Transferring a Floating IP Between Services

This tutorial shows how to transfer an existing floating IP from one Kubernetes LoadBalancer service to another — without releasing and reassigning the IP.

Use case: A new version of a service should be reachable under the same IP, e.g. during a blue/green deployment or a service rename.

Prerequisites

• An existing LoadBalancer service with an assigned floating IP
• kubectl access to the cluster

Step 1 — Get the current floating IP

kubectl get svc <old-service-name>

The floating IP is shown in the EXTERNAL-IP column. Alternatively:

kubectl get svc <old-service-name> -o jsonpath='{.metadata.annotations.loadbalancer\.openstack\.org/load-balancer-address}'

Note the IP for the following steps.

Step 2 — Reserve the floating IP on the old service

If the keep-floatingip annotation is not yet set, add it now:

kubectl annotate svc <old-service-name> \
  loadbalancer.openstack.org/keep-floatingip="true"

Step 3 — Delete the old service

kubectl delete svc <old-service-name>

The load balancer in OpenStack is removed, but the floating IP remains reserved.

Step 4 — Create the new service with the floating IP

In the new service manifest, reference the floating IP via spec.loadBalancerIP and the annotations:

apiVersion: v1
kind: Service
metadata:
  name: <new-service-name>
  annotations:
    loadbalancer.openstack.org/keep-floatingip: "true"
    loadbalancer.openstack.org/load-balancer-address: <FloatingIP>
spec:
  type: LoadBalancer
  loadBalancerIP: <FloatingIP>
  selector:
    app: <new-app-label>
  ports:
    - port: 80
      targetPort: 8080

kubectl apply -f <new-service>.yaml

Step 5 — Verify the assignment

kubectl get svc <new-service-name>

After 1–2 minutes, the floating IP appears in the EXTERNAL-IP column. The CCM may need a brief moment to provision the new load balancer and assign the IP.

Notes

• There will be a brief downtime between deleting the old service and the new service becoming ready.
• keep-floatingip: "true" should remain set on the new service to retain the IP on future deletions.
• If the IP is no longer known after deleting the old service, please open a support ticket in the customer portal.