diff --git a/app/models/fluentd/agent/common.rb b/app/models/fluentd/agent/common.rb
index 781aadf..1e3105a 100644
--- a/app/models/fluentd/agent/common.rb
+++ b/app/models/fluentd/agent/common.rb
@@ -57,13 +57,16 @@ class Fluentd
         extra_options[:config_file] || self.class.default_options[:config_file]
       end
 
+
+      # define these methods on each Agent class
+
       %w(start stop restart).each do |method|
         define_method(method) do
           raise NotImplementedError
         end
       end
 
-      %w(running? log config config_write config_append logged_errors log_tail configuration).each do |method|
+      %w(running? log config config_write config_append log_tail configuration).each do |method|
         define_method(method) do
           raise NotImplementedError
         end
diff --git a/app/models/fluentd/agent/local_common.rb b/app/models/fluentd/agent/local_common.rb
index 928c3e6..38c39ac 100644
--- a/app/models/fluentd/agent/local_common.rb
+++ b/app/models/fluentd/agent/local_common.rb
@@ -1,11 +1,6 @@
 class Fluentd
   class Agent
     module LocalCommon
-      def pid
-        return unless File.exists?(pid_file)
-        File.read(pid_file).to_i rescue nil
-      end
-
       def running?
         begin
           pid && Process.kill(0, pid)
@@ -35,6 +30,31 @@ class Fluentd
           f.write content
         end
       end
+      def log_tail(limit = nil)
+        limit = limit.to_i rescue 0
+        limit = limit.zero? ? Settings.default_log_tail_count : limit
+        io = File.open(log_file)
+        buf = []
+        reader = ::FileReverseReader.new(io)
+        reader.each_line do |line|
+          buf << line
+          break if buf.length >= limit
+        end
+        buf
+      end
+
+      def configuration
+        if File.exists? config_file
+          ::Fluentd::Agent::Configuration.new(config_file)
+        end
+      end
+
+      private
+
+      def pid
+        return unless File.exists?(pid_file)
+        File.read(pid_file).to_i rescue nil
+      end
 
       def logged_errors(&block)
         return [] unless File.exist?(log_file)
@@ -72,25 +92,6 @@ class Fluentd
       ensure
         io && io.close
       end
-
-      def log_tail(limit = nil)
-        limit = limit.to_i rescue 0
-        limit = limit.zero? ? Settings.default_log_tail_count : limit
-        io = File.open(log_file)
-        buf = []
-        reader = ::FileReverseReader.new(io)
-        reader.each_line do |line|
-          buf << line
-          break if buf.length >= limit
-        end
-        buf
-      end
-
-      def configuration
-        if File.exists? config_file
-          ::Fluentd::Agent::Configuration.new(config_file)
-        end
-      end
     end
   end
 end