Support for External Database Persistence of Lighty Configuration Datastore

[techprakashverma]

Question
This question is a follow-up to issue #2506.

Does Lighty provide support for persisting the configuration datastore using an external persistence mechanism (for example, relational database, or NoSQL database), instead of relying on Kubernetes ConfigMaps or in-memory storage?

If such support exists, could you please point to the relevant configuration options, modules, or documentation that describe how to enable and configure this type of persistence?

[ihrasko]

No, lighty.io and ODL in general does not support to use other databases instead of MDSAL out-of-the-box. In theory, it is possible but there is no implementation yet (known).

[techprakashverma]

It's related to #2506.

I have gone through Pekko/Akka, But I’m seeking more clarity on this topic. Could you kindly address the specific points listed below?

I am deploying lighty‑rnc‑app (via lighty‑rnc‑app‑aggregator and the Helm chart) in Kubernetes.

Using RESTCONF, I can successfully add a NETCONF device (example: node-1) and retrieve it while the pod is running. However, after restarting the pod, the configuration is lost.

My question:

1. Once a device (e.g., node-1) is created/added, in which file is this configuration stored?

2. What is the file name and file path inside the container where this data has persisted?

Pod terminal

/lighty-rnc $ ls -lrt
total 180
-rw-r--r-- 1 root root  1282 Dec  8 12:37 start-controller.sh
-rw-r--r-- 1 root root  3122 Dec  8 12:37 sampleCallhomeConfig.json
-rw-r--r-- 1 root root  9483 Dec  8 12:37 lighty-rnc-app-23.0.0-SNAPSHOT.jar
-rw-r--r-- 1 root root 91697 Dec  8 12:38 lighty-rnc-app-23.0.0-SNAPSHOT-javadoc.jar
-rwxr-xr-x 1 root root    59 Dec  8 12:38 entrypoint.sh
-rw-r--r-- 1 root root 11248 Dec  8 12:38 LICENSE
drwxr-xr-x 3 root root  4096 Dec  8 12:38 configuration
drwxr-xr-x 2 root root  4096 Dec  8 12:38 singlenode
drwxr-xr-x 2 root root 20480 Dec  8 12:38 lib
drwxrwxrwx 3 root root  4096 Jan 16 16:53 k8s-config
drwxrwxrwt 3 root root   100 Jan 16 16:53 keystore
drwxr-xr-x 3 rnc  rnc   4096 Jan 16 16:54 data
drwxr-xr-x 2 rnc  rnc   4096 Jan 16 16:54 segmented-journal
drwxr-xr-x 4 rnc  rnc   4096 Jan 16 16:54 state
drwxr-xr-x 3 rnc  rnc   4096 Jan 16 16:54 cache
drwxr-xr-x 3 rnc  rnc   4096 Jan 19 07:49 target

Reason for asking:
I would like to configure a PersistentVolumeClaim (PVC) to ensure that device configuration data persists across pod restarts. For this, I need to know the exact file name and file path inside the container where lighty‑rnc‑app writes its datastore, so that I can mount it to persistent storage.

I would be grateful for guidance regarding the persistence mechanism and the precise datastore file name and location.

[techprakashverma]

Since configmap solution cannot work in multi-site deployment from redundancy point of view.
Is there any other solution DB or otherwise which can support multi-site deployment?