// Schedule tries to schedule the given pod to one of node in the node list.
// If it succeeds, it will return the name of the node.
// If it fails, it will return a Fiterror error with reasons.
func (g *genericScheduler) Schedule(pod *api.Pod, nodeLister algorithm.NodeLister) (string, error) {
var trace *util.Trace
if pod != nil {
trace = util.NewTrace(fmt.Sprintf("Scheduling %s/%s", pod.Namespace, pod.Name))
} else {
trace = util.NewTrace("Scheduling <nil> pod")
}
defer trace.LogIfLong(20 * time.Millisecond)
nodes, err := nodeLister.List()
if err != nil {
return "", err
}
if len(nodes) == 0 {
return "", ErrNoNodesAvailable
}
// Used for all fit and priority funcs.
err = g.cache.UpdateNodeNameToInfoMap(g.cachedNodeInfoMap)
if err != nil {
return "", err
}
trace.Step("Computing predicates")
filteredNodes, failedPredicateMap, err := findNodesThatFit(pod, g.cachedNodeInfoMap, nodes, g.predicates, g.extenders)
if err != nil {
return "", err
}
if len(filteredNodes) == 0 {
return "", &FitError{
Pod: pod,
FailedPredicates: failedPredicateMap,
}
}
trace.Step("Prioritizing")
meta := g.priorityMetaProducer(pod)
priorityList, err := PrioritizeNodes(pod, g.cachedNodeInfoMap, meta, g.prioritizers, filteredNodes, g.extenders)
if err != nil {
return "", err
}
trace.Step("Selecting host")
return g.selectHost(priorityList)
}
