/**
* 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.util;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.client.RegionReplicaUtil;
import org.apache.hadoop.hbase.client.replication.ReplicationAdmin;
import org.apache.hadoop.hbase.io.HFileLink;
import org.apache.hadoop.hbase.io.Reference;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
import org.apache.hadoop.hbase.replication.ReplicationException;
import org.apache.hadoop.hbase.replication.ReplicationPeerConfig;
import org.apache.hadoop.hbase.replication.regionserver.RegionReplicaReplicationEndpoint;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
/**
* Similar to {@link RegionReplicaUtil} but for the server side
*/
public class ServerRegionReplicaUtil extends RegionReplicaUtil {
/**
* Whether asynchronous WAL replication to the secondary region replicas is enabled or not.
* If this is enabled, a replication peer named "region_replica_replication" will be created
* which will tail the logs and replicate the mutatations to region replicas for tables that
* have region replication > 1. If this is enabled once, disabling this replication also
* requires disabling the replication peer using shell or ReplicationAdmin java class.
* Replication to secondary region replicas works over standard inter-cluster replication.·
* So replication, if disabled explicitly, also has to be enabled by setting "hbase.replication"·
* to true for this feature to work.
*/
public static final String REGION_REPLICA_REPLICATION_CONF_KEY
= "hbase.region.replica.replication.enabled";
private static final boolean DEFAULT_REGION_REPLICA_REPLICATION = false;
private static final String REGION_REPLICA_REPLICATION_PEER = "region_replica_replication";
/**
* Returns the regionInfo object to use for interacting with the file system.
* @return An HRegionInfo object to interact with the filesystem
*/
public static HRegionInfo getRegionInfoForFs(HRegionInfo regionInfo) {
if (regionInfo == null) {
return null;
}
return RegionReplicaUtil.getRegionInfoForDefaultReplica(regionInfo);
}
/**
* Returns whether this region replica can accept writes.
* @param region the HRegion object
* @return whether the replica is read only
*/
public static boolean isReadOnly(HRegion region) {
return region.getTableDesc().isReadOnly()
|| !isDefaultReplica(region.getRegionInfo());
}
/**
* Returns whether to replay the recovered edits to flush the results.
* Currently secondary region replicas do not replay the edits, since it would
* cause flushes which might affect the primary region. Primary regions even opened
* in read only mode should replay the edits.
* @param region the HRegion object
* @return whether recovered edits should be replayed.
*/
public static boolean shouldReplayRecoveredEdits(HRegion region) {
return isDefaultReplica(region.getRegionInfo());
}
/**
* Returns a StoreFileInfo from the given FileStatus. Secondary replicas refer to the
* files of the primary region, so an HFileLink is used to construct the StoreFileInfo. This
* way ensures that the secondary will be able to continue reading the store files even if
* they are moved to archive after compaction
* @throws IOException
*/
public static StoreFileInfo getStoreFileInfo(Configuration conf, FileSystem fs,
HRegionInfo regionInfo, HRegionInfo regionInfoForFs, String familyName, FileStatus status)
throws IOException {
// if this is a primary region, just return the StoreFileInfo constructed from path
if (regionInfo.equals(regionInfoForFs)) {
return new StoreFileInfo(conf, fs, status);
}
if (StoreFileInfo.isReference(status.getPath())) {
Reference reference = Reference.read(fs, status.getPath());
return new StoreFileInfo(conf, fs, status, reference);
}
// else create a store file link. The link file does not exists on filesystem though.
HFileLink link = new HFileLink(conf,
HFileLink.createPath(regionInfoForFs.getTable(), regionInfoForFs.getEncodedName()
, familyName, status.getPath().getName()));
return new StoreFileInfo(conf, fs, status, link);
}
/**
* Create replication peer for replicating to region replicas if needed.
* @param conf configuration to use
* @throws IOException
*/
public static void setupRegionReplicaReplication(Configuration conf) throws IOException {
if (!conf.getBoolean(REGION_REPLICA_REPLICATION_CONF_KEY, DEFAULT_REGION_REPLICA_REPLICATION)) {
return;
}
ReplicationAdmin repAdmin = new ReplicationAdmin(conf);
try {
if (repAdmin.getPeerConfig(REGION_REPLICA_REPLICATION_PEER) == null) {
ReplicationPeerConfig peerConfig = new ReplicationPeerConfig();
peerConfig.setClusterKey(ZKUtil.getZooKeeperClusterKey(conf));
peerConfig.setReplicationEndpointImpl(RegionReplicaReplicationEndpoint.class.getName());
repAdmin.addPeer(REGION_REPLICA_REPLICATION_PEER, peerConfig, null);
}
} catch (ReplicationException ex) {
throw new IOException(ex);
} finally {
repAdmin.close();
}
}
/**
* Return the peer id used for replicating to secondary region replicas
*/
public static String getReplicationPeerId() {
return REGION_REPLICA_REPLICATION_PEER;
}
}