Fix elasticsearch-data shutdown

The shutdown script for the elasticsearch-data container uses a trap
handler to run the steps outlined in the rolling restart procedure [0].
However, when trying to kill the elasticsearch process (step 3), the
script sends the TERM signal to itself.

The traps are handled recursively, causing the entire termination grace
period to be exhausted before the pod is finally removed.

This change updates the trap handler to terminate the child process(es)
instead, and wait for their completion.

0: https://www.elastic.co/guide/en/elasticsearch/reference/7.x/restart-cluster.html

Change-Id: I0c92ea5cce345cff951f044026a2179dcbd5a3e2

elasticsearch/Chart.yaml

@@ -15,7 +15,7 @@ apiVersion: v1
 appVersion: v7.6.2
 description: OpenStack-Helm ElasticSearch
 name: elasticsearch
-version: 0.2.14
+version: 0.2.15
 home: https://www.elastic.co/
 sources:
   - https://github.com/elastic/elasticsearch

elasticsearch/templates/bin/_elasticsearch.sh.tpl

@@ -133,7 +133,16 @@ function start_data_node () {
     # (The only side effect of not doing so is slower start up times. See flush documentation linked above)
 
     echo "Node ${NODE_NAME} is ready to shutdown"
-    kill -TERM 1
+
+    echo "Killing Elasticsearch background processes"
+    jobs -p | xargs -t -r kill -TERM
+    wait
+
+    # remove the trap handler
+    trap - TERM EXIT HUP INT
+
+    echo "Node ${NODE_NAME} shutdown is complete"
+    exit 0
   }
   trap drain_data_node TERM EXIT HUP INT
   wait

releasenotes/notes/elasticsearch.yaml

@@ -24,4 +24,5 @@ elasticsearch:
   - 0.2.12 Helm 3 - Fix Job labels
   - 0.2.13 Update htk requirements
   - 0.2.14 Fix cronjob rendering
+  - 0.2.15 Fix elasticsearch-data shutdown
 ...