follow the steps in instrumentation docs for your nodejs applications hosted in 1st docker host

this shall send application data to 2nd docker host

OTEL_EXPORTER_OTLP_SPAN_ENDPOINT="http://<IP of SigNoz Backend>:55681/v1/trace" LS_SERVICE_NAME=<service name> npm start

the IP should be of 2nd dokcer host where signoz is installed