HBASE-22765 add move_table_to_servers command in shell

hbase-shell/src/main/ruby/hbase/admin.rb

@@ -523,6 +523,48 @@ def move(encoded_region_name, server = nil)
       @admin.move(encoded_region_name.to_java_bytes, server ? server.to_java_bytes : nil)
     end
 
+    #----------------------------------------------------------------------------------------------
+    # Move regions of a table
+    def move_table_to_servers(table_name, host_or_servers = nil)
+      if table_name == nil
+        $stdout.puts "table_name can NOT be NULL"
+        return
+      end
+
+      table_regions = @admin.getRegions(TableName.valueOf(table_name))
+      if table_regions == nil || table_regions.size == 0
+        $stdout.puts "no regions found for table #{table_name}"
+        return
+      end
+      region_count = table_regions.size
+
+      if host_or_servers.nil? || host_or_servers.empty?
+        region_servers = getRegionServers
+        server_name_strs = []
+        for server in region_servers
+          server_name_strs << server.getServerName()
+        end
+        host_or_servers = server_name_strs
+      end
+
+      # If a string is passed, convert  it to an array
+      _host_or_servers =  host_or_servers.is_a?(Array) ?
+                              host_or_servers :
+                              java.util.Arrays.asList(host_or_servers)
+      server_names = getServerNames(_host_or_servers, true)
+
+      index = 0
+      while index < region_count
+        encoded_region_name = table_regions[index].getEncodedName
+        server_name = server_names[index % server_names.size].getServerName
+        index += 1
+        $stdout.puts "start moving #{index} / #{region_count} region #{encoded_region_name} of table : #{table_name} to server : #{server_name}"
+        # move one region to the server
+        @admin.move(Bytes.toBytes(encoded_region_name), Bytes.toBytes(server_name))
+      end
+      $stdout.puts "finish moving all #{region_count} regions"
+    end
+
     #----------------------------------------------------------------------------------------------
     # Merge two regions
     def merge_region(region_a_name, region_b_name, force)

hbase-shell/src/main/ruby/shell.rb

@@ -339,6 +339,7 @@ def help_footer
     flush
     major_compact
     move
+    move_table_to_servers
     split
     merge_region
     unassign

hbase-shell/src/main/ruby/shell/commands/move_table_to_servers.rb

@@ -0,0 +1,45 @@
+#
+#
+# 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.
+#
+
+module Shell
+  module Commands
+    class MoveTableToServers < Command
+      def help
+        return <<-EOF
+Move all regions of the table to a list of regionservers. All regions will be moved to the
+given regionservers evenly if the 'SERVER_NAME' or list is specified, or to all regionservers
+evenly if 'SERVER_NAME' or list is absent
+
+NOTE:
+A server name is its host, port plus startcode. For example:
+host187.example.com,60020,1289493121758
+Examples:
+
+  hbase> move_table_to_servers 'TABLENAME', ['SERVER_NAME1','SERVER_NAME2']
+  hbase> move_table_to_servers 'TABLENAME', 'SERVER_NAME'
+  hbase> move_table_to_servers 'TABLENAME'
+        EOF
+      end
+
+      def command(table_name, server_names = nil)
+        admin.move_table_to_servers(table_name, server_names)
+      end
+    end
+  end
+end

hbase-shell/src/test/ruby/hbase/admin_test.rb

@@ -176,6 +176,16 @@ def teardown
 
     #-------------------------------------------------------------------------------
 
+    define_test 'move table to regionserver' do
+      command(:move_table_to_servers, @test_name)
+      server_name = admin.getServerNames([], true)[0].getServerName()
+      command(:move_table_to_servers, @test_name, server_name)
+      command(:move_table_to_servers, @test_name, [server_name])
+      puts "move_table_to_servers success!"
+    end
+
+    #-------------------------------------------------------------------------------
+
     define_test "create should fail with non-string table names" do
       assert_raise(ArgumentError) do
         command(:create, 123, 'xxx')