message: set my_name as the hosts: setting when only one present, also set proper config setting name
diff: # See the License for the specific language governing permissions and
  # limitations under the License.
  -# This script writes out a mysql galera config using a list of newline seperated
  -# peer DNS names it accepts through stdin.
  -
  -# /etc/mysql is assumed to be a shared volume so we can modify my.cnf as required
  -# to keep the config up to date, without wrapping mysqld in a custom pid1.
  -# The config location is intentionally not /etc/mysql/my.cnf because the
  -# standard base image clobbers that location.
  -
  CFG=/usr/share/elasticsearch/config/elasticsearch.yml
  @@ -41,12 +33,12 @@ while read -ra LINE; do
  done
  if [ "${#PEERS[@]}" = 1 ]; then
  - ES_CLUSTER_ADDRESS=""
  + ES_CLUSTER_ADDRESS="$MY_NAME"
  else
  ES_CLUSTER_ADDRESS=$(join , "${PEERS[@]}")
  fi
  -echo ${ES_CLUSTER_ADDRESS} >> ${CFG}
  +echo "discovery.zen.ping.unicast.hosts: ${ES_CLUSTER_ADDRESS}" >> ${CFG}
  # don't need a restart, we're just writing the conf in case there's an
  # unexpected restart on the node.
  