update per comments

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/scm/net/InnerNodeImpl.java

@@ -301,7 +301,7 @@ public Node getLeaf(int leafIndex) {
    *
    *   Input:
    *   leafIndex = 2
-   *   excludedScope = /dc2
+   *   excludedScope = /dc2/rack2
    *   excludedNodes = {/dc1/rack1/n1}
    *   ancestorGen = 1
    *

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/scm/net/NetUtils.java

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hdds.scm.net;
 
+import org.apache.commons.collections.CollectionUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -76,9 +77,8 @@ public static int locationToDepth(String location) {
   public static void removeDuplicate(NetworkTopology topology,
       Collection<Node> mutableExcludedNodes, List<String> mutableExcludedScopes,
       int ancestorGen) {
-    if (mutableExcludedNodes == null || mutableExcludedNodes.size() == 0 ||
-        mutableExcludedScopes == null || mutableExcludedScopes.size() == 0 ||
-        topology == null) {
+    if (CollectionUtils.isEmpty(mutableExcludedNodes) ||
+        CollectionUtils.isEmpty(mutableExcludedScopes) || topology == null) {
       return;
     }
 
@@ -114,7 +114,7 @@ public static void removeDuplicate(NetworkTopology topology,
    */
   public static void removeOutscope(Collection<Node> mutableExcludedNodes,
       String scope) {
-    if (mutableExcludedNodes == null || scope == null) {
+    if (CollectionUtils.isEmpty(mutableExcludedNodes) || scope == null) {
       return;
     }
     synchronized (mutableExcludedNodes) {
@@ -139,7 +139,7 @@ public static void removeOutscope(Collection<Node> mutableExcludedNodes,
   public static List<Node> getAncestorList(NetworkTopology topology,
       Collection<Node> nodes, int generation) {
     List<Node> ancestorList = new ArrayList<>();
-    if (topology == null ||nodes == null || nodes.size() == 0 ||
+    if (topology == null || CollectionUtils.isEmpty(nodes) ||
         generation == 0) {
       return ancestorList;
     }

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/scm/net/NetworkTopology.java

@@ -39,15 +39,13 @@ public InvalidTopologyException(String msg) {
    */
   void add(Node node);
 
-
   /**
    * Remove a node from the network topology. This will be called when a
    * existing datanode is removed from the system.
    * @param node node to be removed; cannot be null
    */
   void remove(Node node);
 
-
   /**
    * Check if the tree already contains node <i>node</i>.
    * @param node a node
@@ -68,7 +66,6 @@ public InvalidTopologyException(String msg) {
    */
   boolean isSameAncestor(Node node1, Node node2, int ancestorGen);
 
-
   /**
    * Get the ancestor for node on generation <i>ancestorGen</i>.
    *
@@ -160,26 +157,6 @@ public InvalidTopologyException(String msg) {
   Node chooseRandom(String scope, Collection<Node> excludedNodes,
       int ancestorGen);
 
-
-  /**
-   * Randomly choose a leaf node.
-   *
-   * @param scope range from which a node will be chosen, cannot start with ~
-   * @param excludedNodes nodes to be excluded
-   * @param excludedScopes excluded node ranges. Cannot start with ~
-   * @param ancestorGen matters when excludeNodes is not null. It means the
-   * ancestor generation that's not allowed to share between chosen node and the
-   * excludedNodes. For example, if ancestorGen is 1, means chosen node
-   * cannot share the same parent with excludeNodes. If value is 2, cannot
-   * share the same grand parent, and so on. If ancestorGen is 0, then no
-   * effect.
-   *
-   * @return the chosen node
-   */
-  Node chooseRandom(String scope, List<String>  excludedScopes,
-      Collection<Node> excludedNodes, int ancestorGen);
-
-
   /**
    * Randomly choose one node from <i>scope</i>, share the same generation
    * ancestor with <i>affinityNode</i>, and exclude nodes in

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/scm/net/NetworkTopologyImpl.java

@@ -20,6 +20,7 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
+import org.apache.commons.collections.CollectionUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -365,27 +366,6 @@ public Node chooseRandom(String scope, Collection<Node> excludedNodes,
     }
   }
 
-  /**
-   * Randomly choose a leaf node.
-   *
-   * @param scope range from which a node will be chosen, cannot start with ~
-   * @param excludedNodes nodes to be excluded
-   * @param excludedScopes excluded node ranges. Cannot start with ~
-   * @param ancestorGen matters when excludeNodes is not null. It means the
-   * ancestor generation that's not allowed to share between chosen node and the
-   * excludedNodes. For example, if ancestorGen is 1, means chosen node
-   * cannot share the same parent with excludeNodes. If value is 2, cannot
-   * share the same grand parent, and so on. If ancestorGen is 0, then no
-   * effect.
-   *
-   * @return the chosen node
-   */
-  public Node chooseRandom(String scope, List<String> excludedScopes,
-      Collection<Node> excludedNodes, int ancestorGen) {
-    return chooseRandom(scope, excludedScopes, excludedNodes, null,
-        ancestorGen);
-  }
-
   /**
    * Randomly choose one leaf node from <i>scope</i>, share the same generation
    * ancestor with <i>affinityNode</i>, and exclude nodes in
@@ -784,7 +764,7 @@ private void checkScope(String scope) {
   }
 
   private void checkExcludedScopes(List<String> excludedScopes) {
-    if (excludedScopes != null && excludedScopes.size() > 0) {
+    if (!CollectionUtils.isEmpty(excludedScopes)) {
       excludedScopes.stream().forEach(scope -> {
         if (scope.startsWith(SCOPE_REVERSE_STR)) {
           throw new IllegalArgumentException("excludedScope " + scope +

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/placement/algorithms/SCMContainerPlacementMetrics.java

@@ -37,7 +37,7 @@ public class SCMContainerPlacementMetrics implements MetricsSource {
   public static final String SOURCE_NAME =
       SCMContainerPlacementMetrics.class.getSimpleName();
   private static final MetricsInfo RECORD_INFO = Interns.info(SOURCE_NAME,
-      "SCM Placement Metrics");
+      "SCM Container Placement Metrics");
   private static MetricsRegistry registry;
 
   // total datanode allocation request count
@@ -55,27 +55,23 @@ public SCMContainerPlacementMetrics() {
   public static SCMContainerPlacementMetrics create() {
     MetricsSystem ms = DefaultMetricsSystem.instance();
     registry = new MetricsRegistry(RECORD_INFO);
-    return ms.register(SOURCE_NAME, "SCM Placement Metrics",
+    return ms.register(SOURCE_NAME, "SCM Container Placement Metrics",
         new SCMContainerPlacementMetrics());
   }
 
   public void incrDatanodeRequestCount(long count) {
-    System.out.println("request + 1");
     this.datanodeRequestCount.incr(count);
   }
 
   public void incrDatanodeChooseSuccessCount() {
-    System.out.println("success + 1");
     this.datanodeChooseSuccessCount.incr(1);
   }
 
   public void incrDatanodeChooseFallbackCount() {
-    System.out.println("fallback + 1");
     this.datanodeChooseFallbackCount.incr(1);
   }
 
   public void incrDatanodeChooseAttemptCount() {
-    System.out.println("attempt + 1");
     this.datanodeChooseAttemptCount.incr(1);
   }
 

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/placement/algorithms/SCMContainerPlacementRackAware.java

@@ -242,22 +242,15 @@ private Node chooseNode(List<Node> excludedNodes, Node affinityNode,
       long sizeRequired) throws SCMException {
     int ancestorGen = RACK_LEVEL;
     int maxRetry = MAX_RETRY;
-<<<<<<< HEAD
-    List<Node> excludedNodesForCapacity = null;
+    List<String> excludedNodesForCapacity = null;
     boolean isFallbacked = false;
     while(true) {
-      Node node = networkTopology.chooseRandom(NetConstants.ROOT, null,
-          excludedNodes, affinityNode, ancestorGen);
       metrics.incrDatanodeChooseAttemptCount();
-=======
-    List<String> excludedNodesForCapacity = null;
-    while(true) {
       Node node = networkTopology.chooseRandom(NetConstants.ROOT,
           excludedNodesForCapacity, excludedNodes, affinityNode, ancestorGen);
->>>>>>> HDDS-1879. Support multiple excluded scopes when choosing datanodes in NetworkTopology.
       if (node == null) {
         // cannot find the node which meets all constrains
-        LOG.warn("Failed to find the datanode. excludedNodes:" +
+        LOG.warn("Failed to find the datanode for container. excludedNodes:" +
             (excludedNodes == null ? "" : excludedNodes.toString()) +
             ", affinityNode:" +
             (affinityNode == null ? "" : affinityNode.getNetworkFullPath()));
@@ -279,18 +272,12 @@ private Node chooseNode(List<Node> excludedNodes, Node affinityNode,
             " excludedNodes and affinityNode constrains.", null);
       }
       if (hasEnoughSpace((DatanodeDetails)node, sizeRequired)) {
-        LOG.warn("Datanode {} is chosen. Required size is {}",
+        LOG.debug("Datanode {} is chosen for container. Required size is {}",
             node.toString(), sizeRequired);
-<<<<<<< HEAD
-        if (excludedNodes != null && excludedNodesForCapacity != null) {
-          excludedNodes.removeAll(excludedNodesForCapacity);
-        }
         metrics.incrDatanodeChooseSuccessCount();
         if (isFallbacked) {
           metrics.incrDatanodeChooseFallbackCount();
         }
-=======
->>>>>>> HDDS-1879. Support multiple excluded scopes when choosing datanodes in NetworkTopology.
         return node;
       } else {
         maxRetry--;