Arrange for elasticsearch to shutdown cleanly

Kubernetes initiates "graceful shutdown" by sending SIGTERM to pid 1.
The way the existing startup scripts worked, this signal arrived at
the shell wrapper, not elasticsearch, and the shell wrapper exited,
killing the container immediately.

Before this change:
    1 ?        Ss     0:00 /bin/sh -c /run.sh
    6 ?        S      0:00 /bin/bash /run.sh
   13 ?        S      0:00  \_ /bin/su -c /elasticsearch/bin/elasticsearch elasticsearch
   14 ?        Ss     0:00      \_ sh -c /elasticsearch/bin/elasticsearch
   15 ?        Sl    19:18          \_ /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java ... org.elasticsearch.bootstrap.Elasticsearch start

After this change:
    1 ?        Ssl    0:29 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java ... org.elasticsearch.bootstrap.Elasticsearch start

cluster/addons/fluentd-elasticsearch/es-controller.yaml

@@ -21,7 +21,7 @@ spec:
         kubernetes.io/cluster-service: "true"
     spec:
       containers:
-      - image: gcr.io/google_containers/elasticsearch:v2.4.1-1
+      - image: gcr.io/google_containers/elasticsearch:v2.4.1-2
         name: elasticsearch-logging
         resources:
           # need more cpu upon initialization, therefore burstable class

cluster/addons/fluentd-elasticsearch/es-image/Dockerfile

@@ -23,7 +23,7 @@ ENV DEBIAN_FRONTEND noninteractive
 ENV ELASTICSEARCH_VERSION 2.4.1
 
 RUN apt-get update \
-    && apt-get install -y curl \
+    && apt-get install -y curl gosu \
     && apt-get clean
 
 RUN set -x \
@@ -48,4 +48,4 @@ RUN useradd --no-create-home --user-group elasticsearch \
 VOLUME ["/data"]
 EXPOSE 9200 9300
 
-CMD /run.sh
+CMD ["/run.sh"]

cluster/addons/fluentd-elasticsearch/es-image/Makefile

@@ -16,7 +16,7 @@
 
 # The current value of the tag to be used for building and
 # pushing an image to gcr.io
-TAG = v2.4.1-1
+TAG = v2.4.1-2
 
 build:	elasticsearch_logging_discovery
 	docker build --pull -t gcr.io/google_containers/elasticsearch:$(TAG) .

cluster/addons/fluentd-elasticsearch/es-image/run.sh

@@ -25,4 +25,4 @@ export MINIMUM_MASTER_NODES=${MINIMUM_MASTER_NODES:-2}
 
 chown -R elasticsearch:elasticsearch /data
 
-/bin/su -c /elasticsearch/bin/elasticsearch elasticsearch
+exec gosu elasticsearch /elasticsearch/bin/elasticsearch