Synchronize opensearch config to a user-defined directory (#15307)

* Synchronize opensearch config to a user-defined directory (fixes #15223)

* fixed check naming

* fixed opensearch configuration location

* simplified Environment constructor

* point gc logs of datanodes opensearch to /tmp for now

* full dir sync for opensearch config

* Fixed full dir sync when removing non-empty dir

* simpified recursive directory deletion

data-node/src/main/java/org/graylog/datanode/process/OpensearchConfiguration.java

@@ -16,6 +16,8 @@
  */
 package org.graylog.datanode.process;
 
+import org.graylog.datanode.management.Environment;
+
 import java.nio.file.Path;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -24,6 +26,7 @@ import java.util.Map;
 public record OpensearchConfiguration(
         String opensearchVersion,
         Path opensearchDir,
+        Path opensearchConfigDir,
         int httpPort,
         int transportPort,
         String authUsername,
@@ -55,4 +58,10 @@ public record OpensearchConfiguration(
     private String toValuesList(List<String> values) {
         return String.join(",", values);
     }
+
+    public Environment getEnv() {
+        final Environment env = new Environment(System.getenv());
+        env.put("OPENSEARCH_PATH_CONF", opensearchConfigDir.resolve("opensearch").toAbsolutePath().toString());
+        return env;
+    }
 }