Prerequisites: service, clusterip
A clusterip is reachable only from inside the cluster. In a cloud, asking for a Service of type LoadBalancer makes the provider hand you a real external address. devata is on your home network with no cloud load balancer to call, so that job falls to MetalLB. It watches for LoadBalancer Services and hands each one a real address from a pool you give it on your LAN.
See it on the Grafana Service:
kubectl get svc -n monitoring kps-grafanaThe EXTERNAL-IP in your home range, 192.168.1.24x, is MetalLB’s doing; that is the address you actually type into a browser. The CLUSTER-IP beside it is still the internal one. So a single Service can carry both: an internal ClusterIP for in-cluster callers, and an external address from MetalLB for you on the LAN. MetalLB is what makes a bare-metal cluster feel like it has a cloud load balancer, without one existing.
Reference: MetalLB.