This is example yaml file will create a nginx service and use octivia load balancer to expose service to public ip.

kubernetes_nginx_octivia.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: external-http-nginx-deployment
spec:
  replicas: 4
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
---
kind: Service
apiVersion: v1
metadata:
  name: external-http-nginx-service
  annotations:
    service.beta.kubernetes.io/openstack-internal-load-balancer: "false"
    loadbalancer.openstack.org/floating-network-id: "425c54bb-c4f2-41d6-a63c-a5c87257c929"
spec:
  selector:
    app: nginx
  type: LoadBalancer
  ports:
  - name: http
    port: 80
    targetPort: 80