/// <summary>Check whether the secondary name-node can be started.</summary>
/// <exception cref="System.IO.IOException"/>
private bool CanStartSecondaryNode(Configuration conf)
{
// Using full name allows us not to have to add deprecation tag to
// entire source file.
SecondaryNameNode sn = null;
try
{
sn = new SecondaryNameNode(conf);
}
catch (IOException e)
{
if (e is BindException)
{
return(false);
}
throw;
}
finally
{
if (sn != null)
{
sn.Shutdown();
}
}
return(true);
}
public virtual void TestCheckpointWithSNN()
{
MiniDFSCluster cluster = null;
DistributedFileSystem dfs = null;
SecondaryNameNode snn = null;
try
{
Configuration conf = new HdfsConfiguration();
cluster = new MiniDFSCluster.Builder(conf).Build();
cluster.WaitActive();
conf.Set(DFSConfigKeys.DfsNamenodeSecondaryHttpAddressKey, "0.0.0.0:0");
snn = new SecondaryNameNode(conf);
dfs = cluster.GetFileSystem();
dfs.Mkdirs(new Path("/test/foo"));
snn.DoCheckpoint();
//start rolling upgrade
dfs.SetSafeMode(HdfsConstants.SafeModeAction.SafemodeEnter);
dfs.RollingUpgrade(HdfsConstants.RollingUpgradeAction.Prepare);
dfs.SetSafeMode(HdfsConstants.SafeModeAction.SafemodeLeave);
dfs.Mkdirs(new Path("/test/bar"));
// do checkpoint in SNN again
snn.DoCheckpoint();
}
finally
{
IOUtils.Cleanup(null, dfs);
if (snn != null)
{
snn.Shutdown();
}
if (cluster != null)
{
cluster.Shutdown();
}
}
}
public virtual void TestCheckpoint()
{
MiniDFSCluster cluster = null;
SecondaryNameNode secondary = null;
try
{
cluster = new MiniDFSCluster.Builder(conf).Build();
cluster.WaitActive();
secondary = new SecondaryNameNode(conf);
SnapshotManager nnSnapshotManager = cluster.GetNamesystem().GetSnapshotManager();
SnapshotManager secondarySnapshotManager = secondary.GetFSNamesystem().GetSnapshotManager
();
FileSystem fs = cluster.GetFileSystem();
HdfsAdmin admin = new HdfsAdmin(FileSystem.GetDefaultUri(conf), conf);
NUnit.Framework.Assert.AreEqual(0, nnSnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(0, nnSnapshotManager.GetNumSnapshottableDirs());
NUnit.Framework.Assert.AreEqual(0, secondarySnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(0, secondarySnapshotManager.GetNumSnapshottableDirs
());
// 1. Create a snapshottable directory foo on the NN.
fs.Mkdirs(TestPath);
admin.AllowSnapshot(TestPath);
NUnit.Framework.Assert.AreEqual(0, nnSnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(1, nnSnapshotManager.GetNumSnapshottableDirs());
// 2. Create a snapshot of the dir foo. This will be referenced both in
// the SnapshotManager as well as in the file system tree. The snapshot
// count will go up to 1.
Path snapshotPath = fs.CreateSnapshot(TestPath);
NUnit.Framework.Assert.AreEqual(1, nnSnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(1, nnSnapshotManager.GetNumSnapshottableDirs());
// 3. Start up a 2NN and have it do a checkpoint. It will have foo and its
// snapshot in its list of snapshottable dirs referenced from the
// SnapshotManager, as well as in the file system tree.
secondary.DoCheckpoint();
NUnit.Framework.Assert.AreEqual(1, secondarySnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(1, secondarySnapshotManager.GetNumSnapshottableDirs
());
// 4. Disallow snapshots on and delete foo on the NN. The snapshot count
// will go down to 0 and the snapshottable dir will be removed from the fs
// tree.
fs.DeleteSnapshot(TestPath, snapshotPath.GetName());
admin.DisallowSnapshot(TestPath);
NUnit.Framework.Assert.AreEqual(0, nnSnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(0, nnSnapshotManager.GetNumSnapshottableDirs());
// 5. Have the NN do a saveNamespace, writing out a new fsimage with
// snapshot count 0.
NameNodeAdapter.EnterSafeMode(cluster.GetNameNode(), false);
NameNodeAdapter.SaveNamespace(cluster.GetNameNode());
NameNodeAdapter.LeaveSafeMode(cluster.GetNameNode());
// 6. Have the still-running 2NN do a checkpoint. It will notice that the
// fsimage has changed on the NN and redownload/reload from that image.
// This will replace all INodes in the file system tree as well as reset
// the snapshot counter to 0 in the SnapshotManager. However, it will not
// clear the list of snapshottable dirs referenced from the
// SnapshotManager. When it writes out an fsimage, the 2NN will write out
// 0 for the snapshot count, but still serialize the snapshottable dir
// referenced in the SnapshotManager even though it no longer appears in
// the file system tree. The NN will not be able to start up with this.
secondary.DoCheckpoint();
NUnit.Framework.Assert.AreEqual(0, secondarySnapshotManager.GetNumSnapshots());
NUnit.Framework.Assert.AreEqual(0, secondarySnapshotManager.GetNumSnapshottableDirs
());
}
finally
{
if (cluster != null)
{
cluster.Shutdown();
}
if (secondary != null)
{
secondary.Shutdown();
}
}
}