func (s *GenericStack) Select(tg *structs.TaskGroup) (*RankedNode, *structs.Resources) {
// Reset the max selector and context
s.maxScore.Reset()
s.ctx.Reset()
start := time.Now()
// Collect the constraints, drivers and resources required by each
// sub-task to aggregate the TaskGroup totals
constr := make([]*structs.Constraint, 0, len(tg.Constraints))
drivers := make(map[string]struct{})
size := new(structs.Resources)
constr = append(constr, tg.Constraints...)
for _, task := range tg.Tasks {
drivers[task.Driver] = struct{}{}
constr = append(constr, task.Constraints...)
size.Add(task.Resources)
}
// Update the parameters of iterators
s.taskGroupDrivers.SetDrivers(drivers)
s.taskGroupConstraint.SetConstraints(constr)
s.binPack.SetTasks(tg.Tasks)
// Find the node with the max score
option := s.maxScore.Next()
// Ensure that the task resources were specified
if option != nil && len(option.TaskResources) != len(tg.Tasks) {
for _, task := range tg.Tasks {
option.SetTaskResources(task, task.Resources)
}
}
// Store the compute time
s.ctx.Metrics().AllocationTime = time.Since(start)
return option, size
}
func (iter *BinPackIterator) Next() *RankedNode {
OUTER:
for {
// Get the next potential option
option := iter.source.Next()
if option == nil {
return nil
}
// Get the proposed allocations
proposed, err := option.ProposedAllocs(iter.ctx)
if err != nil {
iter.ctx.Logger().Printf(
"[ERR] sched.binpack: failed to get proposed allocations: %v",
err)
continue
}
// Index the existing network usage
netIdx := structs.NewNetworkIndex()
netIdx.SetNode(option.Node)
netIdx.AddAllocs(proposed)
// Assign the resources for each task
total := new(structs.Resources)
for _, task := range iter.tasks {
taskResources := task.Resources.Copy()
// Check if we need a network resource
if len(taskResources.Networks) > 0 {
ask := taskResources.Networks[0]
offer, err := netIdx.AssignNetwork(ask)
if offer == nil {
iter.ctx.Metrics().ExhaustedNode(option.Node,
fmt.Sprintf("network: %s", err))
continue OUTER
}
// Reserve this to prevent another task from colliding
netIdx.AddReserved(offer)
// Update the network ask to the offer
taskResources.Networks = []*structs.NetworkResource{offer}
}
// Store the task resource
option.SetTaskResources(task, taskResources)
// Accumulate the total resource requirement
total.Add(taskResources)
}
// Add the resources we are trying to fit
proposed = append(proposed, &structs.Allocation{Resources: total})
// Check if these allocations fit, if they do not, simply skip this node
fit, dim, util, _ := structs.AllocsFit(option.Node, proposed, netIdx)
if !fit {
iter.ctx.Metrics().ExhaustedNode(option.Node, dim)
continue
}
// XXX: For now we completely ignore evictions. We should use that flag
// to determine if its possible to evict other lower priority allocations
// to make room. This explodes the search space, so it must be done
// carefully.
// Score the fit normally otherwise
fitness := structs.ScoreFit(option.Node, util)
option.Score += fitness
iter.ctx.Metrics().ScoreNode(option.Node, "binpack", fitness)
return option
}
}