org.apache.hadoop.hdfs.server.namenode.FSImagePreTransactionalStorageInspector Maven / Gradle / Ivy
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* 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.hdfs.server.namenode;
import java.io.DataInputStream;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeDirType;
import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeFile;
import org.apache.hadoop.io.IOUtils;
/**
* Inspects an FSImage storage directory in the "old" (pre-HDFS-1073) format.
* This format has the following data files:
* - fsimage
* - fsimage.ckpt (when checkpoint is being uploaded)
* - edits
* - edits.new (when logs are "rolled")
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
class FSImagePreTransactionalStorageInspector extends FSImageStorageInspector {
private static final Logger LOG =
LoggerFactory.getLogger(FSImagePreTransactionalStorageInspector.class);
/* Flag if there is at least one storage dir that doesn't contain the newest
* fstime */
private boolean hasOutOfDateStorageDirs = false;
/* Flag set false if there are any "previous" directories found */
private boolean isUpgradeFinalized = true;
private boolean needToSaveAfterRecovery = false;
// Track the name and edits dir with the latest times
private long latestNameCheckpointTime = Long.MIN_VALUE;
private long latestEditsCheckpointTime = Long.MIN_VALUE;
private StorageDirectory latestNameSD = null;
private StorageDirectory latestEditsSD = null;
/** Set to determine if all of storageDirectories share the same checkpoint */
final Set checkpointTimes = new HashSet();
private final List imageDirs = new ArrayList();
private final List editsDirs = new ArrayList();
@Override
void inspectDirectory(StorageDirectory sd) throws IOException {
// Was the file just formatted?
if (!sd.getVersionFile().exists()) {
hasOutOfDateStorageDirs = true;
return;
}
boolean imageExists = false;
boolean editsExists = false;
// Determine if sd is image, edits or both
if (sd.getStorageDirType().isOfType(NameNodeDirType.IMAGE)) {
imageExists = NNStorage.getStorageFile(sd, NameNodeFile.IMAGE).exists();
imageDirs.add(sd.getRoot().getCanonicalPath());
}
if (sd.getStorageDirType().isOfType(NameNodeDirType.EDITS)) {
editsExists = NNStorage.getStorageFile(sd, NameNodeFile.EDITS).exists();
editsDirs.add(sd.getRoot().getCanonicalPath());
}
long checkpointTime = readCheckpointTime(sd);
checkpointTimes.add(checkpointTime);
if (sd.getStorageDirType().isOfType(NameNodeDirType.IMAGE) &&
(latestNameCheckpointTime < checkpointTime) && imageExists) {
latestNameCheckpointTime = checkpointTime;
latestNameSD = sd;
}
if (sd.getStorageDirType().isOfType(NameNodeDirType.EDITS) &&
(latestEditsCheckpointTime < checkpointTime) && editsExists) {
latestEditsCheckpointTime = checkpointTime;
latestEditsSD = sd;
}
// check that we have a valid, non-default checkpointTime
if (checkpointTime <= 0L)
hasOutOfDateStorageDirs = true;
// set finalized flag
isUpgradeFinalized = isUpgradeFinalized && !sd.getPreviousDir().exists();
}
/**
* Determine the checkpoint time of the specified StorageDirectory
*
* @param sd StorageDirectory to check
* @return If file exists and can be read, last checkpoint time. If not, 0L.
* @throws IOException On errors processing file pointed to by sd
*/
static long readCheckpointTime(StorageDirectory sd) throws IOException {
File timeFile = NNStorage.getStorageFile(sd, NameNodeFile.TIME);
long timeStamp = 0L;
if (timeFile.exists() && FileUtil.canRead(timeFile)) {
DataInputStream in = new DataInputStream(
Files.newInputStream(timeFile.toPath()));
try {
timeStamp = in.readLong();
in.close();
in = null;
} finally {
IOUtils.cleanupWithLogger(LOG, in);
}
}
return timeStamp;
}
@Override
boolean isUpgradeFinalized() {
return isUpgradeFinalized;
}
@Override
List getLatestImages() throws IOException {
// We should have at least one image and one edits dirs
if (latestNameSD == null)
throw new IOException("Image file is not found in " + imageDirs);
if (latestEditsSD == null)
throw new IOException("Edits file is not found in " + editsDirs);
// Make sure we are loading image and edits from same checkpoint
if (latestNameCheckpointTime > latestEditsCheckpointTime
&& latestNameSD != latestEditsSD
&& latestNameSD.getStorageDirType() == NameNodeDirType.IMAGE
&& latestEditsSD.getStorageDirType() == NameNodeDirType.EDITS) {
// This is a rare failure when NN has image-only and edits-only
// storage directories, and fails right after saving images,
// in some of the storage directories, but before purging edits.
// See -NOTE- in saveNamespace().
LOG.error("This is a rare failure scenario!!!");
LOG.error("Image checkpoint time " + latestNameCheckpointTime +
" > edits checkpoint time " + latestEditsCheckpointTime);
LOG.error("Name-node will treat the image as the latest state of " +
"the namespace. Old edits will be discarded.");
} else if (latestNameCheckpointTime != latestEditsCheckpointTime) {
throw new IOException("Inconsistent storage detected, " +
"image and edits checkpoint times do not match. " +
"image checkpoint time = " + latestNameCheckpointTime +
"edits checkpoint time = " + latestEditsCheckpointTime);
}
needToSaveAfterRecovery = doRecovery();
FSImageFile file = new FSImageFile(latestNameSD,
NNStorage.getStorageFile(latestNameSD, NameNodeFile.IMAGE),
HdfsServerConstants.INVALID_TXID);
LinkedList ret = new LinkedList();
ret.add(file);
return ret;
}
@Override
boolean needToSave() {
return hasOutOfDateStorageDirs ||
checkpointTimes.size() != 1 ||
latestNameCheckpointTime > latestEditsCheckpointTime ||
needToSaveAfterRecovery;
}
boolean doRecovery() throws IOException {
LOG.debug(
"Performing recovery in "+ latestNameSD + " and " + latestEditsSD);
boolean needToSave = false;
File curFile =
NNStorage.getStorageFile(latestNameSD, NameNodeFile.IMAGE);
File ckptFile =
NNStorage.getStorageFile(latestNameSD, NameNodeFile.IMAGE_NEW);
//
// If we were in the midst of a checkpoint
//
if (ckptFile.exists()) {
needToSave = true;
if (NNStorage.getStorageFile(latestEditsSD, NameNodeFile.EDITS_NEW)
.exists()) {
//
// checkpointing migth have uploaded a new
// merged image, but we discard it here because we are
// not sure whether the entire merged image was uploaded
// before the namenode crashed.
//
if (!ckptFile.delete()) {
throw new IOException("Unable to delete " + ckptFile);
}
} else {
//
// checkpointing was in progress when the namenode
// shutdown. The fsimage.ckpt was created and the edits.new
// file was moved to edits. We complete that checkpoint by
// moving fsimage.new to fsimage. There is no need to
// update the fstime file here. renameTo fails on Windows
// if the destination file already exists.
//
if (!ckptFile.renameTo(curFile)) {
if (!curFile.delete())
LOG.warn("Unable to delete dir " + curFile + " before rename");
if (!ckptFile.renameTo(curFile)) {
throw new IOException("Unable to rename " + ckptFile +
" to " + curFile);
}
}
}
}
return needToSave;
}
/**
* @return a list with the paths to EDITS and EDITS_NEW (if it exists)
* in a given storage directory.
*/
static List getEditsInStorageDir(StorageDirectory sd) {
ArrayList files = new ArrayList();
File edits = NNStorage.getStorageFile(sd, NameNodeFile.EDITS);
assert edits.exists() : "Expected edits file at " + edits;
files.add(edits);
File editsNew = NNStorage.getStorageFile(sd, NameNodeFile.EDITS_NEW);
if (editsNew.exists()) {
files.add(editsNew);
}
return files;
}
private List getLatestEditsFiles() {
if (latestNameCheckpointTime > latestEditsCheckpointTime) {
// the image is already current, discard edits
LOG.debug(
"Name checkpoint time is newer than edits, not loading edits.");
return Collections.emptyList();
}
return getEditsInStorageDir(latestEditsSD);
}
@Override
long getMaxSeenTxId() {
return 0L;
}
static Iterable getEditLogStreams(NNStorage storage)
throws IOException {
FSImagePreTransactionalStorageInspector inspector
= new FSImagePreTransactionalStorageInspector();
storage.inspectStorageDirs(inspector);
List editStreams = new ArrayList();
for (File f : inspector.getLatestEditsFiles()) {
editStreams.add(new EditLogFileInputStream(f));
}
return editStreams;
}
}