ChenSammi commented on a change in pull request #1366: HDDS-1577. Add default pipeline placement policy implementation. URL: https://github.com/apache/hadoop/pull/1366#discussion_r320555432
########## File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/pipeline/PipelinePlacementPolicy.java ########## @@ -0,0 +1,291 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.hadoop.hdds.scm.pipeline; + +import com.google.common.annotations.VisibleForTesting; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hdds.protocol.DatanodeDetails; +import org.apache.hadoop.hdds.protocol.proto.HddsProtos; +import org.apache.hadoop.hdds.scm.ScmConfigKeys; +import org.apache.hadoop.hdds.scm.container.placement.algorithms.SCMCommonPolicy; +import org.apache.hadoop.hdds.scm.container.placement.metrics.SCMNodeMetric; +import org.apache.hadoop.hdds.scm.exceptions.SCMException; +import org.apache.hadoop.hdds.scm.net.NetworkTopology; +import org.apache.hadoop.hdds.scm.net.Node; +import org.apache.hadoop.hdds.scm.node.NodeManager; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; +import java.util.stream.Collectors; + +/** + * Pipeline placement policy that choose datanodes based on load balancing + * and network topology to supply pipeline creation. + * <p> + * 1. get a list of healthy nodes + * 2. filter out nodes that are not too heavily engaged in other pipelines + * 3. Choose an anchor node among the viable nodes which follows the algorithm + * described @SCMContainerPlacementCapacity + * 4. Choose other nodes around the anchor node based on network topology + */ +public final class PipelinePlacementPolicy extends SCMCommonPolicy { + @VisibleForTesting + static final Logger LOG = + LoggerFactory.getLogger(PipelinePlacementPolicy.class); + private final NodeManager nodeManager; + private final Configuration conf; + private final int heavyNodeCriteria; + + /** + * Constructs a Container Placement with considering only capacity. + * That is this policy tries to place containers based on node weight. + * + * @param nodeManager Node Manager + * @param conf Configuration + */ + public PipelinePlacementPolicy(final NodeManager nodeManager, + final Configuration conf) { + super(nodeManager, conf); + this.nodeManager = nodeManager; + this.conf = conf; + heavyNodeCriteria = conf.getInt( + ScmConfigKeys.OZONE_DATANODE_MAX_PIPELINE_ENGAGEMENT, + ScmConfigKeys.OZONE_DATANODE_MAX_PIPELINE_ENGAGEMENT_DEFAULT); + } + + /** + * Returns true if this node meets the criteria. + * + * @param datanodeDetails DatanodeDetails + * @return true if we have enough space. + */ + @VisibleForTesting + boolean meetCriteria(DatanodeDetails datanodeDetails, + long heavyNodeLimit) { + return (nodeManager.getPipelinesCount(datanodeDetails) <= heavyNodeLimit); + } + + /** + * Filter out viable nodes based on + * 1. nodes that are healthy + * 2. nodes that are not too heavily engaged in other pipelines + * + * @param excludedNodes - excluded nodes + * @param nodesRequired - number of datanodes required. + * @return a list of viable nodes + * @throws SCMException when viable nodes are not enough in numbers + */ + List<DatanodeDetails> filterViableNodes( + List<DatanodeDetails> excludedNodes, int nodesRequired) + throws SCMException { + // get nodes in HEALTHY state + List<DatanodeDetails> healthyNodes = + nodeManager.getNodes(HddsProtos.NodeState.HEALTHY); + if (excludedNodes != null) { + healthyNodes.removeAll(excludedNodes); + } + String msg; + if (healthyNodes.size() == 0) { + msg = "No healthy node found to allocate container."; + LOG.error(msg); + throw new SCMException(msg, SCMException.ResultCodes + .FAILED_TO_FIND_HEALTHY_NODES); + } + + if (healthyNodes.size() < nodesRequired) { + msg = String.format("Not enough healthy nodes to allocate container. %d " Review comment: container -> pipeline ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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