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1   /*
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.replication;
20  
21  import java.io.IOException;
22  import java.util.ArrayList;
23  import java.util.List;
24  import java.util.Map;
25  import java.util.Set;
26  import java.util.TreeMap;
27  import java.util.concurrent.ConcurrentHashMap;
28  import java.util.concurrent.ConcurrentMap;
29  
30  import org.apache.commons.logging.Log;
31  import org.apache.commons.logging.LogFactory;
32  import org.apache.hadoop.conf.Configuration;
33  import org.apache.hadoop.hbase.Abortable;
34  import org.apache.hadoop.hbase.CompoundConfiguration;
35  import org.apache.hadoop.hbase.classification.InterfaceAudience;
36  import org.apache.hadoop.hbase.exceptions.DeserializationException;
37  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
38  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.BytesBytesPair;
39  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.NameStringPair;
40  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
41  import org.apache.hadoop.hbase.replication.ReplicationPeer.PeerState;
42  import org.apache.hadoop.hbase.util.Bytes;
43  import org.apache.hadoop.hbase.util.Pair;
44  import org.apache.hadoop.hbase.zookeeper.ZKUtil;
45  import org.apache.hadoop.hbase.zookeeper.ZKUtil.ZKUtilOp;
46  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
47  import org.apache.zookeeper.KeeperException;
48  
49  import com.google.protobuf.ByteString;
50  import com.google.protobuf.InvalidProtocolBufferException;
51  
52  /**
53   * This class provides an implementation of the ReplicationPeers interface using Zookeeper. The
54   * peers znode contains a list of all peer replication clusters and the current replication state of
55   * those clusters. It has one child peer znode for each peer cluster. The peer znode is named with
56   * the cluster id provided by the user in the HBase shell. The value of the peer znode contains the
57   * peers cluster key provided by the user in the HBase Shell. The cluster key contains a list of
58   * zookeeper quorum peers, the client port for the zookeeper quorum, and the base znode for HBase.
59   * For example:
60   *
61   *  /hbase/replication/peers/1 [Value: zk1.host.com,zk2.host.com,zk3.host.com:2181:/hbase]
62   *  /hbase/replication/peers/2 [Value: zk5.host.com,zk6.host.com,zk7.host.com:2181:/hbase]
63   *
64   * Each of these peer znodes has a child znode that indicates whether or not replication is enabled
65   * on that peer cluster. These peer-state znodes do not have child znodes and simply contain a
66   * boolean value (i.e. ENABLED or DISABLED). This value is read/maintained by the
67   * ReplicationPeer.PeerStateTracker class. For example:
68   *
69   * /hbase/replication/peers/1/peer-state [Value: ENABLED]
70   *
71   * Each of these peer znodes has a child znode that indicates which data will be replicated
72   * to the peer cluster. These peer-tableCFs znodes do not have child znodes and only have a
73   * table/cf list config. This value is read/maintained by the ReplicationPeer.TableCFsTracker
74   * class. For example:
75   *
76   * /hbase/replication/peers/1/tableCFs [Value: "table1; table2:cf1,cf3; table3:cfx,cfy"]
77   */
78  @InterfaceAudience.Private
79  public class ReplicationPeersZKImpl extends ReplicationStateZKBase implements ReplicationPeers {
80  
81    // Map of peer clusters keyed by their id
82    private Map<String, ReplicationPeerZKImpl> peerClusters;
83    private final String tableCFsNodeName;
84  
85    private static final Log LOG = LogFactory.getLog(ReplicationPeersZKImpl.class);
86  
87    public ReplicationPeersZKImpl(final ZooKeeperWatcher zk, final Configuration conf,
88        Abortable abortable) {
89      super(zk, conf, abortable);
90      this.tableCFsNodeName = conf.get("zookeeper.znode.replication.peers.tableCFs", "tableCFs");
91      this.peerClusters = new ConcurrentHashMap<String, ReplicationPeerZKImpl>();
92    }
93  
94    @Override
95    public void init() throws ReplicationException {
96      try {
97        if (ZKUtil.checkExists(this.zookeeper, this.peersZNode) < 0) {
98          ZKUtil.createWithParents(this.zookeeper, this.peersZNode);
99        }
100     } catch (KeeperException e) {
101       throw new ReplicationException("Could not initialize replication peers", e);
102     }
103     addExistingPeers();
104   }
105 
106   @Override
107   public void addPeer(String id, ReplicationPeerConfig peerConfig, String tableCFs)
108       throws ReplicationException {
109     try {
110       if (peerExists(id)) {
111         throw new IllegalArgumentException("Cannot add a peer with id=" + id
112             + " because that id already exists.");
113       }
114       
115       if(id.contains("-")){
116         throw new IllegalArgumentException("Found invalid peer name:" + id);
117       }
118       
119       ZKUtil.createWithParents(this.zookeeper, this.peersZNode);
120       List<ZKUtilOp> listOfOps = new ArrayList<ZKUtil.ZKUtilOp>();
121       ZKUtilOp op1 =
122           ZKUtilOp.createAndFailSilent(ZKUtil.joinZNode(this.peersZNode, id),
123             toByteArray(peerConfig));
124       // There is a race (if hbase.zookeeper.useMulti is false)
125       // b/w PeerWatcher and ReplicationZookeeper#add method to create the
126       // peer-state znode. This happens while adding a peer
127       // The peer state data is set as "ENABLED" by default.
128       ZKUtilOp op2 = ZKUtilOp.createAndFailSilent(getPeerStateNode(id), ENABLED_ZNODE_BYTES);
129       String tableCFsStr = (tableCFs == null) ? "" : tableCFs;
130       ZKUtilOp op3 = ZKUtilOp.createAndFailSilent(getTableCFsNode(id), Bytes.toBytes(tableCFsStr));
131       listOfOps.add(op1);
132       listOfOps.add(op2);
133       listOfOps.add(op3);
134       ZKUtil.multiOrSequential(this.zookeeper, listOfOps, false);
135     } catch (KeeperException e) {
136       throw new ReplicationException("Could not add peer with id=" + id + ", peerConfif="
137           + peerConfig, e);
138     }
139   }
140 
141   @Override
142   public void removePeer(String id) throws ReplicationException {
143     try {
144       if (!peerExists(id)) {
145         throw new IllegalArgumentException("Cannot remove peer with id=" + id
146             + " because that id does not exist.");
147       }
148       ZKUtil.deleteNodeRecursively(this.zookeeper, ZKUtil.joinZNode(this.peersZNode, id));
149     } catch (KeeperException e) {
150       throw new ReplicationException("Could not remove peer with id=" + id, e);
151     }
152   }
153 
154   @Override
155   public void enablePeer(String id) throws ReplicationException {
156     changePeerState(id, ZooKeeperProtos.ReplicationState.State.ENABLED);
157     LOG.info("peer " + id + " is enabled");
158   }
159 
160   @Override
161   public void disablePeer(String id) throws ReplicationException {
162     changePeerState(id, ZooKeeperProtos.ReplicationState.State.DISABLED);
163     LOG.info("peer " + id + " is disabled");
164   }
165 
166   @Override
167   public String getPeerTableCFsConfig(String id) throws ReplicationException {
168     try {
169       if (!peerExists(id)) {
170         throw new IllegalArgumentException("peer " + id + " doesn't exist");
171       }
172       try {
173         return Bytes.toString(ZKUtil.getData(this.zookeeper, getTableCFsNode(id)));
174       } catch (Exception e) {
175         throw new ReplicationException(e);
176       }
177     } catch (KeeperException e) {
178       throw new ReplicationException("Unable to get tableCFs of the peer with id=" + id, e);
179     }
180   }
181 
182   @Override
183   public void setPeerTableCFsConfig(String id, String tableCFsStr) throws ReplicationException {
184     try {
185       if (!peerExists(id)) {
186         throw new IllegalArgumentException("Cannot set peer tableCFs because id=" + id
187             + " does not exist.");
188       }
189       String tableCFsZKNode = getTableCFsNode(id);
190       byte[] tableCFs = Bytes.toBytes(tableCFsStr);
191       if (ZKUtil.checkExists(this.zookeeper, tableCFsZKNode) != -1) {
192         ZKUtil.setData(this.zookeeper, tableCFsZKNode, tableCFs);
193       } else {
194         ZKUtil.createAndWatch(this.zookeeper, tableCFsZKNode, tableCFs);
195       }
196       LOG.info("Peer tableCFs with id= " + id + " is now " + tableCFsStr);
197     } catch (KeeperException e) {
198       throw new ReplicationException("Unable to change tableCFs of the peer with id=" + id, e);
199     }
200   }
201 
202   @Override
203   public Map<String, List<String>> getTableCFs(String id) throws IllegalArgumentException {
204     ReplicationPeer replicationPeer = this.peerClusters.get(id);
205     if (replicationPeer == null) {
206       throw new IllegalArgumentException("Peer with id= " + id + " is not connected");
207     }
208     return replicationPeer.getTableCFs();
209   }
210 
211   @Override
212   public boolean getStatusOfPeer(String id) {
213     ReplicationPeer replicationPeer = this.peerClusters.get(id);
214     if (replicationPeer == null) {
215       throw new IllegalArgumentException("Peer with id= " + id + " is not connected");
216     } 
217     return this.peerClusters.get(id).getPeerState() == PeerState.ENABLED;
218   }
219 
220   @Override
221   public boolean getStatusOfPeerFromBackingStore(String id) throws ReplicationException {
222     try {
223       if (!peerExists(id)) {
224         throw new IllegalArgumentException("peer " + id + " doesn't exist");
225       }
226       String peerStateZNode = getPeerStateNode(id);
227       try {
228         return ReplicationPeerZKImpl.isStateEnabled(ZKUtil.getData(this.zookeeper, peerStateZNode));
229       } catch (KeeperException e) {
230         throw new ReplicationException(e);
231       } catch (DeserializationException e) {
232         throw new ReplicationException(e);
233       }
234     } catch (KeeperException e) {
235       throw new ReplicationException("Unable to get status of the peer with id=" + id +
236           " from backing store", e);
237     }
238   }
239 
240   @Override
241   public Map<String, ReplicationPeerConfig> getAllPeerConfigs() {
242     Map<String, ReplicationPeerConfig> peers = new TreeMap<String, ReplicationPeerConfig>();
243     List<String> ids = null;
244     try {
245       ids = ZKUtil.listChildrenNoWatch(this.zookeeper, this.peersZNode);
246       for (String id : ids) {
247         ReplicationPeerConfig peerConfig = getReplicationPeerConfig(id);
248         if (peerConfig == null) {
249           LOG.warn("Failed to get replication peer configuration of clusterid=" + id
250               + " znode content, continuing.");
251           continue;
252         }
253         peers.put(id, peerConfig);
254       }
255     } catch (KeeperException e) {
256       this.abortable.abort("Cannot get the list of peers ", e);
257     } catch (ReplicationException e) {
258       this.abortable.abort("Cannot get the list of peers ", e);
259     }
260     return peers;
261   }
262 
263   @Override
264   public ReplicationPeerConfig getReplicationPeerConfig(String peerId) throws ReplicationException {
265     String znode = ZKUtil.joinZNode(this.peersZNode, peerId);
266     byte[] data = null;
267     try {
268       data = ZKUtil.getData(this.zookeeper, znode);
269     } catch (KeeperException e) {
270       throw new ReplicationException("Error getting configuration for peer with id=" + peerId, e);
271     }
272     if (data == null) {
273       LOG.error("Could not get configuration for peer because it doesn't exist. peerId=" + peerId);
274       return null;
275     }
276 
277     try {
278       return parsePeerFrom(data);
279     } catch (DeserializationException e) {
280       LOG.warn("Failed to parse cluster key from peerId=" + peerId
281           + ", specifically the content from the following znode: " + znode);
282       return null;
283     }
284   }
285   
286   @Override
287   public Pair<ReplicationPeerConfig, Configuration> getPeerConf(String peerId)
288       throws ReplicationException {
289     ReplicationPeerConfig peerConfig = getReplicationPeerConfig(peerId);
290 
291     if (peerConfig == null) {
292       return null;
293     }
294 
295     Configuration otherConf = new Configuration(this.conf);
296     try {
297       if (peerConfig.getClusterKey() != null && !peerConfig.getClusterKey().isEmpty()) {
298         ZKUtil.applyClusterKeyToConf(otherConf, peerConfig.getClusterKey());
299       }
300     } catch (IOException e) {
301       LOG.error("Can't get peer configuration for peerId=" + peerId + " because:", e);
302       return null;
303     }
304 
305     if (!peerConfig.getConfiguration().isEmpty()) {
306       CompoundConfiguration compound = new CompoundConfiguration();
307       compound.add(otherConf);
308       compound.addStringMap(peerConfig.getConfiguration());
309       return new Pair<ReplicationPeerConfig, Configuration>(peerConfig, compound);
310     }
311 
312     return new Pair<ReplicationPeerConfig, Configuration>(peerConfig, otherConf);
313   }
314   
315   @Override
316   public Set<String> getPeerIds() {
317     return peerClusters.keySet(); // this is not thread-safe
318   }
319 
320   @Override
321   public ReplicationPeer getPeer(String peerId) {
322     return peerClusters.get(peerId);
323   }
324   
325   /**
326    * List all registered peer clusters and set a watch on their znodes.
327    */
328   @Override
329   public List<String> getAllPeerIds() {
330     List<String> ids = null;
331     try {
332       ids = ZKUtil.listChildrenAndWatchThem(this.zookeeper, this.peersZNode);
333     } catch (KeeperException e) {
334       this.abortable.abort("Cannot get the list of peers ", e);
335     }
336     return ids;
337   }
338 
339   /**
340    * A private method used during initialization. This method attempts to add all registered
341    * peer clusters. This method does not set a watch on the peer cluster znodes.
342    */
343   private void addExistingPeers() throws ReplicationException {
344     List<String> znodes = null;
345     try {
346       znodes = ZKUtil.listChildrenNoWatch(this.zookeeper, this.peersZNode);
347     } catch (KeeperException e) {
348       throw new ReplicationException("Error getting the list of peer clusters.", e);
349     }
350     if (znodes != null) {
351       for (String z : znodes) {
352         createAndAddPeer(z);
353       }
354     }
355   }
356 
357   @Override
358   public boolean peerAdded(String peerId) throws ReplicationException {
359     return createAndAddPeer(peerId);
360   }
361 
362   @Override
363   public void peerRemoved(String peerId) {
364     ReplicationPeer rp = this.peerClusters.get(peerId);
365     if (rp != null) {
366       this.peerClusters.remove(peerId);
367     }
368   }
369 
370   /**
371    * Attempt to connect to a new remote slave cluster.
372    * @param peerId a short that identifies the cluster
373    * @return true if a new connection was made, false if no new connection was made.
374    */
375   public boolean createAndAddPeer(String peerId) throws ReplicationException {
376     if (peerClusters == null) {
377       return false;
378     }
379     if (this.peerClusters.containsKey(peerId)) {
380       return false;
381     }
382 
383     ReplicationPeerZKImpl peer = null;
384     try {
385       peer = createPeer(peerId);
386     } catch (Exception e) {
387       throw new ReplicationException("Error adding peer with id=" + peerId, e);
388     }
389     if (peer == null) {
390       return false;
391     }
392     ReplicationPeerZKImpl previous = ((ConcurrentMap<String, ReplicationPeerZKImpl>) peerClusters)
393         .putIfAbsent(peerId, peer);
394     if (previous == null) {
395       LOG.info("Added new peer cluster=" + peer.getPeerConfig().getClusterKey());
396     } else {
397       LOG.info("Peer already present, " + previous.getPeerConfig().getClusterKey()
398           + ", new cluster=" + peer.getPeerConfig().getClusterKey());
399     }
400     return true;
401   }
402 
403   private String getTableCFsNode(String id) {
404     return ZKUtil.joinZNode(this.peersZNode, ZKUtil.joinZNode(id, this.tableCFsNodeName));
405   }
406 
407   private String getPeerStateNode(String id) {
408     return ZKUtil.joinZNode(this.peersZNode, ZKUtil.joinZNode(id, this.peerStateNodeName));
409   }
410 
411   /**
412    * Update the state znode of a peer cluster.
413    * @param id
414    * @param state
415    */
416   private void changePeerState(String id, ZooKeeperProtos.ReplicationState.State state)
417       throws ReplicationException {
418     try {
419       if (!peerExists(id)) {
420         throw new IllegalArgumentException("Cannot enable/disable peer because id=" + id
421             + " does not exist.");
422       }
423       String peerStateZNode = getPeerStateNode(id);
424       byte[] stateBytes =
425           (state == ZooKeeperProtos.ReplicationState.State.ENABLED) ? ENABLED_ZNODE_BYTES
426               : DISABLED_ZNODE_BYTES;
427       if (ZKUtil.checkExists(this.zookeeper, peerStateZNode) != -1) {
428         ZKUtil.setData(this.zookeeper, peerStateZNode, stateBytes);
429       } else {
430         ZKUtil.createAndWatch(this.zookeeper, peerStateZNode, stateBytes);
431       }
432       LOG.info("Peer with id= " + id + " is now " + state.name());
433     } catch (KeeperException e) {
434       throw new ReplicationException("Unable to change state of the peer with id=" + id, e);
435     }
436   }
437 
438   /**
439    * Helper method to connect to a peer
440    * @param peerId peer's identifier
441    * @return object representing the peer
442    * @throws ReplicationException
443    */
444   private ReplicationPeerZKImpl createPeer(String peerId) throws ReplicationException {
445     Pair<ReplicationPeerConfig, Configuration> pair = getPeerConf(peerId);
446     if (pair == null) {
447       return null;
448     }
449     Configuration peerConf = pair.getSecond();
450 
451     ReplicationPeerZKImpl peer = new ReplicationPeerZKImpl(peerConf, peerId, pair.getFirst());
452     try {
453       peer.startStateTracker(this.zookeeper, this.getPeerStateNode(peerId));
454     } catch (KeeperException e) {
455       throw new ReplicationException("Error starting the peer state tracker for peerId=" +
456           peerId, e);
457     }
458 
459     try {
460       peer.startTableCFsTracker(this.zookeeper, this.getTableCFsNode(peerId));
461     } catch (KeeperException e) {
462       throw new ReplicationException("Error starting the peer tableCFs tracker for peerId=" +
463           peerId, e);
464     }
465 
466     return peer;
467   }
468 
469   /**
470    * @param bytes Content of a peer znode.
471    * @return ClusterKey parsed from the passed bytes.
472    * @throws DeserializationException
473    */
474   private static ReplicationPeerConfig parsePeerFrom(final byte[] bytes)
475       throws DeserializationException {
476     if (ProtobufUtil.isPBMagicPrefix(bytes)) {
477       int pblen = ProtobufUtil.lengthOfPBMagic();
478       ZooKeeperProtos.ReplicationPeer.Builder builder =
479           ZooKeeperProtos.ReplicationPeer.newBuilder();
480       ZooKeeperProtos.ReplicationPeer peer;
481       try {
482         peer = builder.mergeFrom(bytes, pblen, bytes.length - pblen).build();
483       } catch (InvalidProtocolBufferException e) {
484         throw new DeserializationException(e);
485       }
486       return convert(peer);
487     } else {
488       if (bytes.length > 0) {
489         return new ReplicationPeerConfig().setClusterKey(Bytes.toString(bytes));
490       }
491       return new ReplicationPeerConfig().setClusterKey("");
492     }
493   }
494 
495   private static ReplicationPeerConfig convert(ZooKeeperProtos.ReplicationPeer peer) {
496     ReplicationPeerConfig peerConfig = new ReplicationPeerConfig();
497     if (peer.hasClusterkey()) {
498       peerConfig.setClusterKey(peer.getClusterkey());
499     }
500     if (peer.hasReplicationEndpointImpl()) {
501       peerConfig.setReplicationEndpointImpl(peer.getReplicationEndpointImpl());
502     }
503 
504     for (BytesBytesPair pair : peer.getDataList()) {
505       peerConfig.getPeerData().put(pair.getFirst().toByteArray(), pair.getSecond().toByteArray());
506     }
507 
508     for (NameStringPair pair : peer.getConfigurationList()) {
509       peerConfig.getConfiguration().put(pair.getName(), pair.getValue());
510     }
511     return peerConfig;
512   }
513 
514   private static ZooKeeperProtos.ReplicationPeer convert(ReplicationPeerConfig  peerConfig) {
515     ZooKeeperProtos.ReplicationPeer.Builder builder = ZooKeeperProtos.ReplicationPeer.newBuilder();
516     if (peerConfig.getClusterKey() != null) {
517       builder.setClusterkey(peerConfig.getClusterKey());
518     }
519     if (peerConfig.getReplicationEndpointImpl() != null) {
520       builder.setReplicationEndpointImpl(peerConfig.getReplicationEndpointImpl());
521     }
522 
523     for (Map.Entry<byte[], byte[]> entry : peerConfig.getPeerData().entrySet()) {
524       builder.addData(BytesBytesPair.newBuilder()
525         .setFirst(ByteString.copyFrom(entry.getKey()))
526         .setSecond(ByteString.copyFrom(entry.getValue()))
527           .build());
528     }
529 
530     for (Map.Entry<String, String> entry : peerConfig.getConfiguration().entrySet()) {
531       builder.addConfiguration(NameStringPair.newBuilder()
532         .setName(entry.getKey())
533         .setValue(entry.getValue())
534         .build());
535     }
536 
537     return builder.build();
538   }
539 
540   /**
541    * @param peerConfig
542    * @return Serialized protobuf of <code>peerConfig</code> with pb magic prefix prepended suitable
543    *         for use as content of a this.peersZNode; i.e. the content of PEER_ID znode under
544    *         /hbase/replication/peers/PEER_ID
545    */
546   private static byte[] toByteArray(final ReplicationPeerConfig peerConfig) {
547     byte[] bytes = convert(peerConfig).toByteArray();
548     return ProtobufUtil.prependPBMagic(bytes);
549   }
550 
551 
552 }