[GitHub] [ozone] lokeshj1703 commented on a change in pull request #2278: HDDS-4926. Support start/stop for container balancer via command line

[GitBox <gi...@apache.org>]

lokeshj1703 commented on a change in pull request #2278:
URL: https://github.com/apache/ozone/pull/2278#discussion_r645652848



##########
File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/balancer/ContainerBalancer.java
##########
@@ -111,27 +112,42 @@ public boolean start(ContainerBalancerConfiguration balancerConfiguration) {
 
     ozoneConfiguration = new OzoneConfiguration();
     this.config = balancerConfiguration;
+    this.idleIteration = config.getIdleIteration();
     this.threshold = config.getThreshold();
     this.maxDatanodesToBalance = config.getMaxDatanodesToBalance();
     this.maxSizeToMove = config.getMaxSizeToMove();
     this.unBalancedNodes = new ArrayList<>();
-
     LOG.info("Starting Container Balancer...{}", this);
-    balance();
+    //we should start a new balancer thread async
+    //and response to cli as soon as possible
+
+
+    //this is a temporary implementation

Review comment:
       NIT: Can we specify TODO: in the comment?

##########
File path: hadoop-hdds/tools/src/main/java/org/apache/hadoop/hdds/scm/cli/ContainerBalancerStartSubcommand.java
##########
@@ -0,0 +1,64 @@
+/*
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.cli;
+
+import org.apache.hadoop.hdds.cli.HddsVersionProvider;
+import org.apache.hadoop.hdds.scm.client.ScmClient;
+import picocli.CommandLine;
+import picocli.CommandLine.Command;
+
+import java.io.IOException;
+
+/**
+ * Handler to start container balancer.
+ */
+@Command(
+    name = "start",
+    description = "Start ContainerBalancer",
+    mixinStandardHelpOptions = true,
+    versionProvider = HddsVersionProvider.class)
+public class ContainerBalancerStartSubcommand extends ScmSubcommand {
+
+  @CommandLine.Option(names = {"-t", "--threshold"},
+      description = "Threshold target whether the cluster is balanced")
+  private double threshold;

Review comment:
       We can specify all these options as Optional<Double> etc. The SCMClient could also use Optional as parameter.

##########
File path: hadoop-hdds/interface-admin/src/main/proto/ScmAdminProtocol.proto
##########
@@ -445,6 +454,32 @@ message GetContainerTokenResponseProto {
   required TokenProto token = 1;
 }
 
+message StartContainerBalancerRequestProto {
+  optional string traceID = 1;
+  required double threshold = 2;

Review comment:
       I think @ChenSammi is pointing out that since all these fields do not have default values they should be optional.

##########
File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/balancer/ContainerBalancer.java
##########
@@ -323,8 +344,22 @@ public static double calculateUtilization(
    * Stops ContainerBalancer.
    */
   public void stop() {

Review comment:
       We will need to make start and stop synchronized. In a race condition it is possible for balancerRunning to be set as true but thread may not be running.

##########
File path: hadoop-hdds/server-scm/src/test/java/org/apache/hadoop/hdds/scm/container/balancer/TestContainerBalancer.java
##########
@@ -96,11 +97,18 @@ public void setup() {
 
       balancerConfiguration.setThreshold(randomThreshold);
       containerBalancer.start(balancerConfiguration);
+
+      // waiting for balance completed.
+      // this is a temporary implementation for now
+      // modify this after balancer is fully completed

Review comment:
       NIT: Can we add a TODO: in comments?




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