HBASE-25103 Remove ZNodePaths.metaReplicaZNodes (#2464)

Signed-off-by: Huaxiang Sun <huaxiangsun@apache.com>

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZKConnectionRegistry.java

@@ -141,7 +141,7 @@ class ZKConnectionRegistry implements ConnectionRegistry {
     HRegionLocation[] locs = new HRegionLocation[metaReplicaZNodes.size()];
     MutableInt remaining = new MutableInt(locs.length);
     for (String metaReplicaZNode : metaReplicaZNodes) {
-      int replicaId = znodePaths.getMetaReplicaIdFromZnode(metaReplicaZNode);
+      int replicaId = znodePaths.getMetaReplicaIdFromZNode(metaReplicaZNode);
       String path = ZNodePaths.joinZNode(znodePaths.baseZNode, metaReplicaZNode);
       if (replicaId == DEFAULT_REPLICA_ID) {
         addListener(getAndConvert(path, ZKConnectionRegistry::getMetaProto), (proto, error) -> {

hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZNodePaths.java

@@ -17,22 +17,15 @@
  */
 package org.apache.hadoop.hbase.zookeeper;
 
-import static org.apache.hadoop.hbase.HConstants.DEFAULT_META_REPLICA_NUM;
 import static org.apache.hadoop.hbase.HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT;
-import static org.apache.hadoop.hbase.HConstants.META_REPLICAS_NUM;
 import static org.apache.hadoop.hbase.HConstants.SPLIT_LOGDIR_NAME;
 import static org.apache.hadoop.hbase.HConstants.ZOOKEEPER_ZNODE_PARENT;
-import static org.apache.hadoop.hbase.client.RegionInfo.DEFAULT_REPLICA_ID;
 
-import java.util.Collection;
-import java.util.Optional;
-import java.util.stream.IntStream;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.client.RegionInfo;
+import org.apache.hadoop.hbase.client.RegionReplicaUtil;
 import org.apache.yetus.audience.InterfaceAudience;
 
-import org.apache.hbase.thirdparty.com.google.common.collect.ImmutableMap;
-
 /**
  * Class that hold all the paths of znode for HBase.
  */
@@ -55,11 +48,6 @@ public class ZNodePaths {
    */
   private final String metaZNodePrefix;
 
-  /**
-   * znodes containing the locations of the servers hosting the meta replicas
-   */
-  private final ImmutableMap<Integer, String> metaReplicaZNodes;
-
   // znode containing ephemeral nodes of the regionservers
   public final String rsZNode;
   // znode containing ephemeral nodes of the draining regionservers
@@ -104,14 +92,7 @@ public class ZNodePaths {
 
   public ZNodePaths(Configuration conf) {
     baseZNode = conf.get(ZOOKEEPER_ZNODE_PARENT, DEFAULT_ZOOKEEPER_ZNODE_PARENT);
-    ImmutableMap.Builder<Integer, String> builder = ImmutableMap.builder();
     metaZNodePrefix = conf.get(META_ZNODE_PREFIX_CONF_KEY, META_ZNODE_PREFIX);
-    String defaultMetaReplicaZNode = ZNodePaths.joinZNode(baseZNode, metaZNodePrefix);
-    builder.put(DEFAULT_REPLICA_ID, defaultMetaReplicaZNode);
-    int numMetaReplicas = conf.getInt(META_REPLICAS_NUM, DEFAULT_META_REPLICA_NUM);
-    IntStream.range(1, numMetaReplicas)
-        .forEachOrdered(i -> builder.put(i, defaultMetaReplicaZNode + "-" + i));
-    metaReplicaZNodes = builder.build();
     rsZNode = joinZNode(baseZNode, conf.get("zookeeper.znode.rs", "rs"));
     drainingZNode = joinZNode(baseZNode, conf.get("zookeeper.znode.draining.rs", "draining"));
     masterAddressZNode = joinZNode(baseZNode, conf.get("zookeeper.znode.master", "master"));
@@ -142,7 +123,6 @@ public class ZNodePaths {
   public String toString() {
     return new StringBuilder()
         .append("ZNodePaths [baseZNode=").append(baseZNode)
-        .append(", metaReplicaZNodes=").append(metaReplicaZNodes)
         .append(", rsZNode=").append(rsZNode)
         .append(", drainingZNode=").append(drainingZNode)
         .append(", masterAddressZNode=").append(masterAddressZNode)
@@ -164,29 +144,15 @@ public class ZNodePaths {
         .append("]").toString();
   }
 
-  /**
-   * @return true if the znode is a meta region replica
-   */
-  public boolean isAnyMetaReplicaZNode(String node) {
-    return this.metaReplicaZNodes.containsValue(node);
-  }
-
-  /**
-   * @return Meta Replica ZNodes
-   */
-  public Collection<String> getMetaReplicaZNodes() {
-    return this.metaReplicaZNodes.values();
-  }
-
   /**
    * @return the znode string corresponding to a replicaId
    */
   public String getZNodeForReplica(int replicaId) {
-    // return a newly created path but don't update the cache of paths
+    if (RegionReplicaUtil.isDefaultReplica(replicaId)) {
-    // This is mostly needed for tests that attempt to create meta replicas
+      return joinZNode(baseZNode, metaZNodePrefix);
-    // from outside the master
+    } else {
-    return Optional.ofNullable(metaReplicaZNodes.get(replicaId))
+      return joinZNode(baseZNode, metaZNodePrefix + "-" + replicaId);
-        .orElseGet(() -> metaReplicaZNodes.get(DEFAULT_REPLICA_ID) + "-" + replicaId);
+    }
   }
 
   /**
@@ -198,7 +164,7 @@ public class ZNodePaths {
     // Extract the znode from path. The prefix is of the following format.
     // baseZNode + PATH_SEPARATOR.
     int prefixLen = baseZNode.length() + 1;
-    return getMetaReplicaIdFromZnode(path.substring(prefixLen));
+    return getMetaReplicaIdFromZNode(path.substring(prefixLen));
   }
 
   /**
@@ -206,7 +172,7 @@ public class ZNodePaths {
    * @param znode the name of the znode, does not include baseZNode
    * @return replicaId
    */
-  public int getMetaReplicaIdFromZnode(String znode) {
+  public int getMetaReplicaIdFromZNode(String znode) {
     return znode.equals(metaZNodePrefix)?
         RegionInfo.DEFAULT_REPLICA_ID:
         Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
@@ -220,17 +186,25 @@ public class ZNodePaths {
   }
 
   /**
-   * Returns whether the znode is supposed to be readable by the client and DOES NOT contain
+   * @return True is the fully qualified path is for meta location
+   */
+  public boolean isMetaZNodePath(String path) {
+    int prefixLen = baseZNode.length() + 1;
+    return path.length() > prefixLen && isMetaZNodePrefix(path.substring(prefixLen));
+  }
+
+  /**
+   * Returns whether the path is supposed to be readable by the client and DOES NOT contain
    * sensitive information (world readable).
    */
-  public boolean isClientReadable(String node) {
+  public boolean isClientReadable(String path) {
     // Developer notice: These znodes are world readable. DO NOT add more znodes here UNLESS
     // all clients need to access this data to work. Using zk for sharing data to clients (other
     // than service lookup case is not a recommended design pattern.
-    return node.equals(baseZNode) || isAnyMetaReplicaZNode(node) ||
+    return path.equals(baseZNode) || isMetaZNodePath(path) || path.equals(masterAddressZNode) ||
-      node.equals(masterAddressZNode) || node.equals(clusterIdZNode) || node.equals(rsZNode) ||
+      path.equals(clusterIdZNode) || path.equals(rsZNode) ||
       // /hbase/table and /hbase/table/foo is allowed, /hbase/table-lock is not
-      node.equals(tableZNode) || node.startsWith(tableZNode + "/");
+      path.equals(tableZNode) || path.startsWith(tableZNode + "/");
   }
 
   /**

hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterMetaBootstrap.java

@@ -92,7 +92,7 @@ class MasterMetaBootstrap {
     try {
       List<String> metaReplicaZnodes = zooKeeper.getMetaReplicaNodes();
       for (String metaReplicaZnode : metaReplicaZnodes) {
-        int replicaId = zooKeeper.getZNodePaths().getMetaReplicaIdFromZnode(metaReplicaZnode);
+        int replicaId = zooKeeper.getZNodePaths().getMetaReplicaIdFromZNode(metaReplicaZnode);
         if (replicaId >= numMetaReplicasConfigured) {
           RegionState r = MetaTableLocator.getMetaRegionState(zooKeeper, replicaId);
           LOG.info("Closing excess replica of meta region " + r.getRegion());

hbase-server/src/main/java/org/apache/hadoop/hbase/master/MetaRegionLocationCache.java

@@ -157,7 +157,7 @@ public class MetaRegionLocationCache extends ZKListener {
   }
 
   private void updateMetaLocation(String path, ZNodeOpType opType) {
-    if (!isValidMetaZNode(path)) {
+    if (!isValidMetaPath(path)) {
       return;
     }
     LOG.debug("Updating meta znode for path {}: {}", path, opType.name());
@@ -220,8 +220,8 @@ public class MetaRegionLocationCache extends ZKListener {
    * Helper to check if the given 'path' corresponds to a meta znode. This listener is only
    * interested in changes to meta znodes.
    */
-  private boolean isValidMetaZNode(String path) {
+  private boolean isValidMetaPath(String path) {
-    return watcher.getZNodePaths().isAnyMetaReplicaZNode(path);
+    return watcher.getZNodePaths().isMetaZNodePath(path);
   }
 
   @Override

hbase-server/src/main/java/org/apache/hadoop/hbase/master/zksyncer/ClientZKSyncer.java

@@ -207,7 +207,7 @@ public abstract class ClientZKSyncer extends ZKListener {
   /**
    * @return the znode(s) to watch
    */
-  abstract Collection<String> getNodesToWatch();
+  abstract Collection<String> getNodesToWatch() throws KeeperException;
 
   /**
    * Thread to synchronize znode data to client ZK cluster

hbase-server/src/main/java/org/apache/hadoop/hbase/master/zksyncer/MetaLocationSyncer.java

@@ -19,10 +19,12 @@
 package org.apache.hadoop.hbase.master.zksyncer;
 
 import java.util.Collection;
-
+import java.util.stream.Collectors;
 import org.apache.hadoop.hbase.Server;
 import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
+import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
 import org.apache.yetus.audience.InterfaceAudience;
+import org.apache.zookeeper.KeeperException;
 
 /**
  * Tracks the meta region locations on server ZK cluster and synchronize them to client ZK cluster
@@ -36,11 +38,13 @@ public class MetaLocationSyncer extends ClientZKSyncer {
 
   @Override
   boolean validate(String path) {
-    return watcher.getZNodePaths().isAnyMetaReplicaZNode(path);
+    return watcher.getZNodePaths().isMetaZNodePath(path);
   }
 
   @Override
-  Collection<String> getNodesToWatch() {
+  Collection<String> getNodesToWatch() throws KeeperException {
-    return watcher.getZNodePaths().getMetaReplicaZNodes();
+    return watcher.getMetaReplicaNodes().stream()
+      .map(znode -> ZNodePaths.joinZNode(watcher.getZNodePaths().baseZNode, znode))
+      .collect(Collectors.toList());
   }
 }

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java

@@ -37,14 +37,11 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
-
 import javax.security.auth.login.AppConfigurationEntry;
 import javax.security.auth.login.AppConfigurationEntry.LoginModuleControlFlag;
-
 import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.AuthUtil;
-import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.exceptions.DeserializationException;
 import org.apache.hadoop.hbase.security.Superusers;
@@ -78,6 +75,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.protobuf.InvalidProtocolBufferException;
+
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ReplicationProtos;
 
@@ -1861,9 +1859,7 @@ public final class ZKUtil {
       }
       sb.append("\nRegion server holding hbase:meta: "
         + MetaTableLocator.getMetaRegionLocation(zkw));
-      Configuration conf = HBaseConfiguration.create();
+      int numMetaReplicas = zkw.getMetaReplicaNodes().size();
-      int numMetaReplicas = conf.getInt(HConstants.META_REPLICAS_NUM,
-               HConstants.DEFAULT_META_REPLICA_NUM);
       for (int i = 1; i < numMetaReplicas; i++) {
         sb.append("\nRegion server holding hbase:meta, replicaId " + i + " "
                     + MetaTableLocator.getMetaRegionLocation(zkw, i));
@@ -2109,7 +2105,7 @@ public final class ZKUtil {
       " byte(s) of data from znode " + znode +
       (watcherSet? " and set watcher; ": "; data=") +
       (data == null? "null": data.length == 0? "empty": (
-          zkw.getZNodePaths().isMetaZNodePrefix(znode)?
+          zkw.getZNodePaths().isMetaZNodePath(znode)?
             getServerNameOrEmptyString(data):
           znode.startsWith(zkw.getZNodePaths().backupMasterAddressesZNode)?
             getServerNameOrEmptyString(data):