Nats Clustering not working as expected with NATS Server 2.10.17

[prateeeka-nadimpalli]

We are trying recently to shift from using NATS streaming to directly the NATS server. However, we are encountering issues with clustering configuration as it appears to be missing from our current setup.

NATS Server Version: 2.10.17
NATS Helm Version : 1.2.1
Current Configuration File(NATS server config file):
{
"http_port": 8222,
"lame_duck_duration": "30s",
"lame_duck_grace_period": "10s",
"pid_file": "/var/run/nats/nats.pid",
"port": 4222,
"server_name": $SERVER_NAME
}

Previous Configuration File(NATS streaming config file):

#########################

NATS Streaming Config

#########################
streaming {
id: test-cluster
ft_group_name: test-stan-ft-group

###############################

Store Config

###############################
store: "file"
dir: /data/stan/store

###############################

NATS Streaming Clustering

###############################
}

###############################################

Embedded NATS Config

###############################################

PID file shared with configuration reloader.

pid_file: "/var/run/nats/nats.pid"

###############

Monitoring

###############
http: 8222
server_name: $POD_NAME

###################################

NATS Full Mesh Clustering Setup

###################################
cluster {
port: 6222

routes = [
nats://test-0.test.default.svc:6222,
]
cluster_advertise: $CLUSTER_ADVERTISE

connect_retries: 30
}
max_payload: 15728640/

Issue : The current configuration file does not include any clustering details. Because of this connection from my app to NATS is failing as its trying to connect to cluster. I need to set up clustering for my NATS servers, but seems cluster details are not getting from service itself. Could you assist how can I set these configurations ?