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Xianyin Xin commented on YARN-4477: ----------------------------------- cc [~asuresh]. > FairScheduler: encounter infinite loop in attemptScheduling > ----------------------------------------------------------- > > Key: YARN-4477 > URL: https://issues.apache.org/jira/browse/YARN-4477 > Project: Hadoop YARN > Issue Type: Bug > Components: fairscheduler > Reporter: Tao Jie > > This problem is introduced by YARN-4270 which add limitation on reservation. > In FSAppAttempt.reserve(): > {code} > if (!reservationExceedsThreshold(node, type)) { > LOG.info("Making reservation: node=" + node.getNodeName() + > " app_id=" + getApplicationId()); > if (!alreadyReserved) { > getMetrics().reserveResource(getUser(), container.getResource()); > RMContainer rmContainer = > super.reserve(node, priority, null, container); > node.reserveResource(this, priority, rmContainer); > setReservation(node); > } else { > RMContainer rmContainer = node.getReservedContainer(); > super.reserve(node, priority, rmContainer, container); > node.reserveResource(this, priority, rmContainer); > setReservation(node); > } > } > {code} > If reservation over threshod, current node will not set reservation. > But in attemptScheduling in FairSheduler: > {code} > while (node.getReservedContainer() == null) { > boolean assignedContainer = false; > if (!queueMgr.getRootQueue().assignContainer(node).equals( > Resources.none())) { > assignedContainers++; > assignedContainer = true; > > } > > if (!assignedContainer) { break; } > if (!assignMultiple) { break; } > if ((assignedContainers >= maxAssign) && (maxAssign > 0)) { break; } > } > {code} > assignContainer(node) still return FairScheduler.CONTAINER_RESERVED, which not > equals to Resources.none(). > As a result, if multiple assign is enabled and maxAssign is unlimited, this > while loop would never break. > I suppose that assignContainer(node) should return Resource.none rather than > CONTAINER_RESERVED when the attempt doesn't take the reservation because of > the limitation. -- This message was sent by Atlassian JIRA (v6.3.4#6332)