I know this is something repetead but couldn't find the solution to my problem...
I am trying to implement a simulated distributed system and I struggling a lot with the connectivity through RMI.
I have three different components, grid schedulers, resources managers and clients. The three of them interact among themselves. The behaviour is the following: the user looks up resource manager reference on the registry and then invokes a remote method which will invoke another one in the grid scheduler and eventually one method in the user will be invoked delivering the results. If I execute the whole system in local everything works as expected.
Now the thing is, I am trying to move one of the resource mananger nodes to a EC2 Amazon instance with public address A.A.A.A, the rest of the system will run locally on my laptop with public address B.B.B.B. I allowed TCP traffic on the port 1099 TCP/UDP on the security group policy, also set the java.security.policy to grant all permision in both machines. To create the registry in every component I do:
LocateRegistry.createRegistry(1099);
Then the components will discover themselves by
Naming.lookup(url)
Now, user will look up for ip address A.A.A.A/component the public address of the Amazon instance. I can check that sometimes it gets the reference, sometimes it doesn't (NotBoundException). However, when it does gets the reference and tries to call the method I get:
java.rmi.ConnectException: Connection refused to host: INTERNAL IP OF AMAZON INSTANCE nested exception is: java.net.ConnectException: Connection timed out: connec.
Am I doing something wrong? I tried to set the property
java.rmi.server.hostname
To the public ip A.A.A.A in the Amazon instance and I got same results. I also tried doing the same on my laptop to the public address B.B.B.B and I got "connection refused IP B.B.B.B is not a localhost address"
I also opened the port in the router of my houe just in case that's the problem but it doesn't seem to be...
Am I missing something?
Thanks in advance.
Okay apparently, the issue was that even if the server listens on port 1099 then the port you use to connect the stub is random so I had to open all TCP ports in the security group of AWS. In that way it's working, however even if I turned off my windows firewall and open all the ports in the router it wasn't working my laptop - AWS, just different instances in AWS. But well, I can live with that...
Regarding the hostname you have to set it to the private address returned by
hostname -i
If you're going to deploy it inside AWS or to the public IP if you're connecting different instances such as your laptop and one EC2.
I hope this helps people on the same situation (have seen couple of questions with the same issue but no response).
Have a nice day!