Load balancing error with WCF service - NLB

问题

UPDATE 3:
I created a Visual Studio 2008 test project and tried to create a service reference to shared site WCF service reference and received the following error:

There was an error downloading 'http://apps.mydomain/MyService.svc'. The request failed with HTTP status 400: Bad Request. Metadata contains a reference that cannot be resolved: 'http://apps.mydomain/MyService.svc'. Content Type application/soap+xml; charset=utf-8 was not supported by service http://apps.mydomain/MyService.svc'. The client and service bindings may be mismatched. The remote server returned an error: (415) Cannot process the message because the content type 'application/soap+xml; charset=utf-8' was not the expected type 'text/xml; charset=utf-8'.. If the service is defined in the current solution, try building the solution and adding the service reference again.

UPDATE 2:
@Nick - I tried your suggestion of explictly setting the address of each endpoint with the fully qualified path of each server and I still get the same result.

Also, when I try to set the listenUri attribute with the shared site URL, I get a 400 bad request error instead of a 404 error.

UPDATE
After some additional research, there were some IIS configuration setting conflicts between http://apps1.mydomain and http://apps2.mydomain and was able to get past the "Server Application Unavailable" error.

Now I am getting a 404 error when I tried to browse to the shared site (http://apps.mydomain), but I am able to browse to the http://apps1.mydomain and http://apps2.mydomain service reference.

Original Problem

My companys uses Microsoft NLB to load balance traffic between our IIS servers. I recently deployed a WCF service on to each IIS 6 Windows Server 2003 Standard Edition SP1 servers. I received the following error when I tried to browse to the shared domain name using IE 7:

Server Application Unavailable The web application you are attempting to access on this web server is currently unavailable. Please hit the "Refresh" button in your web browser to retry your request.

Administrator Note: An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur.

The consumer will point to the http://apps.mydomain to use the service but virtual domain is mapped to http://apps1.mydomain or http://apps2.mydomain. If I browse to the service on each server, I do not receive that error.

The service is currently using a anonymous basicHttpBinding.

Has anyone else experienced this issue?

History

Before this error started occurring, I received the following error when I broswed to all three domain name (http://apps.mydomain, http://apps1.mydomain, http://apps2.mydomain):

This collection already contains an address with scheme http. There can be at most one address per scheme in this collection.

I used the ServiceHostFactory class to customize my .svc file to specify a custom service factory. Then I create our custom factory by inheriting from ServiceHostFactory and overriding as required.

public class MyFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
    {
        return new ServiceHost(serviceType, baseAddresses[0]);
    }
}

<%@ ServiceHost Language="C#" Factory="MyFactory" Debug="true" Service="MyService" CodeBehind="~/App_Code/MyService.cs" %>

回答1:

After some experimenting with different configurations for my WCF service and consuming application. I created a service reference to one of the working service references (http://apps1.mydomain or http://apps2.mydomain) in the consuming application. Then I changed the endpoint reference in the client configuration to point to the shared site WCF address (http://apps.mydomain) and I was able to consume and use the service.

回答2:

I've had an issue before with WCF and load balancing where the servers had multiple Network cards with different IP addresses and WCF would just pic the first IP address it found. We had to explicitly set the IP address on each server's Service Definition so WCF would bind to the right one.

来源：https://stackoverflow.com/questions/475076/load-balancing-error-with-wcf-service-nlb