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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.hbase.master.snapshot;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ThreadPoolExecutor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.MetaTableAccessor;
import org.apache.hadoop.hbase.errorhandling.ForeignException;
import org.apache.hadoop.hbase.executor.ExecutorService;
import org.apache.hadoop.hbase.master.AssignmentManager;
import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
import org.apache.hadoop.hbase.master.MasterFileSystem;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.MetricsMaster;
import org.apache.hadoop.hbase.master.SnapshotSentinel;
import org.apache.hadoop.hbase.master.cleaner.HFileCleaner;
import org.apache.hadoop.hbase.master.cleaner.HFileLinkCleaner;
import org.apache.hadoop.hbase.procedure.MasterProcedureManager;
import org.apache.hadoop.hbase.procedure.Procedure;
import org.apache.hadoop.hbase.procedure.ProcedureCoordinator;
import org.apache.hadoop.hbase.procedure.ProcedureCoordinatorRpcs;
import org.apache.hadoop.hbase.procedure.ZKProcedureCoordinatorRpcs;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.NameStringPair;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ProcedureDescription;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription.Type;
import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
import org.apache.hadoop.hbase.snapshot.ClientSnapshotDescriptionUtils;
import org.apache.hadoop.hbase.snapshot.HBaseSnapshotException;
import org.apache.hadoop.hbase.snapshot.RestoreSnapshotException;
import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
import org.apache.hadoop.hbase.snapshot.SnapshotCreationException;
import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
import org.apache.hadoop.hbase.snapshot.SnapshotDoesNotExistException;
import org.apache.hadoop.hbase.snapshot.SnapshotExistsException;
import org.apache.hadoop.hbase.snapshot.SnapshotManifest;
import org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil;
import org.apache.hadoop.hbase.snapshot.TablePartiallyOpenException;
import org.apache.hadoop.hbase.snapshot.UnknownSnapshotException;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.FSUtils;
import org.apache.zookeeper.KeeperException;
/**
* This class manages the procedure of taking and restoring snapshots. There is only one
* SnapshotManager for the master.
*
* The class provides methods for monitoring in-progress snapshot actions.
*
* Note: Currently there can only be one snapshot being taken at a time over the cluster. This is a
* simplification in the current implementation.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
@InterfaceStability.Unstable
public class SnapshotManager extends MasterProcedureManager implements Stoppable {
private static final Log LOG = LogFactory.getLog(SnapshotManager.class);
/** By default, check to see if the snapshot is complete every WAKE MILLIS (ms) */
private static final int SNAPSHOT_WAKE_MILLIS_DEFAULT = 500;
/**
* Wait time before removing a finished sentinel from the in-progress map
*
* NOTE: This is used as a safety auto cleanup.
* The snapshot and restore handlers map entries are removed when a user asks if a snapshot or
* restore is completed. This operation is part of the HBaseAdmin snapshot/restore API flow.
* In case something fails on the client side and the snapshot/restore state is not reclaimed
* after a default timeout, the entry is removed from the in-progress map.
* At this point, if the user asks for the snapshot/restore status, the result will be
* snapshot done if exists or failed if it doesn't exists.
*/
private static final int SNAPSHOT_SENTINELS_CLEANUP_TIMEOUT = 60 * 1000;
/** Enable or disable snapshot support */
public static final String HBASE_SNAPSHOT_ENABLED = "hbase.snapshot.enabled";
/**
* Conf key for # of ms elapsed between checks for snapshot errors while waiting for
* completion.
*/
private static final String SNAPSHOT_WAKE_MILLIS_KEY = "hbase.snapshot.master.wakeMillis";
/** By default, check to see if the snapshot is complete (ms) */
private static final int SNAPSHOT_TIMEOUT_MILLIS_DEFAULT = 60000;
/**
* Conf key for # of ms elapsed before injecting a snapshot timeout error when waiting for
* completion.
*/
private static final String SNAPSHOT_TIMEOUT_MILLIS_KEY = "hbase.snapshot.master.timeoutMillis";
/** Name of the operation to use in the controller */
public static final String ONLINE_SNAPSHOT_CONTROLLER_DESCRIPTION = "online-snapshot";
/** Conf key for # of threads used by the SnapshotManager thread pool */
private static final String SNAPSHOT_POOL_THREADS_KEY = "hbase.snapshot.master.threads";
/** number of current operations running on the master */
private static final int SNAPSHOT_POOL_THREADS_DEFAULT = 1;
private boolean stopped;
private MasterServices master; // Needed by TableEventHandlers
private ProcedureCoordinator coordinator;
// Is snapshot feature enabled?
private boolean isSnapshotSupported = false;
// Snapshot handlers map, with table name as key.
// The map is always accessed and modified under the object lock using synchronized.
// snapshotTable() will insert an Handler in the table.
// isSnapshotDone() will remove the handler requested if the operation is finished.
private Map snapshotHandlers =
new HashMap();
// Restore Sentinels map, with table name as key.
// The map is always accessed and modified under the object lock using synchronized.
// restoreSnapshot()/cloneSnapshot() will insert an Handler in the table.
// isRestoreDone() will remove the handler requested if the operation is finished.
private Map restoreHandlers =
new HashMap();
private Path rootDir;
private ExecutorService executorService;
public SnapshotManager() {}
/**
* Fully specify all necessary components of a snapshot manager. Exposed for testing.
* @param master services for the master where the manager is running
* @param coordinator procedure coordinator instance. exposed for testing.
* @param pool HBase ExecutorServcie instance, exposed for testing.
*/
public SnapshotManager(final MasterServices master, final MetricsMaster metricsMaster,
ProcedureCoordinator coordinator, ExecutorService pool)
throws IOException, UnsupportedOperationException {
this.master = master;
this.rootDir = master.getMasterFileSystem().getRootDir();
checkSnapshotSupport(master.getConfiguration(), master.getMasterFileSystem());
this.coordinator = coordinator;
this.executorService = pool;
resetTempDir();
}
/**
* Gets the list of all completed snapshots.
* @return list of SnapshotDescriptions
* @throws IOException File system exception
*/
public List getCompletedSnapshots() throws IOException {
return getCompletedSnapshots(SnapshotDescriptionUtils.getSnapshotsDir(rootDir));
}
/**
* Gets the list of all completed snapshots.
* @param snapshotDir snapshot directory
* @return list of SnapshotDescriptions
* @throws IOException File system exception
*/
private List getCompletedSnapshots(Path snapshotDir) throws IOException {
List snapshotDescs = new ArrayList();
// first create the snapshot root path and check to see if it exists
FileSystem fs = master.getMasterFileSystem().getFileSystem();
if (snapshotDir == null) snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(rootDir);
// if there are no snapshots, return an empty list
if (!fs.exists(snapshotDir)) {
return snapshotDescs;
}
// ignore all the snapshots in progress
FileStatus[] snapshots = fs.listStatus(snapshotDir,
new SnapshotDescriptionUtils.CompletedSnaphotDirectoriesFilter(fs));
// loop through all the completed snapshots
for (FileStatus snapshot : snapshots) {
Path info = new Path(snapshot.getPath(), SnapshotDescriptionUtils.SNAPSHOTINFO_FILE);
// if the snapshot is bad
if (!fs.exists(info)) {
LOG.error("Snapshot information for " + snapshot.getPath() + " doesn't exist");
continue;
}
FSDataInputStream in = null;
try {
in = fs.open(info);
SnapshotDescription desc = SnapshotDescription.parseFrom(in);
snapshotDescs.add(desc);
} catch (IOException e) {
LOG.warn("Found a corrupted snapshot " + snapshot.getPath(), e);
} finally {
if (in != null) {
in.close();
}
}
}
return snapshotDescs;
}
/**
* Cleans up any snapshots in the snapshot/.tmp directory that were left from failed
* snapshot attempts.
*
* @throws IOException if we can't reach the filesystem
*/
void resetTempDir() throws IOException {
// cleanup any existing snapshots.
Path tmpdir = SnapshotDescriptionUtils.getWorkingSnapshotDir(rootDir);
if (master.getMasterFileSystem().getFileSystem().exists(tmpdir)) {
if (!master.getMasterFileSystem().getFileSystem().delete(tmpdir, true)) {
LOG.warn("Couldn't delete working snapshot directory: " + tmpdir);
}
}
}
/**
* Delete the specified snapshot
* @param snapshot
* @throws SnapshotDoesNotExistException If the specified snapshot does not exist.
* @throws IOException For filesystem IOExceptions
*/
public void deleteSnapshot(SnapshotDescription snapshot) throws SnapshotDoesNotExistException, IOException {
// call coproc pre hook
MasterCoprocessorHost cpHost = master.getMasterCoprocessorHost();
if (cpHost != null) {
cpHost.preDeleteSnapshot(snapshot);
}
// check to see if it is completed
if (!isSnapshotCompleted(snapshot)) {
throw new SnapshotDoesNotExistException(snapshot);
}
String snapshotName = snapshot.getName();
LOG.debug("Deleting snapshot: " + snapshotName);
// first create the snapshot description and check to see if it exists
MasterFileSystem fs = master.getMasterFileSystem();
Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshotName, rootDir);
// delete the existing snapshot
if (!fs.getFileSystem().delete(snapshotDir, true)) {
throw new HBaseSnapshotException("Failed to delete snapshot directory: " + snapshotDir);
}
// call coproc post hook
if (cpHost != null) {
cpHost.postDeleteSnapshot(snapshot);
}
}
/**
* Check if the specified snapshot is done
*
* @param expected
* @return true if snapshot is ready to be restored, false if it is still being taken.
* @throws IOException IOException if error from HDFS or RPC
* @throws UnknownSnapshotException if snapshot is invalid or does not exist.
*/
public boolean isSnapshotDone(SnapshotDescription expected) throws IOException {
// check the request to make sure it has a snapshot
if (expected == null) {
throw new UnknownSnapshotException(
"No snapshot name passed in request, can't figure out which snapshot you want to check.");
}
String ssString = ClientSnapshotDescriptionUtils.toString(expected);
// check to see if the sentinel exists,
// and if the task is complete removes it from the in-progress snapshots map.
SnapshotSentinel handler = removeSentinelIfFinished(this.snapshotHandlers, expected);
// stop tracking "abandoned" handlers
cleanupSentinels();
if (handler == null) {
// If there's no handler in the in-progress map, it means one of the following:
// - someone has already requested the snapshot state
// - the requested snapshot was completed long time ago (cleanupSentinels() timeout)
// - the snapshot was never requested
// In those cases returns to the user the "done state" if the snapshots exists on disk,
// otherwise raise an exception saying that the snapshot is not running and doesn't exist.
if (!isSnapshotCompleted(expected)) {
throw new UnknownSnapshotException("Snapshot " + ssString
+ " is not currently running or one of the known completed snapshots.");
}
// was done, return true;
return true;
}
// pass on any failure we find in the sentinel
try {
handler.rethrowExceptionIfFailed();
} catch (ForeignException e) {
// Give some procedure info on an exception.
String status;
Procedure p = coordinator.getProcedure(expected.getName());
if (p != null) {
status = p.getStatus();
} else {
status = expected.getName() + " not found in proclist " + coordinator.getProcedureNames();
}
throw new HBaseSnapshotException("Snapshot " + ssString + " had an error. " + status, e,
expected);
}
// check to see if we are done
if (handler.isFinished()) {
LOG.debug("Snapshot '" + ssString + "' has completed, notifying client.");
return true;
} else if (LOG.isDebugEnabled()) {
LOG.debug("Snapshoting '" + ssString + "' is still in progress!");
}
return false;
}
/**
* Check to see if there is a snapshot in progress with the same name or on the same table.
* Currently we have a limitation only allowing a single snapshot per table at a time. Also we
* don't allow snapshot with the same name.
* @param snapshot description of the snapshot being checked.
* @return true if there is a snapshot in progress with the same name or on the same
* table.
*/
synchronized boolean isTakingSnapshot(final SnapshotDescription snapshot) {
TableName snapshotTable = TableName.valueOf(snapshot.getTable());
if (isTakingSnapshot(snapshotTable)) {
return true;
}
Iterator> it = this.snapshotHandlers.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = it.next();
SnapshotSentinel sentinel = entry.getValue();
if (snapshot.getName().equals(sentinel.getSnapshot().getName()) && !sentinel.isFinished()) {
return true;
}
}
return false;
}
/**
* Check to see if the specified table has a snapshot in progress. Currently we have a
* limitation only allowing a single snapshot per table at a time.
* @param tableName name of the table being snapshotted.
* @return true if there is a snapshot in progress on the specified table.
*/
synchronized boolean isTakingSnapshot(final TableName tableName) {
SnapshotSentinel handler = this.snapshotHandlers.get(tableName);
return handler != null && !handler.isFinished();
}
/**
* Check to make sure that we are OK to run the passed snapshot. Checks to make sure that we
* aren't already running a snapshot or restore on the requested table.
* @param snapshot description of the snapshot we want to start
* @throws HBaseSnapshotException if the filesystem could not be prepared to start the snapshot
*/
private synchronized void prepareToTakeSnapshot(SnapshotDescription snapshot)
throws HBaseSnapshotException {
FileSystem fs = master.getMasterFileSystem().getFileSystem();
Path workingDir = SnapshotDescriptionUtils.getWorkingSnapshotDir(snapshot, rootDir);
TableName snapshotTable =
TableName.valueOf(snapshot.getTable());
// make sure we aren't already running a snapshot
if (isTakingSnapshot(snapshot)) {
SnapshotSentinel handler = this.snapshotHandlers.get(snapshotTable);
throw new SnapshotCreationException("Rejected taking "
+ ClientSnapshotDescriptionUtils.toString(snapshot)
+ " because we are already running another snapshot "
+ (handler != null ? ("on the same table " +
ClientSnapshotDescriptionUtils.toString(handler.getSnapshot()))
: "with the same name"), snapshot);
}
// make sure we aren't running a restore on the same table
if (isRestoringTable(snapshotTable)) {
SnapshotSentinel handler = restoreHandlers.get(snapshotTable);
throw new SnapshotCreationException("Rejected taking "
+ ClientSnapshotDescriptionUtils.toString(snapshot)
+ " because we are already have a restore in progress on the same snapshot "
+ ClientSnapshotDescriptionUtils.toString(handler.getSnapshot()), snapshot);
}
try {
// delete the working directory, since we aren't running the snapshot. Likely leftovers
// from a failed attempt.
fs.delete(workingDir, true);
// recreate the working directory for the snapshot
if (!fs.mkdirs(workingDir)) {
throw new SnapshotCreationException("Couldn't create working directory (" + workingDir
+ ") for snapshot" , snapshot);
}
} catch (HBaseSnapshotException e) {
throw e;
} catch (IOException e) {
throw new SnapshotCreationException(
"Exception while checking to see if snapshot could be started.", e, snapshot);
}
}
/**
* Take a snapshot of a disabled table.
* @param snapshot description of the snapshot to take. Modified to be {@link Type#DISABLED}.
* @throws HBaseSnapshotException if the snapshot could not be started
*/
private synchronized void snapshotDisabledTable(SnapshotDescription snapshot)
throws HBaseSnapshotException {
// setup the snapshot
prepareToTakeSnapshot(snapshot);
// set the snapshot to be a disabled snapshot, since the client doesn't know about that
snapshot = snapshot.toBuilder().setType(Type.DISABLED).build();
// Take the snapshot of the disabled table
DisabledTableSnapshotHandler handler =
new DisabledTableSnapshotHandler(snapshot, master);
snapshotTable(snapshot, handler);
}
/**
* Take a snapshot of an enabled table.
* @param snapshot description of the snapshot to take.
* @throws HBaseSnapshotException if the snapshot could not be started
*/
private synchronized void snapshotEnabledTable(SnapshotDescription snapshot)
throws HBaseSnapshotException {
// setup the snapshot
prepareToTakeSnapshot(snapshot);
// Take the snapshot of the enabled table
EnabledTableSnapshotHandler handler =
new EnabledTableSnapshotHandler(snapshot, master, this);
snapshotTable(snapshot, handler);
}
/**
* Take a snapshot using the specified handler.
* On failure the snapshot temporary working directory is removed.
* NOTE: prepareToTakeSnapshot() called before this one takes care of the rejecting the
* snapshot request if the table is busy with another snapshot/restore operation.
* @param snapshot the snapshot description
* @param handler the snapshot handler
*/
private synchronized void snapshotTable(SnapshotDescription snapshot,
final TakeSnapshotHandler handler) throws HBaseSnapshotException {
try {
handler.prepare();
this.executorService.submit(handler);
this.snapshotHandlers.put(TableName.valueOf(snapshot.getTable()), handler);
} catch (Exception e) {
// cleanup the working directory by trying to delete it from the fs.
Path workingDir = SnapshotDescriptionUtils.getWorkingSnapshotDir(snapshot, rootDir);
try {
if (!this.master.getMasterFileSystem().getFileSystem().delete(workingDir, true)) {
LOG.error("Couldn't delete working directory (" + workingDir + " for snapshot:" +
ClientSnapshotDescriptionUtils.toString(snapshot));
}
} catch (IOException e1) {
LOG.error("Couldn't delete working directory (" + workingDir + " for snapshot:" +
ClientSnapshotDescriptionUtils.toString(snapshot));
}
// fail the snapshot
throw new SnapshotCreationException("Could not build snapshot handler", e, snapshot);
}
}
/**
* Take a snapshot based on the enabled/disabled state of the table.
*
* @param snapshot
* @throws HBaseSnapshotException when a snapshot specific exception occurs.
* @throws IOException when some sort of generic IO exception occurs.
*/
public void takeSnapshot(SnapshotDescription snapshot) throws IOException {
// check to see if we already completed the snapshot
if (isSnapshotCompleted(snapshot)) {
throw new SnapshotExistsException("Snapshot '" + snapshot.getName()
+ "' already stored on the filesystem.", snapshot);
}
LOG.debug("No existing snapshot, attempting snapshot...");
// stop tracking "abandoned" handlers
cleanupSentinels();
// check to see if the table exists
HTableDescriptor desc = null;
try {
desc = master.getTableDescriptors().get(
TableName.valueOf(snapshot.getTable()));
} catch (FileNotFoundException e) {
String msg = "Table:" + snapshot.getTable() + " info doesn't exist!";
LOG.error(msg);
throw new SnapshotCreationException(msg, e, snapshot);
} catch (IOException e) {
throw new SnapshotCreationException("Error while geting table description for table "
+ snapshot.getTable(), e, snapshot);
}
if (desc == null) {
throw new SnapshotCreationException("Table '" + snapshot.getTable()
+ "' doesn't exist, can't take snapshot.", snapshot);
}
// if not specified, set the snapshot format
if (!snapshot.hasVersion()) {
snapshot = snapshot.toBuilder()
.setVersion(SnapshotDescriptionUtils.SNAPSHOT_LAYOUT_VERSION)
.build();
}
// call pre coproc hook
MasterCoprocessorHost cpHost = master.getMasterCoprocessorHost();
if (cpHost != null) {
cpHost.preSnapshot(snapshot, desc);
}
// if the table is enabled, then have the RS run actually the snapshot work
TableName snapshotTable = TableName.valueOf(snapshot.getTable());
AssignmentManager assignmentMgr = master.getAssignmentManager();
if (assignmentMgr.getTableStateManager().isTableState(snapshotTable,
ZooKeeperProtos.Table.State.ENABLED)) {
LOG.debug("Table enabled, starting distributed snapshot.");
snapshotEnabledTable(snapshot);
LOG.debug("Started snapshot: " + ClientSnapshotDescriptionUtils.toString(snapshot));
}
// For disabled table, snapshot is created by the master
else if (assignmentMgr.getTableStateManager().isTableState(snapshotTable,
ZooKeeperProtos.Table.State.DISABLED)) {
LOG.debug("Table is disabled, running snapshot entirely on master.");
snapshotDisabledTable(snapshot);
LOG.debug("Started snapshot: " + ClientSnapshotDescriptionUtils.toString(snapshot));
} else {
LOG.error("Can't snapshot table '" + snapshot.getTable()
+ "', isn't open or closed, we don't know what to do!");
TablePartiallyOpenException tpoe = new TablePartiallyOpenException(snapshot.getTable()
+ " isn't fully open.");
throw new SnapshotCreationException("Table is not entirely open or closed", tpoe, snapshot);
}
// call post coproc hook
if (cpHost != null) {
cpHost.postSnapshot(snapshot, desc);
}
}
/**
* Set the handler for the current snapshot
*
* Exposed for TESTING
* @param tableName
* @param handler handler the master should use
*
* TODO get rid of this if possible, repackaging, modify tests.
*/
public synchronized void setSnapshotHandlerForTesting(
final TableName tableName,
final SnapshotSentinel handler) {
if (handler != null) {
this.snapshotHandlers.put(tableName, handler);
} else {
this.snapshotHandlers.remove(tableName);
}
}
/**
* @return distributed commit coordinator for all running snapshots
*/
ProcedureCoordinator getCoordinator() {
return coordinator;
}
/**
* Check to see if the snapshot is one of the currently completed snapshots
* Returns true if the snapshot exists in the "completed snapshots folder".
*
* @param snapshot expected snapshot to check
* @return true if the snapshot is stored on the {@link FileSystem}, false if is
* not stored
* @throws IOException if the filesystem throws an unexpected exception,
* @throws IllegalArgumentException if snapshot name is invalid.
*/
private boolean isSnapshotCompleted(SnapshotDescription snapshot) throws IOException {
try {
final Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshot, rootDir);
FileSystem fs = master.getMasterFileSystem().getFileSystem();
// check to see if the snapshot already exists
return fs.exists(snapshotDir);
} catch (IllegalArgumentException iae) {
throw new UnknownSnapshotException("Unexpected exception thrown", iae);
}
}
/**
* Clone the specified snapshot into a new table.
* The operation will fail if the destination table has a snapshot or restore in progress.
*
* @param snapshot Snapshot Descriptor
* @param hTableDescriptor Table Descriptor of the table to create
*/
synchronized void cloneSnapshot(final SnapshotDescription snapshot,
final HTableDescriptor hTableDescriptor) throws HBaseSnapshotException {
TableName tableName = hTableDescriptor.getTableName();
// make sure we aren't running a snapshot on the same table
if (isTakingSnapshot(tableName)) {
throw new RestoreSnapshotException("Snapshot in progress on the restore table=" + tableName);
}
// make sure we aren't running a restore on the same table
if (isRestoringTable(tableName)) {
throw new RestoreSnapshotException("Restore already in progress on the table=" + tableName);
}
try {
CloneSnapshotHandler handler =
new CloneSnapshotHandler(master, snapshot, hTableDescriptor).prepare();
this.executorService.submit(handler);
this.restoreHandlers.put(tableName, handler);
} catch (Exception e) {
String msg = "Couldn't clone the snapshot=" + ClientSnapshotDescriptionUtils.toString(snapshot) +
" on table=" + tableName;
LOG.error(msg, e);
throw new RestoreSnapshotException(msg, e);
}
}
/**
* Restore the specified snapshot
* @param reqSnapshot
* @throws IOException
*/
public void restoreSnapshot(SnapshotDescription reqSnapshot) throws IOException {
FileSystem fs = master.getMasterFileSystem().getFileSystem();
Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(reqSnapshot, rootDir);
MasterCoprocessorHost cpHost = master.getMasterCoprocessorHost();
// check if the snapshot exists
if (!fs.exists(snapshotDir)) {
LOG.error("A Snapshot named '" + reqSnapshot.getName() + "' does not exist.");
throw new SnapshotDoesNotExistException(reqSnapshot);
}
// read snapshot information
SnapshotDescription fsSnapshot = SnapshotDescriptionUtils.readSnapshotInfo(fs, snapshotDir);
SnapshotManifest manifest = SnapshotManifest.open(master.getConfiguration(), fs,
snapshotDir, fsSnapshot);
HTableDescriptor snapshotTableDesc = manifest.getTableDescriptor();
TableName tableName = TableName.valueOf(reqSnapshot.getTable());
// stop tracking "abandoned" handlers
cleanupSentinels();
// Verify snapshot validity
SnapshotReferenceUtil.verifySnapshot(master.getConfiguration(), fs, manifest);
// Execute the restore/clone operation
if (MetaTableAccessor.tableExists(master.getConnection(), tableName)) {
if (master.getAssignmentManager().getTableStateManager().isTableState(
TableName.valueOf(fsSnapshot.getTable()), ZooKeeperProtos.Table.State.ENABLED)) {
throw new UnsupportedOperationException("Table '" +
TableName.valueOf(fsSnapshot.getTable()) + "' must be disabled in order to " +
"perform a restore operation" +
".");
}
// call coproc pre hook
if (cpHost != null) {
cpHost.preRestoreSnapshot(reqSnapshot, snapshotTableDesc);
}
restoreSnapshot(fsSnapshot, snapshotTableDesc);
LOG.info("Restore snapshot=" + fsSnapshot.getName() + " as table=" + tableName);
if (cpHost != null) {
cpHost.postRestoreSnapshot(reqSnapshot, snapshotTableDesc);
}
} else {
HTableDescriptor htd = RestoreSnapshotHelper.cloneTableSchema(snapshotTableDesc, tableName);
if (cpHost != null) {
cpHost.preCloneSnapshot(reqSnapshot, htd);
}
cloneSnapshot(fsSnapshot, htd);
LOG.info("Clone snapshot=" + fsSnapshot.getName() + " as table=" + tableName);
if (cpHost != null) {
cpHost.postCloneSnapshot(reqSnapshot, htd);
}
}
}
/**
* Restore the specified snapshot.
* The restore will fail if the destination table has a snapshot or restore in progress.
*
* @param snapshot Snapshot Descriptor
* @param hTableDescriptor Table Descriptor
*/
private synchronized void restoreSnapshot(final SnapshotDescription snapshot,
final HTableDescriptor hTableDescriptor) throws HBaseSnapshotException {
TableName tableName = hTableDescriptor.getTableName();
// make sure we aren't running a snapshot on the same table
if (isTakingSnapshot(tableName)) {
throw new RestoreSnapshotException("Snapshot in progress on the restore table=" + tableName);
}
// make sure we aren't running a restore on the same table
if (isRestoringTable(tableName)) {
throw new RestoreSnapshotException("Restore already in progress on the table=" + tableName);
}
try {
RestoreSnapshotHandler handler =
new RestoreSnapshotHandler(master, snapshot, hTableDescriptor).prepare();
this.executorService.submit(handler);
restoreHandlers.put(tableName, handler);
} catch (Exception e) {
String msg = "Couldn't restore the snapshot=" + ClientSnapshotDescriptionUtils.toString(
snapshot) +
" on table=" + tableName;
LOG.error(msg, e);
throw new RestoreSnapshotException(msg, e);
}
}
/**
* Verify if the restore of the specified table is in progress.
*
* @param tableName table under restore
* @return true if there is a restore in progress of the specified table.
*/
private synchronized boolean isRestoringTable(final TableName tableName) {
SnapshotSentinel sentinel = this.restoreHandlers.get(tableName);
return(sentinel != null && !sentinel.isFinished());
}
/**
* Returns the status of a restore operation.
* If the in-progress restore is failed throws the exception that caused the failure.
*
* @param snapshot
* @return false if in progress, true if restore is completed or not requested.
* @throws IOException if there was a failure during the restore
*/
public boolean isRestoreDone(final SnapshotDescription snapshot) throws IOException {
// check to see if the sentinel exists,
// and if the task is complete removes it from the in-progress restore map.
SnapshotSentinel sentinel = removeSentinelIfFinished(this.restoreHandlers, snapshot);
// stop tracking "abandoned" handlers
cleanupSentinels();
if (sentinel == null) {
// there is no sentinel so restore is not in progress.
return true;
}
LOG.debug("Verify snapshot=" + snapshot.getName() + " against="
+ sentinel.getSnapshot().getName() + " table=" +
TableName.valueOf(snapshot.getTable()));
// If the restore is failed, rethrow the exception
sentinel.rethrowExceptionIfFailed();
// check to see if we are done
if (sentinel.isFinished()) {
LOG.debug("Restore snapshot=" + ClientSnapshotDescriptionUtils.toString(snapshot) +
" has completed. Notifying the client.");
return true;
}
if (LOG.isDebugEnabled()) {
LOG.debug("Sentinel is not yet finished with restoring snapshot=" +
ClientSnapshotDescriptionUtils.toString(snapshot));
}
return false;
}
/**
* Return the handler if it is currently live and has the same snapshot target name.
* The handler is removed from the sentinels map if completed.
* @param sentinels live handlers
* @param snapshot snapshot description
* @return null if doesn't match, else a live handler.
*/
private synchronized SnapshotSentinel removeSentinelIfFinished(
final Map sentinels,
final SnapshotDescription snapshot) {
if (!snapshot.hasTable()) {
return null;
}
TableName snapshotTable = TableName.valueOf(snapshot.getTable());
SnapshotSentinel h = sentinels.get(snapshotTable);
if (h == null) {
return null;
}
if (!h.getSnapshot().getName().equals(snapshot.getName())) {
// specified snapshot is to the one currently running
return null;
}
// Remove from the "in-progress" list once completed
if (h.isFinished()) {
sentinels.remove(snapshotTable);
}
return h;
}
/**
* Removes "abandoned" snapshot/restore requests.
* As part of the HBaseAdmin snapshot/restore API the operation status is checked until completed,
* and the in-progress maps are cleaned up when the status of a completed task is requested.
* To avoid having sentinels staying around for long time if something client side is failed,
* each operation tries to clean up the in-progress maps sentinels finished from a long time.
*/
private void cleanupSentinels() {
cleanupSentinels(this.snapshotHandlers);
cleanupSentinels(this.restoreHandlers);
}
/**
* Remove the sentinels that are marked as finished and the completion time
* has exceeded the removal timeout.
* @param sentinels map of sentinels to clean
*/
private synchronized void cleanupSentinels(final Map sentinels) {
long currentTime = EnvironmentEdgeManager.currentTime();
Iterator> it =
sentinels.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = it.next();
SnapshotSentinel sentinel = entry.getValue();
if (sentinel.isFinished() &&
(currentTime - sentinel.getCompletionTimestamp()) > SNAPSHOT_SENTINELS_CLEANUP_TIMEOUT)
{
it.remove();
}
}
}
//
// Implementing Stoppable interface
//
@Override
public void stop(String why) {
// short circuit
if (this.stopped) return;
// make sure we get stop
this.stopped = true;
// pass the stop onto take snapshot handlers
for (SnapshotSentinel snapshotHandler: this.snapshotHandlers.values()) {
snapshotHandler.cancel(why);
}
// pass the stop onto all the restore handlers
for (SnapshotSentinel restoreHandler: this.restoreHandlers.values()) {
restoreHandler.cancel(why);
}
try {
coordinator.close();
} catch (IOException e) {
LOG.error("stop ProcedureCoordinator error", e);
}
}
@Override
public boolean isStopped() {
return this.stopped;
}
/**
* Throws an exception if snapshot operations (take a snapshot, restore, clone) are not supported.
* Called at the beginning of snapshot() and restoreSnapshot() methods.
* @throws UnsupportedOperationException if snapshot are not supported
*/
public void checkSnapshotSupport() throws UnsupportedOperationException {
if (!this.isSnapshotSupported) {
throw new UnsupportedOperationException(
"To use snapshots, You must add to the hbase-site.xml of the HBase Master: '" +
HBASE_SNAPSHOT_ENABLED + "' property with value 'true'.");
}
}
/**
* Called at startup, to verify if snapshot operation is supported, and to avoid
* starting the master if there're snapshots present but the cleaners needed are missing.
* Otherwise we can end up with snapshot data loss.
* @param conf The {@link Configuration} object to use
* @param mfs The MasterFileSystem to use
* @throws IOException in case of file-system operation failure
* @throws UnsupportedOperationException in case cleaners are missing and
* there're snapshot in the system
*/
private void checkSnapshotSupport(final Configuration conf, final MasterFileSystem mfs)
throws IOException, UnsupportedOperationException {
// Verify if snapshot is disabled by the user
String enabled = conf.get(HBASE_SNAPSHOT_ENABLED);
boolean snapshotEnabled = conf.getBoolean(HBASE_SNAPSHOT_ENABLED, false);
boolean userDisabled = (enabled != null && enabled.trim().length() > 0 && !snapshotEnabled);
// Extract cleaners from conf
Set hfileCleaners = new HashSet();
String[] cleaners = conf.getStrings(HFileCleaner.MASTER_HFILE_CLEANER_PLUGINS);
if (cleaners != null) Collections.addAll(hfileCleaners, cleaners);
Set logCleaners = new HashSet();
cleaners = conf.getStrings(HConstants.HBASE_MASTER_LOGCLEANER_PLUGINS);
if (cleaners != null) Collections.addAll(logCleaners, cleaners);
// check if an older version of snapshot directory was present
Path oldSnapshotDir = new Path(mfs.getRootDir(), HConstants.OLD_SNAPSHOT_DIR_NAME);
FileSystem fs = mfs.getFileSystem();
List ss = getCompletedSnapshots(new Path(rootDir, oldSnapshotDir));
if (ss != null && !ss.isEmpty()) {
LOG.error("Snapshots from an earlier release were found under: " + oldSnapshotDir);
LOG.error("Please rename the directory as " + HConstants.SNAPSHOT_DIR_NAME);
}
// If the user has enabled the snapshot, we force the cleaners to be present
// otherwise we still need to check if cleaners are enabled or not and verify
// that there're no snapshot in the .snapshot folder.
if (snapshotEnabled) {
// Inject snapshot cleaners, if snapshot.enable is true
hfileCleaners.add(SnapshotHFileCleaner.class.getName());
hfileCleaners.add(HFileLinkCleaner.class.getName());
logCleaners.add(SnapshotLogCleaner.class.getName());
// Set cleaners conf
conf.setStrings(HFileCleaner.MASTER_HFILE_CLEANER_PLUGINS,
hfileCleaners.toArray(new String[hfileCleaners.size()]));
conf.setStrings(HConstants.HBASE_MASTER_LOGCLEANER_PLUGINS,
logCleaners.toArray(new String[logCleaners.size()]));
} else {
// Verify if cleaners are present
snapshotEnabled = logCleaners.contains(SnapshotLogCleaner.class.getName()) &&
hfileCleaners.contains(SnapshotHFileCleaner.class.getName()) &&
hfileCleaners.contains(HFileLinkCleaner.class.getName());
// Warn if the cleaners are enabled but the snapshot.enabled property is false/not set.
if (snapshotEnabled) {
LOG.warn("Snapshot log and hfile cleaners are present in the configuration, " +
"but the '" + HBASE_SNAPSHOT_ENABLED + "' property " +
(userDisabled ? "is set to 'false'." : "is not set."));
}
}
// Mark snapshot feature as enabled if cleaners are present and user has not disabled it.
this.isSnapshotSupported = snapshotEnabled && !userDisabled;
// If cleaners are not enabled, verify that there're no snapshot in the .snapshot folder
// otherwise we end up with snapshot data loss.
if (!snapshotEnabled) {
LOG.info("Snapshot feature is not enabled, missing log and hfile cleaners.");
Path snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(mfs.getRootDir());
if (fs.exists(snapshotDir)) {
FileStatus[] snapshots = FSUtils.listStatus(fs, snapshotDir,
new SnapshotDescriptionUtils.CompletedSnaphotDirectoriesFilter(fs));
if (snapshots != null) {
LOG.error("Snapshots are present, but cleaners are not enabled.");
checkSnapshotSupport();
}
}
}
}
@Override
public void initialize(MasterServices master, MetricsMaster metricsMaster) throws KeeperException,
IOException, UnsupportedOperationException {
this.master = master;
this.rootDir = master.getMasterFileSystem().getRootDir();
checkSnapshotSupport(master.getConfiguration(), master.getMasterFileSystem());
// get the configuration for the coordinator
Configuration conf = master.getConfiguration();
long wakeFrequency = conf.getInt(SNAPSHOT_WAKE_MILLIS_KEY, SNAPSHOT_WAKE_MILLIS_DEFAULT);
long timeoutMillis = conf.getLong(SNAPSHOT_TIMEOUT_MILLIS_KEY, SNAPSHOT_TIMEOUT_MILLIS_DEFAULT);
int opThreads = conf.getInt(SNAPSHOT_POOL_THREADS_KEY, SNAPSHOT_POOL_THREADS_DEFAULT);
// setup the default procedure coordinator
String name = master.getServerName().toString();
ThreadPoolExecutor tpool = ProcedureCoordinator.defaultPool(name, opThreads);
ProcedureCoordinatorRpcs comms = new ZKProcedureCoordinatorRpcs(
master.getZooKeeper(), SnapshotManager.ONLINE_SNAPSHOT_CONTROLLER_DESCRIPTION, name);
this.coordinator = new ProcedureCoordinator(comms, tpool, timeoutMillis, wakeFrequency);
this.executorService = master.getExecutorService();
resetTempDir();
}
@Override
public String getProcedureSignature() {
return ONLINE_SNAPSHOT_CONTROLLER_DESCRIPTION;
}
@Override
public void execProcedure(ProcedureDescription desc) throws IOException {
takeSnapshot(toSnapshotDescription(desc));
}
@Override
public boolean isProcedureDone(ProcedureDescription desc) throws IOException {
return isSnapshotDone(toSnapshotDescription(desc));
}
private SnapshotDescription toSnapshotDescription(ProcedureDescription desc)
throws IOException {
SnapshotDescription.Builder builder = SnapshotDescription.newBuilder();
if (!desc.hasInstance()) {
throw new IOException("Snapshot name is not defined: " + desc.toString());
}
String snapshotName = desc.getInstance();
List props = desc.getConfigurationList();
String table = null;
for (NameStringPair prop : props) {
if ("table".equalsIgnoreCase(prop.getName())) {
table = prop.getValue();
}
}
if (table == null) {
throw new IOException("Snapshot table is not defined: " + desc.toString());
}
TableName tableName = TableName.valueOf(table);
builder.setTable(tableName.getNameAsString());
builder.setName(snapshotName);
builder.setType(SnapshotDescription.Type.FLUSH);
return builder.build();
}
}