swamirishi commented on code in PR #8477: URL: https://github.com/apache/ozone/pull/8477#discussion_r2132229935
########## hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OMDBCheckpointServletInodeBasedXfer.java: ########## @@ -0,0 +1,365 @@ +/* + * 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.ozone.om; + +import static org.apache.hadoop.hdds.utils.Archiver.*; +import static org.apache.hadoop.ozone.OzoneConsts.*; +import static org.apache.hadoop.ozone.om.OMConfigKeys.OZONE_OM_RATIS_SNAPSHOT_MAX_TOTAL_SST_SIZE_DEFAULT; +import static org.apache.hadoop.ozone.om.OMConfigKeys.OZONE_OM_RATIS_SNAPSHOT_MAX_TOTAL_SST_SIZE_KEY; +import static org.apache.hadoop.ozone.om.snapshot.OmSnapshotUtils.DATA_PREFIX; +import static org.apache.hadoop.ozone.om.snapshot.OmSnapshotUtils.DATA_SUFFIX; + +import java.io.File; +import java.io.IOException; +import java.io.OutputStream; +import java.nio.charset.StandardCharsets; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.time.Duration; +import java.time.Instant; +import java.util.ArrayList; +import java.util.Collection; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Iterator; +import java.util.LinkedHashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.atomic.AtomicLong; +import java.util.stream.Stream; +import javax.servlet.ServletException; +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletResponse; +import org.apache.commons.compress.archivers.ArchiveOutputStream; +import org.apache.commons.compress.archivers.tar.TarArchiveEntry; +import org.apache.commons.io.FileUtils; +import org.apache.commons.io.IOCase; +import org.apache.commons.io.file.PathFilter; +import org.apache.commons.io.filefilter.SuffixFileFilter; +import org.apache.hadoop.hdds.conf.OzoneConfiguration; +import org.apache.hadoop.hdds.recon.ReconConfig; +import org.apache.hadoop.hdds.utils.DBCheckpointServlet; +import org.apache.hadoop.hdds.utils.db.DBCheckpoint; +import org.apache.hadoop.ozone.OzoneConsts; +import org.apache.hadoop.ozone.lock.BootstrapStateHandler; +import org.apache.hadoop.ozone.om.helpers.SnapshotInfo; +import org.apache.hadoop.ozone.om.snapshot.OmSnapshotUtils; +import org.apache.hadoop.security.UserGroupInformation; +import org.apache.ozone.rocksdiff.RocksDBCheckpointDiffer; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Specialized OMDBCheckpointServlet implementation that transfers Ozone Manager + * database checkpoints using inode-based deduplication. + * <p> + * This servlet constructs checkpoint archives by examining file inodes, + * ensuring that files with the same inode (i.e., hardlinks or duplicates) + * are only transferred once. It maintains mappings from inode IDs to file + * paths, manages hardlink information, and enforces snapshot and SST file + * size constraints as needed. + * <p> + * This approach optimizes checkpoint streaming by reducing redundant data + * transfer, especially in environments where RocksDB and snapshotting result + * in multiple hardlinks to the same physical data. + */ +public class OMDBCheckpointServletInodeBasedXfer extends DBCheckpointServlet { + + protected static final Logger LOG = + LoggerFactory.getLogger(OMDBCheckpointServletInodeBasedXfer.class); + private static final long serialVersionUID = 1L; + private static final PathFilter SST_FILE_FILTER = + new SuffixFileFilter(ROCKSDB_SST_SUFFIX, IOCase.INSENSITIVE); + + @Override + public void init() throws ServletException { + OzoneManager om = (OzoneManager) getServletContext() + .getAttribute(OzoneConsts.OM_CONTEXT_ATTRIBUTE); + + if (om == null) { + LOG.error("Unable to initialize OMDBCheckpointServlet. OM is null"); + return; + } + + OzoneConfiguration conf = getConf(); + // Only Ozone Admins and Recon are allowed + Collection<String> allowedUsers = + new LinkedHashSet<>(om.getOmAdminUsernames()); + Collection<String> allowedGroups = om.getOmAdminGroups(); + ReconConfig reconConfig = conf.getObject(ReconConfig.class); + String reconPrincipal = reconConfig.getKerberosPrincipal(); + if (!reconPrincipal.isEmpty()) { + UserGroupInformation ugi = + UserGroupInformation.createRemoteUser(reconPrincipal); + allowedUsers.add(ugi.getShortUserName()); + } + + initialize(om.getMetadataManager().getStore(), + om.getMetrics().getDBCheckpointMetrics(), + om.getAclsEnabled(), + allowedUsers, + allowedGroups, + om.isSpnegoEnabled()); + } + + + protected static Path getMetaDirPath(Path checkpointLocation) { + // This check is done to take care of findbugs else below getParent() + // should not be null. + Path locationParent = checkpointLocation.getParent(); + if (null == locationParent) { + throw new RuntimeException( + "checkpoint location's immediate parent is null."); + } + Path parent = locationParent.getParent(); + if (null == parent) { + throw new RuntimeException( + "checkpoint location's path is invalid and could not be verified."); + } + return parent; + } + + // Returns value of http request parameter. + protected static boolean includeSnapshotData(HttpServletRequest request) { + String includeParam = + request.getParameter(OZONE_DB_CHECKPOINT_INCLUDE_SNAPSHOT_DATA); + return Boolean.parseBoolean(includeParam); + } + + @Override + protected void processMetadataSnapshotRequest(HttpServletRequest request, HttpServletResponse response, + boolean isFormData, DBCheckpoint checkpoint, boolean flush) { + List<String> excludedSstList = new ArrayList<>(); + String[] sstParam = isFormData ? + parseFormDataParameters(request) : request.getParameterValues( + OZONE_DB_CHECKPOINT_REQUEST_TO_EXCLUDE_SST); + Set<String> receivedSstFiles = fetchSstFilesReceived(sstParam); + Path tmpdir = null; + try (BootstrapStateHandler.Lock lock = getBootstrapStateLock().lock()) { + tmpdir = Files.createTempDirectory(getBootstrapTempData().toPath(), + "bootstrap-data-"); + String tarName = "om.data-" + System.currentTimeMillis() + ".tar"; + response.setContentType("application/x-tar"); + response.setHeader("Content-Disposition", "attachment; filename=\"" + tarName + "\""); + Instant start = Instant.now(); + writeDbDataToStream(request, response.getOutputStream(), receivedSstFiles, tmpdir); + Instant end = Instant.now(); + long duration = Duration.between(start, end).toMillis(); + LOG.info("Time taken to write the checkpoint to response output " + + "stream: {} milliseconds", duration); + logSstFileList(excludedSstList, + "Excluded {} SST files from the latest checkpoint{}: {}", 5); + } catch (Exception e){ + LOG.error( + "Unable to process metadata snapshot request. ", e); + response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); + } finally { + try { + if (tmpdir != null) { + FileUtils.deleteDirectory(tmpdir.toFile()); + } + } catch (IOException e) { + LOG.error("unable to delete: " + tmpdir); + } + } + super.processMetadataSnapshotRequest(request, response, isFormData, checkpoint, flush); + } + + + public void writeDbDataToStream(HttpServletRequest request, OutputStream destination, + Set<String> sstFilesToExclude, Path tmpdir) throws IOException, InterruptedException { + DBCheckpoint checkpoint = null; + // Key is the InodeID and the first encountered file path with this inodeID + Map<String, Path> copyFiles = new HashMap<>(); + OzoneManager om = (OzoneManager) getServletContext().getAttribute(OzoneConsts.OM_CONTEXT_ATTRIBUTE); + OMMetadataManager omMetadataManager = om.getMetadataManager(); + boolean includeSnapshotData = includeSnapshotData(request); + AtomicLong maxTotalSstSize = new AtomicLong(getConf().getLong(OZONE_OM_RATIS_SNAPSHOT_MAX_TOTAL_SST_SIZE_KEY, + OZONE_OM_RATIS_SNAPSHOT_MAX_TOTAL_SST_SIZE_DEFAULT)); + + if (!includeSnapshotData) { + maxTotalSstSize.set(Long.MAX_VALUE); + } + + boolean shouldContinue = true; + + Set<Path> allPathsToVisit = new HashSet<>(); + try (ArchiveOutputStream<TarArchiveEntry> archiveOutputStream = tar(destination)) { + if (includeSnapshotData) { + Set<Path> snapshotDbPaths = collectSnapshotPaths(omMetadataManager); + // Process each snapshot db path and write it to archive + for (Path snapshotDbPath : snapshotDbPaths) { + if (!shouldContinue) { + break; + } + shouldContinue = writeDBToArchive(copyFiles, sstFilesToExclude, snapshotDbPath, + maxTotalSstSize, archiveOutputStream, tmpdir); + } + + RocksDBCheckpointDiffer differ = getDbStore().getRocksDBCheckpointDiffer(); + Path sstBackupDir = new File(differ.getSSTBackupDir()).toPath(); + Path compactionLogDir = new File(differ.getCompactionLogDir()).toPath(); + + if (shouldContinue) { + shouldContinue = writeDBToArchive(copyFiles, sstFilesToExclude, sstBackupDir, + maxTotalSstSize, archiveOutputStream, tmpdir); + } + + if (shouldContinue) { + shouldContinue = writeDBToArchive(copyFiles, sstFilesToExclude, compactionLogDir, + maxTotalSstSize, archiveOutputStream, tmpdir); + } + // Add paths of snapshot databases, SST backups, and compaction logs to visit list + allPathsToVisit.addAll(snapshotDbPaths); + allPathsToVisit.add(sstBackupDir); + allPathsToVisit.add(compactionLogDir); + } + + if (shouldContinue) { + // we finished transferring files from snapshot DB's by now and + // this is the last step where we transfer the active om.db contents + checkpoint = getCheckpoint(tmpdir,true); + // unlimited files as we want the Active DB contents to be transferred in a single batch + maxTotalSstSize.set(Long.MAX_VALUE); + Path checkpointDir = checkpoint.getCheckpointLocation(); + writeDBToArchive(copyFiles, sstFilesToExclude, checkpointDir, + maxTotalSstSize, archiveOutputStream, tmpdir); + allPathsToVisit.add(checkpointDir); + generateAndWriteHardlinkFile(checkpointDir, allPathsToVisit, archiveOutputStream); + } + + } catch (Exception e) { + LOG.error("got exception writing to archive " + e); + throw e; + } finally { + cleanupCheckpoint(checkpoint); + } + } + + private static void cleanupCheckpoint(DBCheckpoint checkpoint) { + if (checkpoint != null) { + try { + checkpoint.cleanupCheckpoint(); + } catch (IOException e) { + LOG.error("Error trying to clean checkpoint at {} .", + checkpoint.getCheckpointLocation().toString()); + } + } + } + + /** + * Generates a file containing hardlink information and writes it to the archive. + * + * @param checkpointDir Directory containing the checkpoint + * @param allPathsToVisit Set of all paths to visit for hardlink information + * @param archiveOutputStream Archive output stream + * @throws IOException if an I/O error occurs + */ + private static void generateAndWriteHardlinkFile(Path checkpointDir, Set<Path> allPathsToVisit, + ArchiveOutputStream<TarArchiveEntry> archiveOutputStream) throws IOException { + Path data = Files.createTempFile(DATA_PREFIX, DATA_SUFFIX); + Path metaDirPath = getMetaDirPath(checkpointDir); + int truncateLength = metaDirPath.toString().length() + 1; + StringBuilder sb = new StringBuilder(); + + for (Path path : allPathsToVisit) { + try (Stream<Path> files = Files.walk(path)) { + Iterable<Path> iterable = files::iterator; + Iterator<Path> iterator = iterable.iterator(); + for (; iterator.hasNext();) { + Path p = iterator.next(); + String fileId = OmSnapshotUtils.getInodeAndMtime(p); + String relativePath = p.toString().substring(truncateLength); + sb.append(fileId).append("\t").append(relativePath).append("\n"); + } + } + } + Files.write(data, sb.toString().getBytes(StandardCharsets.UTF_8)); + includeFile(data.toFile(), OmSnapshotManager.OM_HARDLINK_FILE, archiveOutputStream); + } + + /** + * Gets the configuration from the OzoneManager context. + * + * @return OzoneConfiguration instance + */ + private OzoneConfiguration getConf() { + return ((OzoneManager) getServletContext() + .getAttribute(OzoneConsts.OM_CONTEXT_ATTRIBUTE)) + .getConfiguration(); + } + + /** + * Collects paths to all snapshot databases. + * + * @param omMetadataManager OMMetadataManager instance + * @return Set of paths to snapshot databases + * @throws IOException if an I/O error occurs + */ + Set<Path> collectSnapshotPaths(OMMetadataManager omMetadataManager) throws IOException { + Set<Path> snapshotDbPaths = new HashSet<>(); + SnapshotChainManager snapshotChainManager = new SnapshotChainManager(omMetadataManager); + for (SnapshotChainInfo snapInfo : snapshotChainManager.getGlobalSnapshotChain().values()) { + String snapshotDir = + OmSnapshotManager.getSnapshotPath(getConf(), SnapshotInfo.getCheckpointDirName(snapInfo.getSnapshotId())); + Path path = Paths.get(snapshotDir); + snapshotDbPaths.add(path); + } + return snapshotDbPaths; + } + + /** + * Writes database files to the archive, handling deduplication based on inode IDs. + * + * @param copyFiles Map of inode IDs to file paths that have already been processed + * @param sstFilesToExclude Set of SST file IDs to exclude from the archive + * @param dbDir Directory containing database files to archive + * @param maxTotalSstSize Maximum total size of SST files to include + * @param archiveOutputStream Archive output stream + * @param tmpDir Temporary directory for processing + * @return true if processing should continue, false if size limit reached + * @throws IOException if an I/O error occurs + */ + boolean writeDBToArchive(Map<String, Path> copyFiles, + Set<String> sstFilesToExclude, Path dbDir, AtomicLong maxTotalSstSize, + ArchiveOutputStream<TarArchiveEntry> archiveOutputStream, Path tmpDir) throws IOException { Review Comment: ```suggestion ArchiveOutputStream<TarArchiveEntry> archiveOutputStream, Path tmpDir, Map<String, String> hardLinkFileMap) throws IOException { ``` -- This is an automated message from the Apache Git Service. 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