Silo as IHostedService on Azure App Service

Summary

It works just fine when there is only one instance within the App Service Plan. Problems start when I scale out.

Background

I’m using an App Service Plan with 2x S3 instances inside of it. The silo is started as a singleton IHostedService that I’ve implemented. It is running within a .NET Core 2.0 API that translates the HTTP traffic into Grain calls. In this scenario GrainClient and Silo are both within the same application. First silo starts fine. Second silo gets stuck in “Joining” state, which then transitions to “Dead”.

Configuration

Orleans version: 2.0-beta3

SiloConfiguraton.xml

<OrleansConfiguration xmlns="urn:orleans">
<Globals>
  <SystemStore SystemStoreType="AzureTable"
               DeploymentId="MyDeployment"
               DataConnectionString="removed-for-github" />
  <Liveness LivenessType="AzureTable" />
</Globals>
<Defaults>
  <Networking Address="" Port="11111" />
  <ProxyingGateway Address="" Port="40000" />
</Defaults>
</OrleansConfiguration>

ClientConfiguration.xml

<ClientConfiguration xmlns="urn:orleans">
  <SystemStore SystemStoreType="AzureTable"
               DeploymentId="MyDeployment"
               DataConnectionString="removed-for-github" />
</ClientConfiguration>

Questions

• Should I update to the recently released 2.0-rc1 Orleans?
• Have I provided enough information?

CC @sergeybykov

[turowicz]

That’s what I’ll have to do then. It would be so nice if Orleans could work on App Service. I did try to make it work by detecting which port is the process listening on but even though port was open they couldn’t connect over the “internal” network - probably due to proxy that you mention.

[Liversage]

do you think it is possible to run a Silo in App Service with instance count >1?

No, I don’t think it is possible. As far as I know an App Service is proxied by a web server listening on port 80 and 443. Running one instance works fine because your process listens on the loopback adapter without any “real” network communication. However, if you scale out the instances are unable to communicate.

You can connect an App Service to a Virtual Network using VNET Integration. This allows you to host your Orleans cluster on VMs or some other “execution mechanism” and connect an Orleans client in the App Service to the cluster connected to the Virtual Network.