You can specify a persistence setting with the parameters l4_persistence and l7_persistence in the NCP ConfigMap.

The available option for layer 4 persistence is source IP. The available options for layer 7 persistence are cookie and source IP. The default is <None>. For example,
   # Choice of persistence type for ingress traffic through L7 Loadbalancer.
   # Accepted values:
   # 'cookie'
   # 'source_ip'
   l7_persistence = cookie

   # Choice of persistence type for ingress traffic through L4 Loadbalancer.
   # Accepted values:
   # 'source_ip'
   l4_persistence = source_ip
Starting with NCP 3.1.2, for layer 7 persistence, you can also specify the name of the cookie.
    # Specify a custom cookie name for NSX default LB when l7_persistence type
    # is set to cookie. It has no effect if l7_persistence is not set.
    #cookie_name = <None>

For a Kubernetes LoadBalancer service, you can also specify sessionAffinity on the service spec to configure persistence behavior for the service if the global layer 4 persistence is turned off, that is, l4_persistence is set to <None>. If l4_persistence is set to source_ip, the sessionAffinity on the service spec can be used to customize the persistence timeout for the service. The default layer 4 persistence timeout is 10800 seconds (same as that specified in the Kubernetes documentation for services (https://kubernetes.io/docs/concepts/services-networking/service). All services with default persistence timeout will share the same NSX-T load balancer persistence profile. A dedicated profile will be created for each service with a non-default persistence timeout.

Note: If the backend service of an Ingress is a service of type LoadBalancer, then the layer 4 virtual server for the service and the layer 7 virtual server for the Ingress cannot have different persistence settings, for example, source_ip for layer 4 and cookie for layer 7. In such a scenario, the persistence settings for both virtual servers must be the same ( source_ip, cookie, or None), or one of them is None (then the other setting can be source_ip or cookie). An example of such a scenario:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: cafe-ingress
spec:
  rules:
  - host: cafe.example.com
    http:
      paths:
      - path: /tea
        backend:
          serviceName: tea-svc
          servicePort: 80
-----
apiVersion: v1
kind: Service
metadata:
  name: tea-svc <==== same as the Ingress backend above
  labels:
    app: tea
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: tcp
  selector:
    app: tea
  type: LoadBalancer