Akka.Net Clustering Simple Explanation - cluster-computing

Question

I try to do a simple cluster using akka.net.
The goal is to have a server receiving request and akka.net processing it through it cluster.
For testing and learning I create a simple WCF service that receive a math equation and I want to send this equation to be solved.
I have one project server and another client.
The configuration on the server side is :
<![CDATA[
akka {
actor {
provider = "Akka.Cluster.ClusterActorRefProvider, Akka.Cluster"
debug {
receive = on
autoreceive = on
lifecycle = on
event-stream = on
unhandled = on
}
deployment {
/math {
router = consistent-hashing-group #round-robin-pool # routing strategy
routees.paths = [ "/user/math" ]
virtual-nodes-factor = 8
#nr-of-instances = 10 # max number of total routees
cluster {
enabled = on
max-nr-of-instances-per-node = 2
allow-local-routees = off
use-role = math
}
}
}
}
remote {
helios.tcp {
transport-class = "Akka.Remote.Transport.Helios.HeliosTcpTransport, Akka.Remote"
applied-adapters = []
transport-protocol = tcp
port = 8081
hostname = "127.0.0.1"
}
}
cluster {
seed-nodes = ["akka.tcp://ClusterSystem#127.0.0.1:8081"] # address of seed node
}
}
]]>
On the Client side the configuration is like this :
<![CDATA[
akka {
actor.provider = "Akka.Cluster.ClusterActorRefProvider, Akka.Cluster"
remote {
log-remote-lifecycle-events = DEBUG
log-received-messages = on
helios.tcp {
transport-class = "Akka.Remote.Transport.Helios.HeliosTcpTransport, Akka.Remote"
applied-adapters = []
transport-protocol = tcp
port = 0
hostname = 127.0.0.1
}
}
cluster {
seed-nodes = ["akka.tcp://ClusterSystem#127.0.0.1:8081"] # address of the seed node
roles = ["math"] # roles this member is in
}
actor.deployment {
/math {
router = round-robin-pool # routing strategy
routees.paths = ["/user/math"]
nr-of-instances = 10 # max number of total routees
cluster {
enabled = on
allow-local-routees = on
use-role = math
max-nr-of-instances-per-node = 10
}
}
}
}
]]>
The cluster connection seems to correctly be made. I see the status [UP] and the association with the role "math" that appeared on the server side.
Event follwing the example on the WebCramler, I don't achieved to make a message to be delivered. I always get a deadletters.
I try like this :
actor = sys.ActorOf(Props.Empty.WithRouter(FromConfig.Instance), "math");
or
var actor = sys.ActorSelection("/user/math");
Does someone know a good tutorial or could help me ?
Thanks

Answer 1

Some remarks:
First: assuming your sending work from the server to the client. Then you are effectively remote deploying actors on your client.
Which means only the server node needs the actor.deployment config section.
The client only needs the default cluster config (and your role setting ofcourse).
Second: Try to make it simpler first. Use a round-robin-pool instead. Its much simpler. Try to get that working. And work your way up from there.
This way its easier to eliminate configuration/network/other issues.
Your usage: actor = sys.ActorOf(Props.Empty.WithRouter(FromConfig.Instance), "math"); is correct.
A sample of how your round-robin-pool config could look:
deployment {
/math {
router = round-robin-pool # routing strategy
nr-of-instances = 10 # max number of total routees
cluster {
enabled = on
max-nr-of-instances-per-node = 2
allow-local-routees = off
use-role = math
}
}
}
Try this out. And let me know if that helps.
Edit:
Ok after looking at your sample. Some things i changed
ActorManager->Process: Your creating a new router actor per request. Don't do that. Create the router actor once, and reuse the IActorRef.
Got rid of the minimal cluster size settings in the MathAgentWorker project
Since your not using remote actor deployment. I changed the round-robin-pool to a round-robin-group.
After that it worked.
Also remember that if your using the consistent-hashing-group router you need to specify the hashing key. There are various ways to do that, in your sample i think the easiest way would be to wrap the message your sending to your router in a ConsistentHashableEnvelope. Check the docs for more information.
Finally the akka deployment sections looked like this:
deployment {
/math {
router = round-robin-group # routing strategy
routees.paths = ["/user/math"]
cluster {
enabled = on
allow-local-routees = off
use-role = math
}
}
}
on the MathAgentWorker i only changed the cluster section which now looks like this:
cluster {
seed-nodes = ["akka.tcp://ClusterSystem#127.0.0.1:8081"] # address of the seed node
roles = ["math"] # roles this member is in
}
And the only thing that the ActorManager.Process does is:
return await Program.Instance.RouterInstance.Ask<TResult>(msg, TimeSpan.FromSeconds(10));