// inplaceUpdate attempts to update allocations in-place where possible.
func inplaceUpdate(ctx Context, eval *structs.Evaluation, job *structs.Job,
stack Stack, updates []allocTuple) []allocTuple {
n := len(updates)
inplace := 0
for i := 0; i < n; i++ {
// Get the update
update := updates[i]
// Check if the task drivers or config has changed, requires
// a rolling upgrade since that cannot be done in-place.
existing := update.Alloc.Job.LookupTaskGroup(update.TaskGroup.Name)
if tasksUpdated(update.TaskGroup, existing) {
continue
}
// Get the existing node
node, err := ctx.State().NodeByID(update.Alloc.NodeID)
if err != nil {
ctx.Logger().Printf("[ERR] sched: %#v failed to get node '%s': %v",
eval, update.Alloc.NodeID, err)
continue
}
if node == nil {
continue
}
// Set the existing node as the base set
stack.SetNodes([]*structs.Node{node})
// Stage an eviction of the current allocation. This is done so that
// the current allocation is discounted when checking for feasability.
// Otherwise we would be trying to fit the tasks current resources and
// updated resources. After select is called we can remove the evict.
ctx.Plan().AppendUpdate(update.Alloc, structs.AllocDesiredStatusStop,
allocInPlace)
// Attempt to match the task group
option, size := stack.Select(update.TaskGroup)
// Pop the allocation
ctx.Plan().PopUpdate(update.Alloc)
// Skip if we could not do an in-place update
if option == nil {
continue
}
// Restore the network offers from the existing allocation.
// We do not allow network resources (reserved/dynamic ports)
// to be updated. This is guarded in taskUpdated, so we can
// safely restore those here.
for task, resources := range option.TaskResources {
existing := update.Alloc.TaskResources[task]
resources.Networks = existing.Networks
}
// Create a shallow copy
newAlloc := new(structs.Allocation)
*newAlloc = *update.Alloc
// Update the allocation
newAlloc.EvalID = eval.ID
newAlloc.Job = job
newAlloc.Resources = size
newAlloc.TaskResources = option.TaskResources
newAlloc.Metrics = ctx.Metrics()
newAlloc.DesiredStatus = structs.AllocDesiredStatusRun
newAlloc.ClientStatus = structs.AllocClientStatusPending
newAlloc.PopulateServiceIDs()
ctx.Plan().AppendAlloc(newAlloc)
// Remove this allocation from the slice
updates[i] = updates[n-1]
i--
n--
inplace++
}
if len(updates) > 0 {
ctx.Logger().Printf("[DEBUG] sched: %#v: %d in-place updates of %d", eval, inplace, len(updates))
}
return updates[:n]
}