Ensure plugin installation works on Cloudron

Dockerfile

@@ -16,11 +16,11 @@ RUN apt-get update && \
     net-tools \
     iputils-ping \
     dnsutils \
-    openjdk-17-jdk
+    openjdk-21-jdk
 
 # Set Elasticsearch version
 ENV ELASTIC_VERSION=9.1.5
-ENV JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
+ENV JAVA_HOME=/usr/lib/jvm/java-21-openjdk-amd64
 
 # Create elasticsearch user and group
 RUN groupadd elasticsearch && \
@@ -39,6 +39,7 @@ RUN mkdir -p /app/data/{elasticsearch,logs,config,secrets,jdk/bin,run} && \
 
 # Copy configuration files
 COPY elasticsearch.yml /app/elasticsearch.yml
+COPY .env.template /app/.env.template
 COPY start.sh /app/start.sh
 COPY stop.sh /app/stop.sh
 
@@ -50,4 +51,4 @@ HEALTHCHECK --interval=15s --timeout=10s --start-period=120s --retries=5 \
     CMD curl -fs -u elastic:$(cat /app/data/secrets/elastic_password) http://localhost:9200/_cluster/health?pretty || exit 1
 
 # Command to run
-CMD ["/app/start.sh"] 
+CMD ["/app/start.sh"]