HBASE-23055 Alter hbase:meta

Make it so hbase:meta can be altered. TableState for hbase:meta
is kept in Master. State is in-memory transient so if  Master
fails, hbase:meta is ENABLED again. hbase:meta schema will be
bootstrapped from the filesystem. Changes to filesystem schema
are atomic so we should be ok if Master fails mid-edit (TBD)
Undoes a bunch of guards that prevented our being able to edit
hbase:meta. At minimmum, need to add in a bunch of WARNING.

TODO: Tests, more clarity around hbase:meta table state, and undoing
references to hard-coded hbase:meta regioninfo.

M hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java
 Throw illegal access exception if you try to use MetaTableAccessor
 getting state of the hbase:meta table.

M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java
 TODO: getTableState needs work in Connection implemetnations. Presumes
 state is in meta table for all tables. Uses MetaTableAccessor.
 TODO: More cleanup in here and more cleanup in async versions.

M hbase-client/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java
 Change isTableDisabled/Enabled implementation to ask the Master instead.
 This will give the Master's TableStateManager's opinion rather than
 client figuring it for themselves reading meta table direct.

M hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
 TODO: Cleanup in here. Go to master for state, not to meta.

M hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZKAsyncRegistry.java
 Logging cleanup.

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

M hbase-server/src/main/java/org/apache/hadoop/hbase/TableDescriptors.java
 Just cleanup.

M hbase-server/src/main/java/org/apache/hadoop/hbase/master/TableStateManager.java
 Add state holder for hbase:meta.
 Removed unused methods.

M hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java
 Shut down access.

M hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DisableTableProcedure.java
 Allow hbase:meta to be disabled.

M hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/EnableTableProcedure.java
 Allow hbase:meta to be enabled.

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

@@ -304,11 +304,18 @@ public static HRegionLocation getRegionLocation(Connection connection, byte[] re
    */
   public static HRegionLocation getRegionLocation(Connection connection, RegionInfo regionInfo)
       throws IOException {
-    byte[] row = getMetaKeyForRegion(regionInfo);
-    Get get = new Get(row);
+    return getRegionLocation(getCatalogFamilyRow(connection, regionInfo),
+        regionInfo, regionInfo.getReplicaId());
+  }
+
+  /**
+   * @return Return the {@link HConstants#CATALOG_FAMILY} row from hbase:meta.
+   */
+  public static Result getCatalogFamilyRow(Connection connection, RegionInfo ri)
+      throws IOException {
+    Get get = new Get(getMetaKeyForRegion(ri));
     get.addFamily(HConstants.CATALOG_FAMILY);
-    Result r = get(getMetaHTable(connection), get);
-    return getRegionLocation(r, regionInfo, regionInfo.getReplicaId());
+    return get(getMetaHTable(connection), get);
   }
 
   /** Returns the row key to use for this regionInfo */
@@ -1110,7 +1117,7 @@ public static RegionInfo getRegionInfo(final Result r, byte [] qualifier) {
   public static TableState getTableState(Connection conn, TableName tableName)
       throws IOException {
     if (tableName.equals(TableName.META_TABLE_NAME)) {
-      return new TableState(tableName, TableState.State.ENABLED);
+      throw new IllegalAccessError("Go to the Master to find hbase:meta table state, not here");
     }
     Table metaHTable = getMetaHTable(conn);
     Get get = new Get(tableName.getName()).addColumn(getTableFamily(), getTableStateColumn());
@@ -1138,7 +1145,8 @@ public static Map<TableName, TableState> getTableStates(Connection conn)
   }
 
   /**
-   * Updates state in META
+   * Updates state in META.
+   * Do not use. For internal use only.
    * @param conn connection to use
    * @param tableName table to look for
    */

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

@@ -1,4 +1,4 @@
-/**
+/*
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
@@ -45,6 +45,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.ReentrantLock;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.AuthUtil;
 import org.apache.hadoop.hbase.CallQueueTooBigException;
@@ -2057,6 +2058,9 @@ public NonceGenerator getNonceGenerator() {
 
   @Override
   public TableState getTableState(TableName tableName) throws IOException {
+    // TODO: This doesn't work if tablename is hbase:meta. Need to ask Master.
+    // Other problems with this implementation are that it presumes state is
+    // available in Master. Would be good to hide how state is kept.
     checkClosed();
     TableState tableState = MetaTableAccessor.getTableState(this, tableName);
     if (tableState == null) {

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

@@ -91,6 +91,7 @@
 import org.apache.hadoop.hbase.security.access.Permission;
 import org.apache.hadoop.hbase.security.access.ShadedAccessControlUtil;
 import org.apache.hadoop.hbase.security.access.UserPermission;
+import org.apache.hadoop.hbase.shaded.protobuf.ResponseConverter;
 import org.apache.hadoop.hbase.snapshot.ClientSnapshotDescriptionUtils;
 import org.apache.hadoop.hbase.snapshot.HBaseSnapshotException;
 import org.apache.hadoop.hbase.snapshot.RestoreSnapshotException;
@@ -948,22 +949,39 @@ public HTableDescriptor[] disableTables(Pattern pattern) throws IOException {
   @Override
   public boolean isTableEnabled(final TableName tableName) throws IOException {
     checkTableExists(tableName);
-    return executeCallable(new RpcRetryingCallable<Boolean>() {
+    // Go to the Master. It knows state of all tables.
+    return executeCallable(new MasterCallable<Boolean>(getConnection(),
+        getRpcControllerFactory()) {
       @Override
-      protected Boolean rpcCall(int callTimeout) throws Exception {
-        TableState tableState = MetaTableAccessor.getTableState(getConnection(), tableName);
-        if (tableState == null) {
+      protected Boolean rpcCall() throws Exception {
+        setPriority(tableName);
+        MasterProtos.GetTableStateRequest req = RequestConverter.buildGetTableStateRequest(tableName);
+        MasterProtos.GetTableStateResponse ret = master.getTableState(getRpcController(), req);
+        if (!ret.hasTableState() || ret.getTableState() == null) {
           throw new TableNotFoundException(tableName);
         }
-        return tableState.inStates(TableState.State.ENABLED);
+        return ret.getTableState().getState() == HBaseProtos.TableState.State.ENABLED;
       }
     });
   }
 
   @Override
   public boolean isTableDisabled(TableName tableName) throws IOException {
     checkTableExists(tableName);
-    return connection.isTableDisabled(tableName);
+    // Go to the Master. It knows state of all tables.
+    return executeCallable(new MasterCallable<Boolean>(getConnection(),
+        getRpcControllerFactory()) {
+      @Override
+      protected Boolean rpcCall() throws Exception {
+        setPriority(tableName);
+        MasterProtos.GetTableStateRequest req = RequestConverter.buildGetTableStateRequest(tableName);
+        MasterProtos.GetTableStateResponse ret = master.getTableState(getRpcController(), req);
+        if (!ret.hasTableState() || ret.getTableState() == null) {
+          throw new TableNotFoundException(tableName);
+        }
+        return ret.getTableState().getState() == HBaseProtos.TableState.State.DISABLED;
+      }
+    });
   }
 
   @Override
@@ -4357,5 +4375,4 @@ protected Boolean rpcCall() throws Exception {
     });
 
   }
-
 }

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

@@ -1,4 +1,4 @@
-/**
+/*
  * Copyright The Apache Software Foundation
  *
  * Licensed to the Apache Software Foundation (ASF) under one
@@ -23,6 +23,8 @@
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos;
 import org.apache.yetus.audience.InterfaceAudience;
 
+import java.io.Closeable;
+
 /**
  * A KeepAlive connection is not physically closed immediately after the close,
  *  but rather kept alive for a few minutes. It makes sense only if it is shared.
@@ -35,7 +37,7 @@
  * final user code. Hence it's package protected.
  */
 @InterfaceAudience.Private
-interface MasterKeepAliveConnection extends MasterProtos.MasterService.BlockingInterface {
+interface MasterKeepAliveConnection extends MasterProtos.MasterService.BlockingInterface, Closeable {
   // Do this instead of implement Closeable because closeable returning IOE is PITA.
   void close();
 }

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

@@ -663,9 +663,9 @@ public CompletableFuture<Void> disableTable(TableName tableName) {
 
   @Override
   public CompletableFuture<Boolean> isTableEnabled(TableName tableName) {
-    if (TableName.isMetaTableName(tableName)) {
-      return CompletableFuture.completedFuture(true);
-    }
+    // TODO: This doesn't work if tablename is hbase:meta. Need to ask Master.
+    // Other problems with this implementation are that it presumes state is
+    // available in Master. Would be good to hide how state is kept.
     CompletableFuture<Boolean> future = new CompletableFuture<>();
     addListener(AsyncMetaTableAccessor.getTableState(metaTable, tableName), (state, error) -> {
       if (error != null) {

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

@@ -1,4 +1,4 @@
-/**
+/*
  * 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
@@ -158,7 +158,8 @@ private void getMetaRegionLocation(CompletableFuture<RegionLocations> future,
           }
           Pair<RegionState.State, ServerName> stateAndServerName = getStateAndServerName(proto);
           if (stateAndServerName.getFirst() != RegionState.State.OPEN) {
-            LOG.warn("Meta region is in state " + stateAndServerName.getFirst());
+            LOG.warn("hbase:meta region (replicaId={}) is in state {}", replicaId,
+                stateAndServerName.getFirst());
           }
           locs[DEFAULT_REPLICA_ID] = new HRegionLocation(
             getRegionInfoForDefaultReplica(FIRST_META_REGIONINFO), stateAndServerName.getSecond());
@@ -173,7 +174,7 @@ private void getMetaRegionLocation(CompletableFuture<RegionLocations> future,
             LOG.warn("Failed to fetch " + path, error);
             locs[replicaId] = null;
           } else if (proto == null) {
-            LOG.warn("Meta znode for replica " + replicaId + " is null");
+            LOG.warn("hbase:meta znode for replica " + replicaId + " is null");
             locs[replicaId] = null;
           } else {
             Pair<RegionState.State, ServerName> stateAndServerName = getStateAndServerName(proto);
@@ -197,9 +198,8 @@ private void getMetaRegionLocation(CompletableFuture<RegionLocations> future,
   public CompletableFuture<RegionLocations> getMetaRegionLocation() {
     CompletableFuture<RegionLocations> future = new CompletableFuture<>();
     addListener(
-      zk.list(znodePaths.baseZNode)
-        .thenApply(children -> children.stream()
-          .filter(c -> c.startsWith(znodePaths.metaZNodePrefix)).collect(Collectors.toList())),
+      zk.list(znodePaths.baseZNode).thenApply(children -> children.stream().
+          filter(c -> znodePaths.isMetaZNodePrefix(c)).collect(Collectors.toList())),
       (metaReplicaZNodes, error) -> {
         if (error != null) {
           future.completeExceptionally(error);

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

@@ -1,4 +1,4 @@
-/**
+/*
  * 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
@@ -24,6 +24,7 @@
 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;
@@ -40,15 +41,24 @@ public class ZNodePaths {
   // TODO: Replace this with ZooKeeper constant when ZOOKEEPER-277 is resolved.
   public static final char ZNODE_PATH_SEPARATOR = '/';
 
-  public final static String META_ZNODE_PREFIX = "meta-region-server";
+  private static final String META_ZNODE_PREFIX = "meta-region-server";
   private static final String DEFAULT_SNAPSHOT_CLEANUP_ZNODE = "snapshot-cleanup";
 
   // base znode for this cluster
   public final String baseZNode;
-  // the prefix of meta znode, does not include baseZNode.
-  public final String metaZNodePrefix;
-  // znodes containing the locations of the servers hosting the meta replicas
-  public final ImmutableMap<Integer, String> metaReplicaZNodes;
+
+  /**
+   * The prefix of meta znode. Does not include baseZNode.
+   * Its a 'prefix' because meta replica id integer can be tagged on the end (if
+   * no number present, it is 'default' replica).
+   */
+  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
@@ -158,21 +168,21 @@ public String toString() {
   }
 
   /**
-   * Is the znode of any meta replica
-   * @param node
-   * @return true or false
+   * @return true if the znode is a meta region replica
    */
   public boolean isAnyMetaReplicaZNode(String node) {
-    if (metaReplicaZNodes.containsValue(node)) {
-      return true;
-    }
-    return false;
+    return this.metaReplicaZNodes.containsValue(node);
+  }
+
+  /**
+   * @return Meta Replica ZNodes
+   */
+  public Collection<String> getMetaReplicaZNodes() {
+    return this.metaReplicaZNodes.values();
   }
 
   /**
-   * Get the znode string corresponding to a replicaId
-   * @param replicaId
-   * @return znode
+   * @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
@@ -183,24 +193,21 @@ public String getZNodeForReplica(int replicaId) {
   }
 
   /**
-   * Parse the meta replicaId from the passed znode
+   * Parse the meta replicaId from the passed znode name.
    * @param znode the name of the znode, does not include baseZNode
    * @return replicaId
    */
   public int getMetaReplicaIdFromZnode(String znode) {
-    if (znode.equals(metaZNodePrefix)) {
-      return RegionInfo.DEFAULT_REPLICA_ID;
-    }
-    return Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
+    return znode.equals(metaZNodePrefix)?
+        RegionInfo.DEFAULT_REPLICA_ID:
+        Integer.parseInt(znode.substring(metaZNodePrefix.length() + 1));
   }
 
   /**
-   * Is it the default meta replica's znode
-   * @param znode the name of the znode, does not include baseZNode
-   * @return true or false
+   * @return True if meta znode.
    */
-  public boolean isDefaultMetaReplicaZnode(String znode) {
-    return metaReplicaZNodes.get(DEFAULT_REPLICA_ID).equals(znode);
+  public boolean isMetaZNodePrefix(String znode) {
+    return znode != null && znode.startsWith(this.metaZNodePrefix);
   }
 
   /**

hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java

@@ -1208,12 +1208,6 @@ public enum OperationStatusCode {
       HBCK_SIDELINEDIR_NAME, HBASE_TEMP_DIRECTORY, MIGRATION_NAME
     }));
 
-  /** Directories that are not HBase user table directories */
-  public static final List<String> HBASE_NON_USER_TABLE_DIRS =
-    Collections.unmodifiableList(Arrays.asList((String[])ArrayUtils.addAll(
-      new String[] { TableName.META_TABLE_NAME.getNameAsString() },
-      HBASE_NON_TABLE_DIRS.toArray())));
-
   /** Health script related settings. */
   public static final String HEALTH_SCRIPT_LOC = "hbase.node.health.script.location";
   public static final String HEALTH_SCRIPT_TIMEOUT = "hbase.node.health.script.timeout";

hbase-server/src/main/java/org/apache/hadoop/hbase/TableDescriptors.java

@@ -25,51 +25,39 @@
 
 /**
  * Get, remove and modify table descriptors.
- * Used by servers to host descriptors.
  */
 @InterfaceAudience.Private
 public interface TableDescriptors {
   /**
-   * @param tableName
    * @return TableDescriptor for tablename
-   * @throws IOException
    */
-  TableDescriptor get(final TableName tableName)
-      throws IOException;
+  TableDescriptor get(final TableName tableName) throws IOException;
 
   /**
    * Get Map of all NamespaceDescriptors for a given namespace.
    * @return Map of all descriptors.
-   * @throws IOException
    */
-  Map<String, TableDescriptor> getByNamespace(String name)
-  throws IOException;
+  Map<String, TableDescriptor> getByNamespace(String name) throws IOException;
 
   /**
    * Get Map of all TableDescriptors. Populates the descriptor cache as a
    * side effect.
    * Notice: the key of map is the table name which contains namespace. It was generated by
    * {@link TableName#getNameWithNamespaceInclAsString()}.
    * @return Map of all descriptors.
-   * @throws IOException
    */
   Map<String, TableDescriptor> getAll() throws IOException;
 
   /**
    * Add or update descriptor
    * @param htd Descriptor to set into TableDescriptors
-   * @throws IOException
    */
-  void add(final TableDescriptor htd)
-  throws IOException;
+  void add(final TableDescriptor htd) throws IOException;
 
   /**
-   * @param tablename
    * @return Instance of table descriptor or null if none found.
-   * @throws IOException
    */
-  TableDescriptor remove(final TableName tablename)
-  throws IOException;
+  TableDescriptor remove(final TableName tablename) throws IOException;
 
   /**
    * Enables the tabledescriptor cache