So, I need to submit computation intensive jobs (deep neural network training) to a torque cluster that lease computation time on, and I need to exchange a few megs of large float arrays every few minutes between the active nodes, as the nodes need to be working on the most recent version of the neural network in order to train it well.
I was wondering if there were any good communication options, at least to tell each active job its sisters jobs' ips so it can connect to them by tcp. The nodes don't have access to the internet, and we can't have daemons working on the job submitting server.
The only options that I see would be:
- some message passing option on Torque (I'm am fairly noob at torque)
- the very error prone option of using files to communicate, which I hate.
- a way to query the ips of the active nodes from the server.
There are a variety of ways to exchange information between nodes on a cluster, depending on the architecture of the cluster. Torque is a resource manager, so if the job is being submitted to the cluster using a batch script there are a few environment variables that should be able to give you the hostnames or IP addresses of the nodes being used on a job.
The exact syntax for finding the IP addresses and/or hostnames will depend on the scheduler/workload manager being used with Torque on your cluster. This link has documentation for the PBS Works workload manager.
Parallel communication between nodes can be achieved in a variety of ways and will be partly dependent on the hardware available in the cluster. Using MPI is one of the most common ways to parallelize code for use on a cluster and many implementations support multiple high-performance fabrics/interconnect systems like Infiniband. Some useful introductions to the different types of parallelism can be found here.
As an alternative to MPI Remote Direct Memory Access(RDMA) can be used to pass and access information between nodes. If the cluster has Infiniband network adapters looking into the IB-Verbs API from the vendor would be an additional option for passing data between nodes.