Set a new size for a deployment, replica set, replication controller, or stateful set. More information: https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#scale.
kubectl scale --replicas=number_of_replicas rs/replica_name
kubectl scale --replicas=number_of_replicas -f path/to/file.yml
kubectl scale --current-replicas=current_replicas --replicas=number_of_replicas deployment/deployment_name