How to expose k8s service to port 80 without a LoadBalancer

You can configure an ingress for the same. However, you will need a domain pointed to your k8s cluster or etchosts entry for cluster ips.

Yes, your option here would be to set you container as privileged and give it access to hostNetwork and use hostPort. I would not recommend this for any production workload as it relies on privileged containers and is advised against in the Kubernetes best practices.

I have provided a working example below:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: hostport
  name: hostport
spec:
  replicas: 1
  selector:
    matchLabels:
      app: hostport
  template:
    metadata:
      labels:
        app: hostport
    spec:
      containers:
      - image: nginx:latest
        name: nginx
        securityContext:
          privileged: true
        ports:
          - name: http
            containerPort: 80
            hostPort: 80
      hostNetwork: true

You should then be able to access this deployment using:

curl <NODE_IP>:80

Note that because this is using the actual port of the host only the NODE_IP of a node running this pod will respond, unlike a nodeport service where traffic will be forwarded.

Hope this helps!