diff --git a/td-agent/Rakefile b/td-agent/Rakefile
index 9c0ad718e..0373a687a 100644
--- a/td-agent/Rakefile
+++ b/td-agent/Rakefile
@@ -426,6 +426,18 @@ class BuildTask
     render_template(dest_path, template_file_path, config, {mode: 0755})
   end
 
+  def apply_ruby_patches
+    return if BUNDLED_RUBY_PATCHES.nil?
+    BUNDLED_RUBY_PATCHES.each do |patch|
+      patch_name, version_condition = patch
+      dependency = Gem::Dependency.new('', version_condition)
+      if dependency.match?('', BUNDLED_RUBY_VERSION)
+        patch_path = File.join(__dir__, "patches", patch_name)
+        sh("patch", "-p1", "--input=#{patch_path}")
+      end
+    end
+  end
+
   def build_ruby_from_source
     tarball = @download_task.file_ruby_source
     ruby_source_dir = tarball.sub(/\.tar\.gz$/, '')
@@ -439,6 +451,7 @@ class BuildTask
       "--disable-install-doc",
     ]
     cd(ruby_source_dir) do
+      apply_ruby_patches
       sh("./configure #{configure_opts.join(' ')}")
       sh("make", "install", "-j#{Etc.nprocessors}", "DESTDIR=#{STAGING_DIR}")
 
diff --git a/td-agent/config.rb b/td-agent/config.rb
index 9f113fabd..29917d3ef 100644
--- a/td-agent/config.rb
+++ b/td-agent/config.rb
@@ -13,6 +13,11 @@
 #BUNDLED_RUBY_VERSION = "2.7.0"
 #BUNDLED_RUBY_SOURCE_SHA256SUM = "8c99aa93b5e2f1bc8437d1bbbefd27b13e7694025331f77245d0c068ef1f8cbe"
 
+BUNDLED_RUBY_PATCHES = [
+  ["ruby-2.7/0001-Removed-the-old-executables-of-racc.patch",            ["~> 2.7.0"]],
+  ["ruby-2.7/0002-Fixup-a6864f6d2f39bcd1ff04516591cc18d4027ab186.patch", ["~> 2.7.0"]],
+]
+
 # https://rubyinstaller.org/downloads/ (7-ZIP ARCHIVES)
 BUNDLED_RUBY_INSTALLER_X64_VERSION = "2.4.9-1"
 BUNDLED_RUBY_INSTALLER_X64_SHA256SUM = "b822c5b87e8baf8526c07496efa8fce595a75c82c7ebe549448958116a4dcb91"
diff --git a/td-agent/patches/ruby-2.7/0001-Removed-the-old-executables-of-racc.patch b/td-agent/patches/ruby-2.7/0001-Removed-the-old-executables-of-racc.patch
new file mode 100644
index 000000000..968313d55
--- /dev/null
+++ b/td-agent/patches/ruby-2.7/0001-Removed-the-old-executables-of-racc.patch
@@ -0,0 +1,634 @@
+From a6864f6d2f39bcd1ff04516591cc18d4027ab186 Mon Sep 17 00:00:00 2001
+From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
+Date: Wed, 1 Jan 2020 07:42:42 +0900
+Subject: [PATCH 1/2] Removed the old executables of racc
+
+  [ruby-core:93516][Feature #15982]
+
+  https://github.com/ruby/racc/pull/123
+---
+ bin/racc2y     |  27 ----
+ bin/y2racc     |  27 ----
+ libexec/racc2y | 195 ----------------------------
+ libexec/y2racc | 339 -------------------------------------------------
+ 4 files changed, 588 deletions(-)
+ delete mode 100755 bin/racc2y
+ delete mode 100755 bin/y2racc
+ delete mode 100755 libexec/racc2y
+ delete mode 100755 libexec/y2racc
+
+diff --git a/bin/racc2y b/bin/racc2y
+deleted file mode 100755
+index a1e4352632..0000000000
+--- a/bin/racc2y
++++ /dev/null
+@@ -1,27 +0,0 @@
+-#!/usr/bin/env ruby
+-#
+-# This file was generated by RubyGems.
+-#
+-# The application 'racc' is installed as part of a gem, and
+-# this file is here to facilitate running it.
+-#
+-
+-require 'rubygems'
+-
+-version = ">= 0.a"
+-
+-if ARGV.first
+-  str = ARGV.first
+-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
+-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
+-    version = $1
+-    ARGV.shift
+-  end
+-end
+-
+-if Gem.respond_to?(:activate_bin_path)
+-load Gem.activate_bin_path('racc', 'racc2y', version)
+-else
+-gem "racc", version
+-load Gem.bin_path("racc", "racc2y", version)
+-end
+diff --git a/bin/y2racc b/bin/y2racc
+deleted file mode 100755
+index 023615f369..0000000000
+--- a/bin/y2racc
++++ /dev/null
+@@ -1,27 +0,0 @@
+-#!/usr/bin/env ruby
+-#
+-# This file was generated by RubyGems.
+-#
+-# The application 'racc' is installed as part of a gem, and
+-# this file is here to facilitate running it.
+-#
+-
+-require 'rubygems'
+-
+-version = ">= 0.a"
+-
+-if ARGV.first
+-  str = ARGV.first
+-  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
+-  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
+-    version = $1
+-    ARGV.shift
+-  end
+-end
+-
+-if Gem.respond_to?(:activate_bin_path)
+-load Gem.activate_bin_path('racc', 'y2racc', version)
+-else
+-gem "racc", version
+-load Gem.bin_path("racc", "y2racc", version)
+-end
+diff --git a/libexec/racc2y b/libexec/racc2y
+deleted file mode 100755
+index f88d73ed2c..0000000000
+--- a/libexec/racc2y
++++ /dev/null
+@@ -1,195 +0,0 @@
+-#!/usr/local/bin/ruby
+-#
+-# $Id$
+-#
+-# Copyright (c) 1999-2006 Minero Aoki
+-#
+-# This program is feee software.
+-# You can distribute/modify this program under the terms of
+-# the GNU LGPL, Lesser General Public License version 2.1.
+-# For details of the LGPL, see the file "COPYING".
+-#
+-
+-require 'racc/grammarfileparser'
+-require 'racc/info'
+-require 'optparse'
+-
+-def main
+-  @with_action = true
+-  with_header = false
+-  with_inner = false
+-  with_footer = false
+-  output = nil
+-  parser = OptionParser.new
+-  parser.banner = "Usage: #{File.basename($0)} [-AHIF] [-oFILENAME] GRAMMARFILE"
+-  parser.on('-o', '--output=FILENAME', 'output file name [<input>.yacc]') {|name|
+-    output = name
+-  }
+-  parser.on('-A', '--without-action', 'Does not include actions.') {
+-    @with_action = false
+-  }
+-  parser.on('-H', '--with-header', 'Includes header part.') {
+-    with_header = true
+-  }
+-  parser.on('-I', '--with-inner', 'Includes inner part.') {
+-    with_inner = true
+-  }
+-  parser.on('-F', '--with-footer', 'Includes footer part.') {
+-    with_footer = true
+-  }
+-  parser.on('--version', 'Prints version and quit.') {
+-    puts "racc2y version #{Racc::Version}"
+-    exit 0
+-  }
+-  parser.on('--copyright', 'Prints copyright and quit.') {
+-    puts Racc::Copyright
+-    exit 0
+-  }
+-  parser.on('--help', 'Prints this message and quit.') {
+-    puts parser.help
+-    exit 1
+-  }
+-  begin
+-    parser.parse!
+-  rescue OptionParser::ParseError => err
+-    $stderr.puts err.message
+-    $stderr.puts parser.help
+-    exit 1
+-  end
+-  if ARGV.empty?
+-    $stderr.puts "no input file"
+-    exit 1
+-  end
+-  unless ARGV.size == 1
+-    $stderr.puts "too many inputs"
+-    exit 1
+-  end
+-  input = ARGV[0]
+-
+-  begin
+-    result = Racc::GrammarFileParser.parse_file(input)
+-    result.grammar.init
+-    File.open(output || "#{input}.yacc", 'w') {|f|
+-      f.puts "/* generated from #{input} */"
+-      if with_header
+-        f.puts
+-        f.puts '%{'
+-        print_user_codes f, result.params.header
+-        f.puts '%}'
+-      end
+-      f.puts
+-      print_terminals f, result.grammar
+-      f.puts
+-      print_precedence_table f, precedence_table(result.grammar)
+-      f.puts
+-      f.puts '%%'
+-      print_grammar f, result.grammar
+-      f.puts '%%'
+-      if with_inner
+-        f.puts '/*---- inner ----*/'
+-        print_user_codes f, result.params.inner
+-      end
+-      if with_footer
+-        f.puts '/*---- footer ----*/'
+-        print_user_codes f, result.params.footer
+-      end
+-    }
+-  rescue SystemCallError => err
+-    $stderr.puts err.message
+-    exit 1
+-  end
+-end
+-
+-def print_terminals(f, grammar)
+-  init_indent = '%token'.size
+-  f.print '%token'
+-  columns = init_indent
+-  grammar.symboltable.each_terminal do |t|
+-    next unless t.terminal?
+-    next if t.dummy?
+-    next if t == grammar.symboltable.anchor
+-    next if t == grammar.symboltable.error
+-    unless t.value.kind_of?(String)
+-      if columns > 60
+-        f.puts
+-        f.print ' ' * init_indent
+-        columns = init_indent
+-      end
+-      columns += f.write(" #{yacc_symbol(t)}")
+-    end
+-  end
+-  f.puts
+-end
+-
+-def precedence_table(grammar)
+-  table = []
+-  grammar.symboltable.select {|sym| sym.precedence }.each do |sym|
+-    (table[sym.prec] ||= [sym.assoc]).push sym
+-  end
+-  table.compact
+-end
+-
+-def print_precedence_table(f, table)
+-  return if table.empty?
+-  f.puts '/* precedance table */'
+-  table.each do |syms|
+-    assoc = syms.shift
+-    f.printf '%%%-8s ', assoc.to_s.downcase
+-    f.puts syms.map {|s| yacc_symbol(s) }.join(' ')
+-  end
+-  f.puts
+-end
+-
+-def print_grammar(f, grammar)
+-  prev_target = nil
+-  indent = 10
+-  embactions = []
+-  grammar.each do |rule|
+-    if rule.target.dummy?
+-      embactions.push rule.action  unless rule.action.empty?
+-      next
+-    end
+-    if rule.target == prev_target
+-      f.print ' ' * indent, '|'
+-    else
+-      prev_target = rule.target
+-      f.printf "\n%-10s:", yacc_symbol(prev_target)
+-    end
+-    rule.symbols.each do |s|
+-      if s.dummy?   # target of dummy rule for embedded action
+-        f.puts
+-        print_action f, embactions.shift, indent
+-        f.print ' ' * (indent + 1)
+-      else
+-        f.print ' ', yacc_symbol(s)
+-      end
+-    end
+-    if rule.specified_prec
+-      f.print ' %prec ', yacc_symbol(rule.specified_prec)
+-    end
+-    f.puts
+-    unless rule.action.empty?
+-      print_action f, rule.action, indent
+-    end
+-  end
+-end
+-
+-def print_action(f, action, indent)
+-  return unless @with_action
+-  f.print ' ' * (indent + 4), "{\n"
+-  f.print ' ' * (indent + 6), action.source.text.strip, "\n"
+-  f.print ' ' * (indent + 4) , "}\n"
+-end
+-
+-def print_user_codes(f, srcs)
+-  return if srcs.empty?
+-  srcs.each do |src|
+-    f.puts src.text
+-  end
+-end
+-
+-def yacc_symbol(s)
+-  s.to_s.gsub('"', "'")
+-end
+-
+-main
+diff --git a/libexec/y2racc b/libexec/y2racc
+deleted file mode 100755
+index 7933f94153..0000000000
+--- a/libexec/y2racc
++++ /dev/null
+@@ -1,339 +0,0 @@
+-#!/usr/local/bin/ruby
+-#
+-# $Id$
+-#
+-# Copyright (c) 1999-2006 Minero Aoki
+-#
+-# This program is free software.
+-# You can distribute/modify this program under the terms of
+-# the GNU LGPL, Lesser General Public License version 2.1.
+-# For details of the GNU LGPL, see the file "COPYING".
+-#
+-
+-require 'racc/info'
+-require 'strscan'
+-require 'forwardable'
+-require 'optparse'
+-
+-def main
+-  @with_action = true
+-  @with_header = false
+-  @with_usercode = false
+-  cname = 'MyParser'
+-  input = nil
+-  output = nil
+-  parser = OptionParser.new
+-  parser.banner = "Usage: #{File.basename($0)} [-Ahu] [-c <classname>] [-o <filename>] <input>"
+-  parser.on('-o', '--output=FILENAME', 'output file name [<input>.racc]') {|name|
+-    output = name
+-  }
+-  parser.on('-c', '--classname=NAME', "Name of the parser class. [#{cname}]") {|name|
+-    cname = name
+-  }
+-  parser.on('-A', '--without-action', 'Does not include actions.') {
+-    @with_action = false
+-  }
+-  parser.on('-h', '--with-header', 'Includes header (%{...%}).') {
+-    @with_header = true
+-  }
+-  parser.on('-u', '--with-user-code', 'Includes user code.') {
+-    @with_usercode = true
+-  }
+-  parser.on('--version', 'Prints version and quit.') {
+-    puts "y2racc version #{Racc::Version}"
+-    exit 0
+-  }
+-  parser.on('--copyright', 'Prints copyright and quit.') {
+-    puts Racc::Copyright
+-    exit 0
+-  }
+-  parser.on('--help', 'Prints this message and quit.') {
+-    puts parser.help
+-    exit 1
+-  }
+-  begin
+-    parser.parse!
+-  rescue OptionParser::ParseError => err
+-    $stderr.puts err.message
+-    $stderr.puts parser.help
+-    exit 1
+-  end
+-  if ARGV.empty?
+-    $stderr.puts 'no input'
+-    exit 1
+-  end
+-  if ARGV.size > 1
+-    $stderr.puts 'too many input'
+-    exit 1
+-  end
+-  input = ARGV[0]
+-
+-  begin
+-    result = YaccFileParser.parse_file(input)
+-    File.open(output || "#{input}.racc", 'w') {|f|
+-      convert cname, result, f
+-    }
+-  rescue SystemCallError => err
+-    $stderr.puts err.message
+-    exit 1
+-  end
+-end
+-
+-def convert(classname, result, f)
+-  init_indent = 'token'.size
+-  f.puts %<# Converted from "#{result.filename}" by y2racc version #{Racc::Version}>
+-  f.puts
+-  f.puts "class #{classname}"
+-  unless result.terminals.empty?
+-    f.puts
+-    f.print 'token'
+-    columns = init_indent
+-    result.terminals.each do |t|
+-      if columns > 60
+-        f.puts
+-        f.print ' ' * init_indent
+-        columns = init_indent
+-      end
+-      columns += f.write(" #{t}")
+-    end
+-    f.puts
+-  end
+-  unless result.precedence_table.empty?
+-    f.puts
+-    f.puts 'preclow'
+-    result.precedence_table.each do |assoc, toks|
+-      f.printf "  %-8s %s\n", assoc, toks.join(' ')  unless toks.empty?
+-    end
+-    f.puts 'prechigh'
+-  end
+-  if result.start
+-    f.puts
+-    f.puts "start #{@start}"
+-  end
+-
+-  f.puts
+-  f.puts 'rule'
+-  texts = @with_action ? result.grammar : result.grammar_without_actions
+-  texts.each do |text|
+-    f.print text
+-  end
+-
+-  if @with_header and result.header
+-    f.puts
+-    f.puts '---- header'
+-    f.puts result.header
+-  end
+-  if @with_usercode and result.usercode
+-    f.puts
+-    f.puts '---- footer'
+-    f.puts result.usercode
+-  end
+-end
+-
+-class ParseError < StandardError; end
+-
+-class StringScanner_withlineno
+-  def initialize(src)
+-    @s = StringScanner.new(src)
+-    @lineno = 1
+-  end
+-
+-  extend Forwardable
+-  def_delegator "@s", :eos?
+-  def_delegator "@s", :rest
+-
+-  attr_reader :lineno
+-
+-  def scan(re)
+-    advance_lineno(@s.scan(re))
+-  end
+-
+-  def scan_until(re)
+-    advance_lineno(@s.scan_until(re))
+-  end
+-
+-  def skip(re)
+-    str = advance_lineno(@s.scan(re))
+-    str ? str.size : nil
+-  end
+-
+-  def getch
+-    advance_lineno(@s.getch)
+-  end
+-
+-  private
+-
+-  def advance_lineno(str)
+-    @lineno += str.count("\n") if str
+-    str
+-  end
+-end
+-
+-class YaccFileParser
+-
+-  Result = Struct.new(:terminals, :precedence_table, :start,
+-                      :header, :grammar, :usercode, :filename)
+-  class Result   # reopen
+-    def initialize
+-      super
+-      self.terminals = []
+-      self.precedence_table = []
+-      self.start = nil
+-      self.grammar = []
+-      self.header = nil
+-      self.usercode = nil
+-      self.filename = nil
+-    end
+-
+-    def grammar_without_actions
+-      grammar().map {|text| text[0,1] == '{' ? '{}' : text }
+-    end
+-  end
+-
+-  def YaccFileParser.parse_file(filename)
+-    new().parse(File.read(filename), filename)
+-  end
+-
+-  def parse(src, filename = '-')
+-    @result = Result.new
+-    @filename = filename
+-    @result.filename = filename
+-    s = StringScanner_withlineno.new(src)
+-    parse_header s
+-    parse_grammar s
+-    @result
+-  end
+-
+-  private
+-
+-  COMMENT = %r</\*[^*]*\*+(?:[^/*][^*]*\*+)*/>
+-  CHAR = /'((?:[^'\\]+|\\.)*)'/
+-  STRING = /"((?:[^"\\]+|\\.)*)"/
+-
+-  def parse_header(s)
+-    skip_until_percent s
+-    until s.eos?
+-      case
+-      when t = s.scan(/left/)
+-        @result.precedence_table.push ['left', scan_symbols(s)]
+-      when t = s.scan(/right/)
+-        @result.precedence_table.push ['right', scan_symbols(s)]
+-      when t = s.scan(/nonassoc/)
+-        @result.precedence_table.push ['nonassoc', scan_symbols(s)]
+-      when t = s.scan(/token/)
+-        list = scan_symbols(s)
+-        list.shift if /\A<(.*)>\z/ =~ list[0]
+-        @result.terminals.concat list
+-      when t = s.scan(/start/)
+-        @result.start = scan_symbols(s)[0]
+-      when s.skip(%r<(?:
+-            type | union | expect | thong | binary |
+-            semantic_parser | pure_parser | no_lines |
+-            raw | token_table
+-            )\b>x)
+-        skip_until_percent s
+-      when s.skip(/\{/)   # header (%{...%})
+-        str = s.scan_until(/\%\}/)
+-        str.chop!
+-        str.chop!
+-        @result.header = str
+-        skip_until_percent s
+-      when s.skip(/\%/)   # grammar (%%...)
+-        return
+-      else
+-        raise ParseError, "#{@filename}:#{s.lineno}: scan error"
+-      end
+-    end
+-  end
+-
+-  def skip_until_percent(s)
+-    until s.eos?
+-      s.skip /[^\%\/]+/
+-      next if s.skip(COMMENT)
+-      return if s.getch == '%'
+-    end
+-  end
+-
+-  def scan_symbols(s)
+-    list = []
+-    until s.eos?
+-      s.skip /\s+/
+-      if s.skip(COMMENT)
+-        ;
+-      elsif t = s.scan(CHAR)
+-        list.push t
+-      elsif t = s.scan(STRING)
+-        list.push t
+-      elsif s.skip(/\%/)
+-        break
+-      elsif t = s.scan(/\S+/)
+-        list.push t
+-      else
+-        raise ParseError, "#{@filename}:#{@lineno}: scan error"
+-      end
+-    end
+-    list
+-  end
+-
+-  def parse_grammar(s)
+-    buf = []
+-    until s.eos?
+-      if t = s.scan(/[^%'"{\/]+/)
+-        buf.push t
+-        break if s.eos?
+-      end
+-      if s.skip(/\{/)
+-        buf.push scan_action(s)
+-      elsif t = s.scan(/'(?:[^'\\]+|\\.)*'/) then buf.push t
+-      elsif t = s.scan(/"(?:[^"\\]+|\\.)*"/) then buf.push t
+-      elsif t = s.scan(COMMENT) then buf.push t
+-      elsif s.skip(/%prec\b/)   then buf.push '='
+-      elsif s.skip(/%%/)
+-        @result.usercode = s.rest
+-        break
+-      else
+-        buf.push s.getch
+-      end
+-    end
+-    @result.grammar = buf
+-  end
+-
+-  def scan_action(s)
+-    buf = '{'
+-    nest = 1
+-    until s.eos?
+-      if t = s.scan(%r<[^/{}'"]+>)
+-        buf << t
+-        break if s.eos?
+-      elsif t = s.scan(COMMENT)
+-        buf << t
+-      elsif t = s.scan(CHAR)
+-        buf << t
+-      elsif t = s.scan(STRING)
+-        buf << t
+-      else
+-        c = s.getch
+-        buf << c
+-        case c
+-        when '{'
+-          nest += 1
+-        when '}'
+-          nest -= 1
+-          return buf if nest == 0
+-        end
+-      end
+-    end
+-    $stderr.puts "warning: unterminated action in #{@filename}"
+-    buf
+-  end
+-
+-end
+-
+-unless Object.method_defined?(:funcall)
+-  class Object
+-    alias funcall __send__
+-  end
+-end
+-
+-
+-main
+-- 
+2.20.1
+
diff --git a/td-agent/patches/ruby-2.7/0002-Fixup-a6864f6d2f39bcd1ff04516591cc18d4027ab186.patch b/td-agent/patches/ruby-2.7/0002-Fixup-a6864f6d2f39bcd1ff04516591cc18d4027ab186.patch
new file mode 100644
index 000000000..a7eb5c9fa
--- /dev/null
+++ b/td-agent/patches/ruby-2.7/0002-Fixup-a6864f6d2f39bcd1ff04516591cc18d4027ab186.patch
@@ -0,0 +1,30 @@
+From 69731b248f12f52c3897584db914cdf04a8ce5ac Mon Sep 17 00:00:00 2001
+From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
+Date: Wed, 1 Jan 2020 07:53:27 +0900
+Subject: [PATCH 2/2] Fixup a6864f6d2f39bcd1ff04516591cc18d4027ab186
+
+---
+ lib/racc/racc.gemspec | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/lib/racc/racc.gemspec b/lib/racc/racc.gemspec
+index 6beb16c5b4..6ed031bfe1 100644
+--- a/lib/racc/racc.gemspec
++++ b/lib/racc/racc.gemspec
+@@ -16,11 +16,11 @@
+   s.email = [nil, "aaron@tenderlovemaking.com"]
+   s.homepage = "http://i.loveruby.net/en/projects/racc/"
+   s.licenses = ["MIT"]
+-  s.executables = ["racc", "racc2y", "y2racc"]
++  s.executables = ["racc"]
+   s.files = [
+     "COPYING", "ChangeLog", "DEPENDS", "Manifest.txt",
+     "README.ja.rdoc", "README.rdoc", "Rakefile", "TODO", "bin/racc",
+-    "bin/racc2y", "bin/y2racc", "ext/racc/MANIFEST",
++    "ext/racc/MANIFEST",
+     "ext/racc/com/headius/racc/Cparse.java", "ext/racc/cparse.c",
+     "ext/racc/depend", "ext/racc/extconf.rb", "fastcache/extconf.rb",
+     "fastcache/fastcache.c", "lib/racc.rb", "lib/racc/compat.rb",
+-- 
+2.20.1
+