diff --git a/Dockerfile.sample b/Dockerfile.sample
index db489e0..2d29b94 100644
--- a/Dockerfile.sample
+++ b/Dockerfile.sample
@@ -1,15 +1,19 @@
-FROM fluent/fluentd:v1.10-1
+FROM fluent/fluentd:v1.19-debian
 MAINTAINER YOUR_NAME <...@...>
 
 USER root
 
-RUN apk add --no-cache --update --virtual .build-deps \
-        sudo build-base ruby-dev \
- # customize following instruction as you wish
- && sudo gem install fluent-plugin-elasticsearch \
+RUN buildDeps="sudo make gcc g++ libc-dev" \
+ && apt-get update \
+ && apt-get install -y --no-install-recommends $buildDeps \
+ && gem install fluent-plugin-concat \
  && sudo gem sources --clear-all \
- && apk del .build-deps \
- && rm -rf /home/fluent/.gem/ruby/2.5.0/cache/*.gem
+ && SUDO_FORCE_REMOVE=yes \
+    apt-get purge -y --auto-remove \
+                  -o APT::AutoRemove::RecommendsImportant=false \
+                  $buildDeps \
+ && rm -rf /var/lib/apt/lists/* \
+ && rm -rf /tmp/* /var/tmp/* /usr/lib/ruby/gems/*/cache/*.gem
 
 COPY fluent.conf /fluentd/etc/
 COPY entrypoint.sh /bin/
diff --git a/HOWTOBUILD.md b/HOWTOBUILD.md
index ee62802..df8f037 100644
--- a/HOWTOBUILD.md
+++ b/HOWTOBUILD.md
@@ -35,38 +35,15 @@ Documentation of `fluent.conf` is available at [docs.fluentd.org][3].
 ### 3. Customize Dockerfile to install plugins (optional)
 
 You can install [Fluentd plugins][4] using Dockerfile.
-Sample Dockerfile installs `fluent-plugin-elasticsearch`.
+Sample Dockerfile installs `fluent-plugin-concat`.
 To add plugins, edit `Dockerfile` as following:
 
 About deprecated old images, see [DEPRECATED](DEPRECATED.md).
 
-#### Alpine version
-
-```Dockerfile
-FROM fluent/fluentd:v1.17-1
-
-# Use root account to use apk
-USER root
-
-# below RUN includes plugin as examples elasticsearch is not required
-# you may customize including plugins as you wish
-RUN apk add --no-cache --update --virtual .build-deps \
-        sudo build-base ruby-dev \
- && sudo gem install fluent-plugin-elasticsearch \
- && sudo gem sources --clear-all \
- && apk del .build-deps \
- && rm -rf /tmp/* /var/tmp/* /usr/lib/ruby/gems/*/cache/*.gem
-
-COPY fluent.conf /fluentd/etc/
-COPY entrypoint.sh /bin/
-
-USER fluent
-```
-
 #### Debian version
 
 ```Dockerfile
-FROM fluent/fluentd:v1.17-debian-1
+FROM fluent/fluentd:v1.19-debian
 
 # Use root account to use apt
 USER root
@@ -76,7 +53,7 @@ USER root
 RUN buildDeps="sudo make gcc g++ libc-dev" \
  && apt-get update \
  && apt-get install -y --no-install-recommends $buildDeps \
- && sudo gem install fluent-plugin-elasticsearch \
+ && sudo gem install fluent-plugin-concat \
  && sudo gem sources --clear-all \
  && SUDO_FORCE_REMOVE=yes \
     apt-get purge -y --auto-remove \
@@ -93,7 +70,7 @@ USER fluent
 
 #### Note
 
-These example run `apk add`/`apt-get install` to be able to install
+These example run `apt-get install` to be able to install
 Fluentd plugins which require native extensions (they are removed immediately
 after plugin installation).
 If you're sure that plugins don't include native extensions, you can omit it