you need to refer the below file

https://github.com/kubernetes/kubernetes/blob/master/pkg/scheduler/core/generic_scheduler.go

below code snippet retrieves all the available nodes and a node is identified that is best suitable for running a specific pod

    nodes, err := nodeLister.List()
    if err != nil {
        return result, err
    }
    if len(nodes) == 0 {
        return result, ErrNoNodesAvailable
    }

    if err := g.snapshot(); err != nil {
        return result, err
    }

    trace.Step("Computing predicates")
    startPredicateEvalTime := time.Now()
    filteredNodes, failedPredicateMap, err := g.findNodesThatFit(pod, nodes)