errors
Configuration errors
Unhandled exceptions
Request validation failures
Anything that causes request to abort
Requests queued, processing, or rejected
Specific or periodic monitoring event
Process start time and more

What are examples of locations where Health Monitoring events can be logged?

Windows event log
SQL Server database
Email
Console window using WMI
Trace output window

What are Health Monitoring events?

Health Monitoring events help you keep track of different things that are occurring while your ASP.NET application is running. These events are divided into five main areas:

Application Lifetime Events
All Audits
All Errors
Reqeust Processing Events
Heartbeats

What are Health Monitoring providers?

Providers consume Web event data. By default, the ASP.NET health-monitoring system can deliver Web event data using the built-in providers listed in the following table. More than one provider can listen for the same event, and more than one event can be consumed by the same provider.

Event Providers	Details
EventLogWebEventProvider	Writes Web event data to the Windows event log. By default, this provider is configured to write all errors to the Windows event log. Security operation errors are logged under the event name `Failure Audits` and logs all other errors are logged under the event name `All Errors`. To read event log data, you can view data using the Windows Event Viewer or read event log data programmatically.
SqlWebEventProvider	Logs Web event data to a Microsoft SQL server database. By default, this provider logs data to the SQL Server Express database in the Web application's App_Data folder. It does not subscribe to any events by default.
WmiWebEventProvider	Passes Web events to WMI, converting them to WMI events. By default, this provider does not subscribe to any events. To listen for WMI events, you can build an application such as the one illustrated in Walkthrough: Listening for WMI Events in ASP.NET Health Monitoring. For more information, see Using WMI to Deliver ASP.NET Health Monitoring Events. WMI applications do not have to be written in managed code.
SimpleMailWebEventProvider and TemplatedMailWebEventProvider	Sends an e-mail message when Web events are raised. By default, these providers are not configured and do not subscribe to any events.
TraceWebEventProvider	Passes event data to the ASP.NET page tracing system. By default, this provider is not configured and does not subscribe to any events. Tracing provides you the ability to start and stop event tracing sessions, to instrument applications to provide trace events, and to consume trace events. You can use the events to debug an application and perform capacity and performance analysis. For more information, see ASP.NET Tracing.

What are Health Monitoring profiles?

Profiles determine how events are collected by ASP.NET and raised to providers.

By default, there are two profiles named Critical and Default included in the configuration.

What are Health Monitoring buffers?

Buffers (BufferModes) define how health-monitoring events can be buffered before they are raised. The three included providers that can use bufferModes are:

SqlWebEventProvider (included by default)
SimpleMailWebEventProvider
TemplatedMailWebEventProvider

Each of the above providers inherits from the BufferedWebEventProvider class.

What are Health Monitoring rules?

The rules define the map of how an event is raised. At a minimum each rule must list the event name, the provider and the profile.

How is Health Monitoring configured and controlled?

The configuration is the main location to control what events will be monitored and how those events will be monitored. You can either modify the configuration using a text editor or use the API. For more information see, HealthMonitoringSection Class and ASP.NET Configuration Files.

Where in the configuration is Health Monitoring found?

The <healthMonitoring> section is within the <system.web> section of the configuration.

What are the sub-sections within the <healthMonitoring> section of the configuration?

There are five sub-sections within the <healthMonitoring> section. The Health Monitoring section looks like the following:

...

</bufferModes>

...

</providers>

...

</eventMappings>

...

</profiles>

<rules>

...

</rules>

</healthMonitoring>

Are there default values (a default configuration) established in the <healthMonitoring> section of the configuration?

Yes. These values are contained at the root web.config file. The root web.config file is located at %windir%\Microsoft.NET\Framework\v2.0.50727\CONFIG. By default, a number of eventMappings, providers, profiles, rules, and bufferModes are already established within the <heathMonitoring> section.

What are the default Health Monitoring events included in the configuration?

The default events are mapped in the root web.config file:

<add name="HeartBeats"

type="System.Web.Management.WebHeartBeatEvent, ..." />

<add name="Application Lifetime Events"

type="System.Web.Management.WebApplicationLifetimeEvent, ..." />

<add name="Request Processing Events"

type="System.Web.Management.WebRequestEvent, ..." />

<add name="All Errors"

type="System.Web.Management.WebBaseErrorEvent, ..." />

<add name="Infrastructure Errors"

type="System.Web.Management.WebErrorEvent, ..." />

<add name="Request Processing Errors"

type="System.Web.Management.WebRequestErrorEvent, ..." />

<add name="Failure Audits"

type="System.Web.Management.WebFailureAuditEvent, ..." />

<add name="Success Audits"

type="System.Web.Management.WebSuccessAuditEvent, ..." />

</eventMappings>

What are the default Health Monitoring providers included in the configuration?

The default providers are included in the following section of the root web.config file:

<add name="EventLogProvider"

type="System.Web.Management.EventLogWebEventProvider, …

<add name="SqlWebEventProvider"

connectionStringName="LocalSqlServer"

maxEventDetailsLength="1073741823"

buffer="false"

bufferMode="Notification"

type="System.Web.Management.SqlWebEventProvider, …

<add name="WmiWebEventProvider"

type="System.Web.Management.WmiWebEventProvider,…

</providers>

What are the default Health Monitoring profiles included in the configuration?

The default profiles are included in the following section of the root web.config file:

<add name="Default"

minInstances="1"

maxLimit="Infinite"

minInterval="00:01:00"

custom="" />

<add name="Critical"

minInstances="1"

maxLimit="Infinite"

minInterval="00:00:00"

custom="" />

</profiles>

What are the default Health Monitoring buffers included in the configuration?

The default bufferModes are included in the following section of the root web.config file:

<add name="Critical Notification"

maxBufferSize="100"

maxFlushSize="20"

urgentFlushThreshold="1"

regularFlushInterval="Infinite"

urgentFlushInterval="00:01:00"

maxBufferThreads="1" />

<add name="Notification"

…

</>

<add name="Analysis"

…

</>

<add name="Logging“

…

</>

</bufferModes>

What are the default Health Monitoring rules included in the configuration?

The default rules are included in the following section of the root web.config file:

<rules>

<add name="Failure Audits Default"

eventName="Failure Audits"

provider="EventLogProvider"

profile="Default"

minInterval="00:00:00"

minInstances="1"

maxLimit="Infinite"

...

</rules>

I understand the basics of Health Monitoring, but I still don’t understand exactly how to implement it. How can I get started using Health Monitoring right now?

Follow the steps below:

1. Create a new Web application in Visual Web Developer.

2. From the Website menu select Add New Item.

3. Select and add a Web Configuration File.

4. Add the following node before the end of the <system.web> node in the newly added configuration file:

<rules>

<add name="Heartbeats Default"

eventName="Heartbeats"

provider="EventLogProvider"

profile="Critical"/>

</rules>

</healthMonitoring>

5. Run your Web application.

6. Run the Event Viewer (eventvwr.exe).

7. Select Application in the right pane of the Event Viewer.

8. Notice that the “heartbeat” events for your application occur every 10 seconds.

What would be an example of using the SqlWebEventProvider to log monitoring event?

There is an example on the ASP.NET site that demonstrates the SqlWebEventProvider.

I understand that the root web.config file contains the default Health Monitoring support. What should I do if I want to modify the <healthMonitoring> section?

There are three points to note:

Use the Add, Remove, and Clear elements
Do not modify the root level config files
Modify using text editor or the API.

I understand that event friendly names are mapped to the event type within the configuration, but how can I find the exact events that are related to each friendly event name, such as “All Audits”?

Take a look at the WebEventCodes on MSDN. This list will give you a more specific list of events.

In the Event Viewer I see the event code (i.e. 1005) but how can I match that code to the specific event?

The list below will help you match the event code name with the event code number.

WebEventCode	Event Code
InvalidEventCode	-1
UndefinedEventCode	0
UndefinedEventDetailCode	0
ApplicationCodeBase	1000
ApplicationStart	1001
ApplicationShutdown	1002
ApplicationCompilationStart	1003
ApplicationCompilationEnd	1004
ApplicationHeartbeat	1005
RequestCodeBase	2000
RequestTransactionComplete	2001
RequestTransactionAbort	2002
ErrorCodeBase	3000
RuntimeErrorRequestAbort	3001
RuntimeErrorViewStateFailure	3002
RuntimeErrorValidationFailure	3003
RuntimeErrorPostTooLarge	3004
RuntimeErrorUnhandledException	3005
WebErrorParserError	3006
WebErrorCompilationError	3007
WebErrorConfigurationError	3008
WebErrorOtherError	3009
WebErrorPropertyDeserializationError	3010
WebErrorObjectStateFormatterDeserializationError	3011
AuditCodeBase	4000
AuditFormsAuthenticationSuccess	4001
AuditMembershipAuthenticationSuccess	4002
AuditUrlAuthorizationSuccess	4003
AuditFileAuthorizationSuccess	4004
AuditFormsAuthenticationFailure	4005
AuditMembershipAuthenticationFailure	4006
AuditUrlAuthorizationFailure	4007
AuditFileAuthorizationFailure	4008
AuditInvalidViewStateFailure	4009
AuditUnhandledSecurityException	4010
AuditUnhandledAccessException	4011
MiscCodeBase	6000
WebEventProviderInformation	6001
ApplicationDetailCodeBase	50000
ApplicationShutdownUnknown	50001
ApplicationShutdownHostingEnvironment	50002
ApplicationShutdownChangeInGlobalAsax	50003
ApplicationShutdownConfigurationChange	50004
ApplicationShutdownUnloadAppDomainCalled	50005
ApplicationShutdownChangeInSecurityPolicyFile	50006
ApplicationShutdownBinDirChangeOrDirectoryRename	50007
ApplicationShutdownBrowsersDirChangeOrDirectoryRename	50008
ApplicationShutdownCodeDirChangeOrDirectoryRename	50009
ApplicationShutdownResourcesDirChangeOrDirectoryRename	50010
ApplicationShutdownIdleTimeout	50011
ApplicationShutdownPhysicalApplicationPathChanged	50012
ApplicationShutdownHttpRuntimeClose	50013
ApplicationShutdownInitializationError	50014
ApplicationShutdownMaxRecompilationsReached	50015
StateServerConnectionError	50016
AuditDetailCodeBase	50200
InvalidTicketFailure	50201
ExpiredTicketFailure	50202
InvalidViewStateMac	50203
InvalidViewState	50204
WebEventDetailCodeBase	50300
SqlProviderEventsDropped	50301
WebExtendedBase	100000

What are the details that get logged when a Health Monitoring event occurs?

The WebBaseEvent provides the details of the information that gets logged for each event:

public class WebBaseEvent : System.Object

{

public static WebApplicationInformation

ApplicationInformation { get; }

public int EventCode { get; }

public int EventDetailCode { get; }

public Guid EventId { get; }

public long EventOccurrence { get; }

public long EventSequence { get; }

public object EventSource { get; }

public DateTime EventTime { get; }

public DateTime EventTimeUtc { get; }

public string Message { get; }

public virtual void FormatCustomEventDetails (...);

public virtual void Raise (...);

}

For more information, see WebBaseEvent Members.

How can I modify the configuration of another Web application using C# code?

Follow the steps below:

1. Create a Web application with the following name “aspnetexample”. Use C# and HTTP (localhost).

2. Now create a new C# console application. Add the following code to the console application:

// Add references:

// System.Configuration

// System.Web

#region Using directives

using System;

using System.Collections.Generic;

using System.Text;

using System.Configuration;

using System.Web;

using System.Web.Configuration;

#endregion

namespace HealthMonExample

{

class UsingHealthMonitoringSection

{

static void Main(string[] args)

{

try

{

// Set the path of the config file.

string configPath = "/aspnetexample";

// Get the Web application configuration object.

Configuration config = WebConfigurationManager.OpenWebConfiguration(configPath);

// Get the section related object.

HealthMonitoringSection configSection =

(HealthMonitoringSection)config.GetSection("system.web/healthMonitoring");

// Display title and info.

Console.WriteLine("ASP.NET Configuration Info");

Console.WriteLine();

// Display Config details.

Console.WriteLine("File Path: {0}",

config.FilePath);

Console.WriteLine("Section Path: {0}",

configSection.SectionInformation.Name);

// Display Enabled property.

Console.WriteLine("Enabled (old value): {0}",

configSection.Enabled.ToString());

// Toggle the Enabled property.

if (!configSection.Enabled)

{

configSection.Enabled = true;

}

else

{

configSection.Enabled = false;

}

// Display Providers Count.

Console.WriteLine("Providers Count: {0}",

configSection.Providers.Count);

// Display EventMappings Count.

Console.WriteLine("EventMappings Count: {0}",

configSection.EventMappings.Count);

// Display Profiles Count.

Console.WriteLine("Profiles Count: {0}",

configSection.Profiles.Count);

// Display Rules Count.

Console.WriteLine("Rules Count: {0}",

configSection.Rules.Count);

// Update if not locked.

if (!configSection.SectionInformation.IsLocked)

{

config.Save();

Console.WriteLine("** Configuration updated.");

}

else

{

Console.WriteLine("** Could not update, section is locked.");

}

catch (Exception e)

{

// Unknown error.

Console.WriteLine(e.ToString());

}

// Display and wait

Console.ReadLine();

}

3. Be sure to add the following references to your console application:
System.Configuration
System.Web

4. Run the console application. You’ll notice that Health Monitoring of your web application is enabled or disabled each time you run the console application.

Can the Health Monitoring subsystem be extended?

Yes, you can create your own providers, events and other objects to help customize the monitoring of your ASP.NET applications. For more information, see Web Event Providers and WebBaseEvent Class.

Where can I find out more about Health Monitoring and related topics?

ASP.NET Health Monitoring

How to: Install and Configure SMTP Virtual Servers in IIS

How to: Send E-mail for Health Monitoring Notifications

Web Event Providers (Custom Provider Example)

ASP.NET SQL Server Registration Tool

WebEventCodes Class

Walkthrough: Listening for WMI Events in ASP.NET Health Monitoring

System.Web.Management Namespace

Erik Reitan's ASP.NET WebLog : Health Monitoring

FAQ - Health Monitoring in ASP.NET 2.0