TestNodeCount.java
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上传日期:2018-01-08
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- package org.apache.hadoop.hdfs.server.namenode;
- import java.util.Collection;
- import java.util.Iterator;
- import org.apache.hadoop.conf.Configuration;
- import org.apache.hadoop.fs.FileSystem;
- import org.apache.hadoop.fs.Path;
- import org.apache.hadoop.hdfs.DFSTestUtil;
- import org.apache.hadoop.hdfs.MiniDFSCluster;
- import org.apache.hadoop.hdfs.MiniDFSCluster.DataNodeProperties;
- import org.apache.hadoop.hdfs.protocol.Block;
- import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.NumberReplicas;
- import junit.framework.TestCase;
- /**
- * Test if live nodes count per node is correct
- * so NN makes right decision for under/over-replicated blocks
- */
- public class TestNodeCount extends TestCase {
- public void testNodeCount() throws Exception {
- // start a mini dfs cluster of 2 nodes
- final Configuration conf = new Configuration();
- final short REPLICATION_FACTOR = (short)2;
- final MiniDFSCluster cluster =
- new MiniDFSCluster(conf, REPLICATION_FACTOR, true, null);
- try {
- final FSNamesystem namesystem = cluster.getNameNode().namesystem;
- final FileSystem fs = cluster.getFileSystem();
-
- // populate the cluster with a one block file
- final Path FILE_PATH = new Path("/testfile");
- DFSTestUtil.createFile(fs, FILE_PATH, 1L, REPLICATION_FACTOR, 1L);
- DFSTestUtil.waitReplication(fs, FILE_PATH, REPLICATION_FACTOR);
- Block block = DFSTestUtil.getFirstBlock(fs, FILE_PATH);
- // keep a copy of all datanode descriptor
- DatanodeDescriptor[] datanodes = (DatanodeDescriptor[])
- namesystem.heartbeats.toArray(new DatanodeDescriptor[REPLICATION_FACTOR]);
-
- // start two new nodes
- cluster.startDataNodes(conf, 2, true, null, null);
- cluster.waitActive();
-
- // bring down first datanode
- DatanodeDescriptor datanode = datanodes[0];
- DataNodeProperties dnprop = cluster.stopDataNode(datanode.getName());
- // make sure that NN detects that the datanode is down
- synchronized (namesystem.heartbeats) {
- datanode.setLastUpdate(0); // mark it dead
- namesystem.heartbeatCheck();
- }
- // the block will be replicated
- DFSTestUtil.waitReplication(fs, FILE_PATH, REPLICATION_FACTOR);
- // restart the first datanode
- cluster.restartDataNode(dnprop);
- cluster.waitActive();
-
- // check if excessive replica is detected
- NumberReplicas num = null;
- do {
- synchronized (namesystem) {
- num = namesystem.countNodes(block);
- }
- } while (num.excessReplicas() == 0);
-
- // find out a non-excess node
- Iterator<DatanodeDescriptor> iter = namesystem.blocksMap.nodeIterator(block);
- DatanodeDescriptor nonExcessDN = null;
- while (iter.hasNext()) {
- DatanodeDescriptor dn = iter.next();
- Collection<Block> blocks = namesystem.excessReplicateMap.get(dn.getStorageID());
- if (blocks == null || !blocks.contains(block) ) {
- nonExcessDN = dn;
- break;
- }
- }
- assertTrue(nonExcessDN!=null);
-
- // bring down non excessive datanode
- dnprop = cluster.stopDataNode(nonExcessDN.getName());
- // make sure that NN detects that the datanode is down
- synchronized (namesystem.heartbeats) {
- nonExcessDN.setLastUpdate(0); // mark it dead
- namesystem.heartbeatCheck();
- }
-
- // The block should be replicated
- do {
- num = namesystem.countNodes(block);
- } while (num.liveReplicas() != REPLICATION_FACTOR);
-
- // restart the first datanode
- cluster.restartDataNode(dnprop);
- cluster.waitActive();
-
- // check if excessive replica is detected
- do {
- num = namesystem.countNodes(block);
- } while (num.excessReplicas() == 2);
- } finally {
- cluster.shutdown();
- }
- }
- }