Add a setup script and according makefile target to upgrade ES keystore from older versions of java

Author: BendingBender

Makefile

@@ -24,6 +24,13 @@ endif
 keystore:		## Setup Elasticsearch Keystore, by initializing passwords, and add credentials defined in `keystore.sh`.
 	$(DOCKER_COMPOSE_COMMAND) -f docker-compose.setup.yml run --rm keystore
 
+upgrade-keystore:	## Upgrade Elasticsearch Keystore, which is necessary when upgrading to an Elasticsearch version that uses a newer Java version.
+	@if [ -n "$$($(DOCKER_COMPOSE_COMMAND) ps -q)" ]; then \
+		echo "Please stop all running containers before upgrading the keystore."; \
+		exit 1; \
+	fi
+	$(DOCKER_COMPOSE_COMMAND) -f docker-compose.setup.yml run --rm upgrade-keystore
+
 certs:		    ## Generate Elasticsearch SSL Certs.
 	$(DOCKER_COMPOSE_COMMAND) -f docker-compose.setup.yml run --rm certs
 

docker-compose.setup.yml

@@ -1,7 +1,7 @@
 version: '3.5'
 
 services:
-  keystore:
+  keystore: &keystore-service
     image: elastdocker/elasticsearch:${ELK_VERSION}
     build:
       context: elasticsearch/
@@ -15,6 +15,10 @@ services:
     environment:
       ELASTIC_PASSWORD: ${ELASTIC_PASSWORD}
 
+  upgrade-keystore:
+    <<: *keystore-service
+    command: bash /setup/upgrade-keystore.sh
+
   certs:
     image: elastdocker/elasticsearch:${ELK_VERSION}
     build:

setup/upgrade-keystore.sh

@@ -0,0 +1,25 @@
+# Exit on Error
+set -e
+
+KEYSTORE_TO_UPGRADE=/secrets/keystore/elasticsearch.keystore
+KEYSTORE_TO_UPGRADE_BACKUP=$KEYSTORE_TO_UPGRADE.pre-upgrade
+KEYSTORE_LOCATION_FOR_TOOL=/usr/share/elasticsearch/config/elasticsearch.keystore
+
+if [ -f $KEYSTORE_TO_UPGRADE_BACKUP ]; then
+    echo "A backup of a previous run of this script was found at $KEYSTORE_TO_UPGRADE_BACKUP. Aborting execution!"
+    echo "Please remove the backup file and run the script again if you're sure that you want to run the upgrade script again."
+    exit 1
+fi
+
+echo "=========== Upgrading Elasticsearch Keystore =========="
+
+cp $KEYSTORE_TO_UPGRADE $KEYSTORE_LOCATION_FOR_TOOL
+
+echo "Running elasticsearch-keystore upgrade"
+elasticsearch-keystore upgrade
+
+mv $KEYSTORE_TO_UPGRADE $KEYSTORE_TO_UPGRADE_BACKUP
+mv $KEYSTORE_LOCATION_FOR_TOOL $KEYSTORE_TO_UPGRADE
+
+echo "======= Keystore upgrade completed successfully ======="
+echo "Old keystore was backed up to $KEYSTORE_TO_UPGRADE_BACKUP"