[es] Fix address binding for Swarm Mode

Author: itzg

elasticsearch/Dockerfile

@@ -15,8 +15,6 @@ EXPOSE 9200 9300
 
 ENV ES_HOME=/usr/share/elasticsearch-$ES_VERSION \
     DEFAULT_ES_USER=elasticsearch \
-    DISCOVER_TRANSPORT_IP=eth0 \
-    DISCOVER_HTTP_IP=eth0 \
     ES_JAVA_OPTS="-Xms1g -Xmx1g"
 
 RUN adduser -S -s /bin/sh $DEFAULT_ES_USER

elasticsearch/README.md

@@ -182,20 +182,16 @@ Using the Docker Compose file above, a value of `2` is appropriate when scaling
 
     docker-compose scale master=3
 
-## Auto transport/http discovery with Swarm Mode
+## Multiple Network Binding, such as Swarm Mode
 
-When using Docker Swarm mode (starting with 1.12), the overlay and ingress network interfaces are assigned
-multiple IP addresses. As a result, it creates confusion for the transport publish logic even when using
-the special value `_eth0_`.
+When using Docker Swarm mode the container is presented with multiple ethernet
+devices. By default, all global, routable IP addresses are configured for
+Elasticsearch to use as `network.host`.
 
-To resolve this, add
+That discovery can be overridden by providing a specific ethernet device name
+to `DISCOVER_TRANSPORT_IP` and/or `DISCOVER_HTTP_IP`, such as
 
     -e DISCOVER_TRANSPORT_IP=eth0
-
-replacing `eth0` with another interface within the container, if needed.
-
-The same can be done for publish/binding of the http module by adding:
-
     -e DISCOVER_HTTP_IP=eth2
 
 ## Heap size and other JVM options

elasticsearch/start

@@ -19,6 +19,11 @@ discoverIpFromLink() {
   OPTS="$OPTS -E $mode.host=$ip"
 }
 
+discoverAllGlobalIps() {
+  ips=`ipaddr show scope global|awk '$1 == "inet" { if (!match($2,"/32")) { gsub("/.*","",$2) ; addrs[length(addrs)] = $2 } } END { for (i in addrs) { if (i>0) printf "," ; printf addrs[i] } }'`
+  OPTS="$OPTS -E network.host=$ips"
+}
+
 setup_clustering() {
 
   if [ -n "$CLUSTER" ]; then
@@ -112,8 +117,13 @@ OPTS="$OPTS \
   -E transport.tcp.port=9300 \
   -E http.port=9200"
 
-discoverIpFromLink $DISCOVER_TRANSPORT_IP transport
-discoverIpFromLink $DISCOVER_HTTP_IP http
+discoverAllGlobalIps
+if [ "${DISCOVER_TRANSPORT_IP}" != "" ]; then
+  discoverIpFromLink $DISCOVER_TRANSPORT_IP transport
+fi
+if [ "${DISCOVER_HTTP_IP}" != "" ]; then
+  discoverIpFromLink $DISCOVER_HTTP_IP http
+fi
 
 setup_personality
 setup_clustering