/// <exception cref="Org.Apache.Hadoop.Yarn.Server.Resourcemanager.Reservation.Exceptions.ContractValidationException
/// "/>
private void ValidateInput(Plan plan, ReservationRequest rr, Resource totalCapacity
)
{
if (rr.GetConcurrency() < 1)
{
throw new ContractValidationException("Gang Size should be >= 1");
}
if (rr.GetNumContainers() <= 0)
{
throw new ContractValidationException("Num containers should be >= 0");
}
// check that gangSize and numContainers are compatible
if (rr.GetNumContainers() % rr.GetConcurrency() != 0)
{
throw new ContractValidationException("Parallelism must be an exact multiple of gang size"
);
}
// check that the largest container request does not exceed
// the cluster-wide limit for container sizes
if (Resources.GreaterThan(plan.GetResourceCalculator(), totalCapacity, rr.GetCapability
(), plan.GetMaximumAllocation()))
{
throw new ContractValidationException("Individual" + " capability requests should not exceed cluster's maxAlloc"
);
}
}
/// <summary>
/// This method actually perform the placement of an atomic stage of the
/// reservation.
/// </summary>
/// <remarks>
/// This method actually perform the placement of an atomic stage of the
/// reservation. The key idea is to traverse the plan backward for a
/// "lease-duration" worth of time, and compute what is the maximum multiple of
/// our concurrency (gang) parameter we can fit. We do this and move towards
/// previous instant in time until the time-window is exhausted or we placed
/// all the user request.
/// </remarks>
private IDictionary <ReservationInterval, ReservationRequest> PlaceSingleStage(Plan
plan, RLESparseResourceAllocation tempAssigned, ReservationRequest rr, long earliestStart
, long curDeadline, ReservationAllocation oldResAllocation, Org.Apache.Hadoop.Yarn.Api.Records.Resource
totalCapacity)
{
IDictionary <ReservationInterval, ReservationRequest> allocationRequests = new Dictionary
<ReservationInterval, ReservationRequest>();
// compute the gang as a resource and get the duration
Org.Apache.Hadoop.Yarn.Api.Records.Resource gang = Resources.Multiply(rr.GetCapability
(), rr.GetConcurrency());
long dur = rr.GetDuration();
long step = plan.GetStep();
// ceil the duration to the next multiple of the plan step
if (dur % step != 0)
{
dur += (step - (dur % step));
}
// we know for sure that this division has no remainder (part of contract
// with user, validate before
int gangsToPlace = rr.GetNumContainers() / rr.GetConcurrency();
int maxGang = 0;
// loop trying to place until we are done, or we are considering
// an invalid range of times
while (gangsToPlace > 0 && curDeadline - dur >= earliestStart)
{
// as we run along we remember how many gangs we can fit, and what
// was the most constraining moment in time (we will restart just
// after that to place the next batch)
maxGang = gangsToPlace;
long minPoint = curDeadline;
int curMaxGang = maxGang;
// start placing at deadline (excluded due to [,) interval semantics and
// move backward
for (long t = curDeadline - plan.GetStep(); t >= curDeadline - dur && maxGang > 0
; t = t - plan.GetStep())
{
// As we run along we will logically remove the previous allocation for
// this reservation
// if one existed
Org.Apache.Hadoop.Yarn.Api.Records.Resource oldResCap = Org.Apache.Hadoop.Yarn.Api.Records.Resource
.NewInstance(0, 0);
if (oldResAllocation != null)
{
oldResCap = oldResAllocation.GetResourcesAtTime(t);
}
// compute net available resources
Org.Apache.Hadoop.Yarn.Api.Records.Resource netAvailableRes = Resources.Clone(totalCapacity
);
Resources.AddTo(netAvailableRes, oldResCap);
Resources.SubtractFrom(netAvailableRes, plan.GetTotalCommittedResources(t));
Resources.SubtractFrom(netAvailableRes, tempAssigned.GetCapacityAtTime(t));
// compute maximum number of gangs we could fit
curMaxGang = (int)Math.Floor(Resources.Divide(plan.GetResourceCalculator(), totalCapacity
, netAvailableRes, gang));
// pick the minimum between available resources in this instant, and how
// many gangs we have to place
curMaxGang = Math.Min(gangsToPlace, curMaxGang);
// compare with previous max, and set it. also remember *where* we found
// the minimum (useful for next attempts)
if (curMaxGang <= maxGang)
{
maxGang = curMaxGang;
minPoint = t;
}
}
// if we were able to place any gang, record this, and decrement
// gangsToPlace
if (maxGang > 0)
{
gangsToPlace -= maxGang;
ReservationInterval reservationInt = new ReservationInterval(curDeadline - dur, curDeadline
);
ReservationRequest reservationRes = ReservationRequest.NewInstance(rr.GetCapability
(), rr.GetConcurrency() * maxGang, rr.GetConcurrency(), rr.GetDuration());
// remember occupied space (plan is read-only till we find a plausible
// allocation for the entire request). This is needed since we might be
// placing other ReservationRequest within the same
// ReservationDefinition,
// and we must avoid double-counting the available resources
tempAssigned.AddInterval(reservationInt, reservationRes);
allocationRequests[reservationInt] = reservationRes;
}
// reset our new starting point (curDeadline) to the most constraining
// point so far, we will look "left" of that to find more places where
// to schedule gangs (for sure nothing on the "right" of this point can
// fit a full gang.
curDeadline = minPoint;
}
// if no gangs are left to place we succeed and return the allocation
if (gangsToPlace == 0)
{
return(allocationRequests);
}
else
{
// If we are here is becasue we did not manage to satisfy this request.
// So we need to remove unwanted side-effect from tempAssigned (needed
// for ANY).
foreach (KeyValuePair <ReservationInterval, ReservationRequest> tempAllocation in
allocationRequests)
{
tempAssigned.RemoveInterval(tempAllocation.Key, tempAllocation.Value);
}
// and return null to signal failure in this allocation
return(null);
}
}
