diff --git a/.circleci/config.yml b/.circleci/config.yml
index b90744d..6c1bb2a 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -39,7 +39,7 @@ jobs:
       - run:
           name: Run unit tests
           command: |
-            rake test -t -v
+            bundle exec rake test -t -v
 
   func_test_master:
     docker:
diff --git a/Gemfile.lock b/Gemfile.lock
index 109645e..bb3ddff 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,67 +1,74 @@
 PATH
   remote: .
   specs:
-    fluent-plugin-kubernetes-metrics (1.1.0)
-      fluentd (~> 1.4.0)
-      kubeclient (~> 4.2.2)
-      multi_json (~> 1.13.1)
-      oj (~> 3.7.9)
+    fluent-plugin-kubernetes-metrics (1.1.2)
+      fluentd (~> 1.9.1)
+      kubeclient (~> 4.6.0)
+      multi_json (~> 1.14.1)
+      oj (~> 3.10.2)
 
 GEM
   remote: https://rubygems.org/
   specs:
     addressable (2.6.0)
       public_suffix (>= 2.0.2, < 4.0)
-    cool.io (1.5.3)
+    concurrent-ruby (1.1.5)
+    cool.io (1.6.0)
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
-    dig_rb (1.0.1)
     docile (1.3.1)
-    domain_name (0.5.20180417)
+    domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
-    fluentd (1.4.0)
+    ffi (1.12.2)
+    ffi-compiler (1.0.1)
+      ffi (>= 1.0.0)
+      rake
+    fluentd (1.9.1)
       cool.io (>= 1.4.5, < 2.0.0)
-      dig_rb (~> 1.0.0)
       http_parser.rb (>= 0.5.1, < 0.7.0)
-      msgpack (>= 0.7.0, < 2.0.0)
+      msgpack (>= 1.3.1, < 2.0.0)
       serverengine (>= 2.0.4, < 3.0.0)
       sigdump (~> 0.2.2)
       strptime (>= 0.2.2, < 1.0.0)
-      tzinfo (~> 1.0)
+      tzinfo (>= 1.0, < 3.0)
       tzinfo-data (~> 1.0)
       yajl-ruby (~> 1.0)
     hashdiff (0.3.8)
-    http (3.3.0)
+    http (4.3.0)
       addressable (~> 2.3)
       http-cookie (~> 1.0)
-      http-form_data (~> 2.0)
-      http_parser.rb (~> 0.6.0)
+      http-form_data (~> 2.2)
+      http-parser (~> 1.2.0)
+    http-accept (1.7.0)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
-    http-form_data (2.1.1)
+    http-form_data (2.2.0)
+    http-parser (1.2.1)
+      ffi-compiler (>= 1.0, < 2.0)
     http_parser.rb (0.6.0)
     json (2.1.0)
-    kubeclient (4.2.2)
-      http (~> 3.0)
+    kubeclient (4.6.0)
+      http (>= 3.0, < 5.0)
       recursive-open-struct (~> 1.0, >= 1.0.4)
       rest-client (~> 2.0)
-    mime-types (3.2.2)
+    mime-types (3.3.1)
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2018.0812)
-    msgpack (1.2.7)
-    multi_json (1.13.1)
+    mime-types-data (3.2019.1009)
+    msgpack (1.3.1)
+    multi_json (1.14.1)
     netrc (0.11.0)
-    oj (3.7.9)
+    oj (3.10.2)
     power_assert (1.1.3)
     public_suffix (3.0.3)
     rake (12.3.2)
     recursive-open-struct (1.1.0)
-    rest-client (2.0.2)
+    rest-client (2.1.0)
+      http-accept (>= 1.7.0, < 2.0)
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
     safe_yaml (1.0.4)
-    serverengine (2.1.0)
+    serverengine (2.2.1)
       sigdump (~> 0.2.2)
     sigdump (0.2.4)
     simplecov (0.16.1)
@@ -72,14 +79,13 @@ GEM
     strptime (0.2.3)
     test-unit (3.3.0)
       power_assert
-    thread_safe (0.3.6)
-    tzinfo (1.2.5)
-      thread_safe (~> 0.1)
-    tzinfo-data (1.2018.9)
+    tzinfo (2.0.1)
+      concurrent-ruby (~> 1.0)
+    tzinfo-data (1.2019.3)
       tzinfo (>= 1.0.0)
     unf (0.1.4)
       unf_ext
-    unf_ext (0.0.7.5)
+    unf_ext (0.0.7.6)
     webmock (3.5.1)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
@@ -90,12 +96,12 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  bundler (~> 2.0.0)
+  bundler (~> 2.0)
   fluent-plugin-kubernetes-metrics!
-  rake (~> 12.3.2)
+  rake (~> 12.0)
   simplecov (~> 0.16.1)
   test-unit (~> 3.3.0)
   webmock (~> 3.5.1)
 
 BUNDLED WITH
-   2.0.1
+   2.1.4
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 5e7dbf0..65bffa4 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -19,14 +19,14 @@ USER root
 COPY *.gem /tmp/
 COPY licenses /licenses
 
-RUN gem install -N fluentd:1.4.0 \
-       fluent-plugin-prometheus:1.3.0 \
-       fluent-plugin-record-modifier:2.0.1 \
+RUN gem install -N fluentd:1.9.1 \
+       fluent-plugin-prometheus:1.7.0 \
+       fluent-plugin-record-modifier:2.1.0 \
        fluent-plugin-splunk-hec:${VERSION} \
-       oj:3.7.9 \
-       multi_json:1.13.1 \
-       bigdecimal:1.4.3 \
-       kubeclient:4.3.0 && \
+       oj:3.10.2 \
+       multi_json:1.14.1 \
+       bigdecimal:2.0.0 \
+       kubeclient:4.6.0 && \
     gem install -N /tmp/*.gem
 
 RUN groupadd -r $FLUENT_USER && \
diff --git a/docker/build.sh b/docker/build.sh
index b24b56f..47ecfce 100755
--- a/docker/build.sh
+++ b/docker/build.sh
@@ -8,7 +8,7 @@ bundle update --bundler
 bundle install
 
 # Build Gem
-rake build -t -v
+bundle exec rake build -t -v
 cp pkg/fluent-plugin-kubernetes-metrics-*.gem docker
 
 # Build Docker Image
diff --git a/fluent-plugin-kubernetes-metrics.gemspec b/fluent-plugin-kubernetes-metrics.gemspec
index 1edefa5..d9d8fd5 100644
--- a/fluent-plugin-kubernetes-metrics.gemspec
+++ b/fluent-plugin-kubernetes-metrics.gemspec
@@ -17,13 +17,13 @@ Gem::Specification.new do |spec|
   spec.executables   = files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.test_files    = test_files
   spec.require_paths = ['lib']
-  spec.add_development_dependency 'bundler', '~> 2.0.0'
-  spec.add_development_dependency 'rake', '~> 12.3.2'
+  spec.add_development_dependency 'bundler', '~> 2.0'
+  spec.add_development_dependency 'rake', '~> 12.0'
   spec.add_development_dependency 'simplecov', '~> 0.16.1'
   spec.add_development_dependency 'test-unit', '~> 3.3.0'
   spec.add_development_dependency 'webmock', '~> 3.5.1'
-  spec.add_runtime_dependency 'fluentd', '~> 1.4.0'
-  spec.add_runtime_dependency 'kubeclient', '~> 4.2.2'
-  spec.add_runtime_dependency 'multi_json', '~> 1.13.1'
-  spec.add_runtime_dependency 'oj', '~> 3.7.9'
+  spec.add_runtime_dependency 'fluentd', '~> 1.9.1'
+  spec.add_runtime_dependency 'kubeclient', '~> 4.6.0'
+  spec.add_runtime_dependency 'multi_json', '~> 1.14.1'
+  spec.add_runtime_dependency 'oj', '~> 3.10.2'
 end