Service Fabric Multiple service instances with config override

Question

Our service fabric application includes a stateless service that exposes an HTTP endpoint through OwinCommunicationListener.

The ServiceManifest.Xml for this service specifies the service endpoint <Endpoint Name="ServiceEndpoint" Type="Input" Protocol="http" Port="8090" />

The stateless service can then be accessed via a browser on http://localhost:8090/

What we are trying to do is instantiate multiple instances of this service on different endpoints in the same Service Fabric application through the ApplicationManifest.

The ServiceManifestImport imports our service package and allows configuration overrides at the application level. We're not able to override the ServiceEndpoint this way, only the values in Settings.xml

<ServiceManifestImport>
  <ServiceManifestRef ServiceManifestName="FooServicePkg" ServiceManifestVersion="1.0.0" >
    <ConfigOverrides Name="Config">
      <Settings>
        <SectionName Name="MySettings">
        <Parameter Name="MySetting" Value="SomeValue">
      </Settings>
    </ConfigOverrides>
</ServiceManifestImport>

We can create named instances of the service by specifying multiple Service nodes under DefaultServices

<DefaultServices>
  <Service Name="FooInstanceA">
    <StatelessService ServiceTypeName="FooType" InstanceCount="1" />
      <SingletonPartition />
    </StatelessService>
  </Service>
  <Service Name="FooInstanceB">
    <StatelessService ServiceTypeName="FooType" InstanceCount="1" />
      <SingletonPartition />
    </StatelessService>
  </Service>
</DefaultServices>

Is it possible to specify configuration overrides per instance of a service through configuration?

I tried to make the service instances listen on a specific port by using their service name to work out which port so FooInstanceA listens on port 8090 and FooInstanceB listens on 8091.

Clearly Service Fabric is doing some magic during deployment because when FooInstanceB listens on a port other than the one specified on the ServiceEndpoint configuration the service is not accessible.

The first reason is the DACL is not set on the endpoint, this is resolved by running;

netsh http add urlacl http://+:8091/ user=everyone listen=yes

This allows the services to come up and show healthy in the Service Fabric Explorer, however the FooInstanceB is responding with an HTTP 503 error when we access with http://localhost:8091/

How can we get the service instances listening on different ports?

I hope that's clear, thank you.

Answer 1

Not a lot of great options to accomplish this. Here are some ideas:

1. Create multiple application instances instead of multiple services of the same type within an app. That would allow you to use the app parameters to configure the behavior of the particular service.
2. Create multiple config packages within your service type. Each config package would be intended for one of the service instances. Determining which config package a service instance is assigned to would need to be dynamic, maybe based on the service instance's name? Not a great option, of course, since it couples the service definition with the number of instances that will be created.
3. A custom configuration implementation. Maybe have your service expose an endpoint that allows you to configure it post-deployment. Or have the service call some other management service that provides its configuration at activation time.