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.List;
23 import java.util.Map;
24 import java.util.Set;
25 import java.util.UUID;
26
27 import org.apache.hadoop.classification.InterfaceAudience;
28 import org.apache.hadoop.conf.Configuration;
29 import org.apache.hadoop.hbase.ServerName;
30 import org.apache.zookeeper.KeeperException;
31
32 /**
33 * This provides an interface for maintaining a set of peer clusters. These peers are remote slave
34 * clusters that data is replicated to. A peer cluster can be in three different states:
35 *
36 * 1. Not-Registered - There is no notion of the peer cluster.
37 * 2. Registered - The peer has an id and is being tracked but there is no connection.
38 * 3. Connected - There is an active connection to the remote peer.
39 *
40 * In the registered or connected state, a peer cluster can either be enabled or disabled.
41 */
42 @InterfaceAudience.Private
43 public interface ReplicationPeers {
44
45 /**
46 * Initialize the ReplicationPeers interface.
47 * @throws KeeperException
48 */
49 void init() throws IOException, KeeperException;
50
51 /**
52 * Add a new remote slave cluster for replication.
53 * @param peerId a short that identifies the cluster
54 * @param clusterKey the concatenation of the slave cluster's:
55 * hbase.zookeeper.quorum:hbase.zookeeper.property.clientPort:zookeeper.znode.parent
56 */
57 void addPeer(String peerId, String clusterKey) throws IOException;
58
59 /**
60 * Removes a remote slave cluster and stops the replication to it.
61 * @param peerId a short that identifies the cluster
62 */
63 void removePeer(String peerId) throws IOException;
64
65 /**
66 * Restart the replication to the specified remote slave cluster.
67 * @param peerId a short that identifies the cluster
68 */
69 void enablePeer(String peerId) throws IOException;
70
71 /**
72 * Stop the replication to the specified remote slave cluster.
73 * @param peerId a short that identifies the cluster
74 */
75 void disablePeer(String peerId) throws IOException;
76
77 /**
78 * Get the replication status for the specified connected remote slave cluster.
79 * The value might be read from cache, so it is recommended to
80 * use {@link #getStatusOfPeerFromBackingStore(String)}
81 * if reading the state after enabling or disabling it.
82 * @param peerId a short that identifies the cluster
83 * @return true if replication is enabled, false otherwise.
84 */
85 boolean getStatusOfConnectedPeer(String peerId);
86
87 /**
88 * Get the replication status for the specified remote slave cluster, which doesn't
89 * have to be connected. The state is read directly from the backing store.
90 * @param peerId a short that identifies the cluster
91 * @return true if replication is enabled, false otherwise.
92 * @throws IOException Throws if there's an error contacting the store
93 */
94 boolean getStatusOfPeerFromBackingStore(String peerId) throws IOException;
95
96 /**
97 * Get a set of all connected remote slave clusters.
98 * @return set of peer ids
99 */
100 Set<String> getConnectedPeers();
101
102 /**
103 * List the cluster keys of all remote slave clusters (whether they are enabled/disabled or
104 * connected/disconnected).
105 * @return A map of peer ids to peer cluster keys
106 */
107 Map<String, String> getAllPeerClusterKeys();
108
109 /**
110 * List the peer ids of all remote slave clusters (whether they are enabled/disabled or
111 * connected/disconnected).
112 * @return A list of peer ids
113 */
114 List<String> getAllPeerIds();
115
116 /**
117 * Attempt to connect to a new remote slave cluster.
118 * @param peerId a short that identifies the cluster
119 * @return true if a new connection was made, false if no new connection was made.
120 */
121 boolean connectToPeer(String peerId) throws IOException, KeeperException;
122
123 /**
124 * Disconnect from a remote slave cluster.
125 * @param peerId a short that identifies the cluster
126 */
127 void disconnectFromPeer(String peerId);
128
129 /**
130 * Returns all region servers from given connected remote slave cluster.
131 * @param peerId a short that identifies the cluster
132 * @return addresses of all region servers in the peer cluster. Returns an empty list if the peer
133 * cluster is unavailable or there are no region servers in the cluster.
134 */
135 List<ServerName> getRegionServersOfConnectedPeer(String peerId);
136
137 /**
138 * Get the timestamp of the last change in composition of a given peer cluster.
139 * @param peerId identifier of the peer cluster for which the timestamp is requested
140 * @return the timestamp (in milliseconds) of the last change to the composition of
141 * the peer cluster
142 */
143 long getTimestampOfLastChangeToPeer(String peerId);
144
145 /**
146 * Returns the UUID of the provided peer id.
147 * @param peerId the peer's ID that will be converted into a UUID
148 * @return a UUID or null if the peer cluster does not exist or is not connected.
149 */
150 UUID getPeerUUID(String peerId);
151
152 /**
153 * Returns the configuration needed to talk to the remote slave cluster.
154 * @param peerId a short that identifies the cluster
155 * @return the configuration for the peer cluster, null if it was unable to get the configuration
156 */
157 Configuration getPeerConf(String peerId) throws KeeperException;
158 }