In today’s fast paced environment, high availability and rapid failover is more crucial than ever. Whether you are running a production web application, a critical database, or an up-time demanding service, relying on a static IP tied to a single server is a vulnerability.
This is why you need floating IP addresses. Floating IPs are a static and public IP address that can be reassigned on need-basis within the same network or infrastructure. This flexibility makes it an essential tool for failover systems, load balancing, disaster recovery, and streamlined server upgrades.
In this guide, we shall discuss floating IPs in detail with the most common use cases, configuration, benefits, and limitations.
How Does A Floating IP Work?
Floating IPs act as a public facing IP address that can float between different backend servers or instances. It is not tied to a single machine, instead it is dynamically reassigned to any server in the same cloud network.
Here is a visual breakdown of how a floating IP work in failover scenarios:
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Common Use Cases for Floating IPs
A floating IP is a powerhouse of flexibility and continuity for network infrastructure. Here are some of the most common use cases:
- Load Balancing
In a load balancing architect, floating IPs can identify the load balancer that distributes traffic across multiple backend servers.
- How it works:
The floating IP remains static for clients, while the backend infrastructure scales dynamically. - Why it matters:
You can upgrade or scale backend services without changing the public-facing IP address.
Example:
Floating IPs are assigned to a reverse proxy, which distributes traffic to multiple app servers.
- Disaster Recovery
Floating IPs offer a quick way to recover from a failure by switching traffic to a backup system.
- How it works:
If your primary server crashes, you can reassign the floating IP to a secondary server. - Why it matters:
This minimizes downtime and avoids DNS propagation delays.
Example:
In some cases, a script or monitoring tool detects failure and reassigns the floating IP to a healthy standby node.
- Seamless Server Upgrades
When you need to scale your infrastructure, floating IPs allow a smooth transition.
- How it works:
You prepare a new server in the background, then reassign the floating IP to it once it’s ready. - Why it matters:
You can perform upgrades without disrupting users or changing DNS settings.
Example:
When you migrate CentOS 7 server to AlmaLinux 8 server and simply reassign the floating IP once the new system is configured.
Floating IP in Cloud Environments
| Cloud Provider | Feature Name | Description | Reassignable? | Typical Use Cases | CLI / Management Tool |
| AWS | Elastic IP | Static public IPv4 address that can be remapped between EC2 instances. | ✅ Yes | Failover, HA, persistent public IP | aws ec2 associate-address |
| OpenStack | Floating IP | Public IP mapped to a private IP via Neutron/Nova; supports reassignment. | ✅ Yes | External access, failover | openstack floating ip set |
| DigitalOcean | Floating IP | Public IP that can be moved between Droplets in the same datacenter. | ✅ Yes | HA, seamless server upgrade | doctl compute floating-ip-action |
| Google Cloud | Static External IP | Reserved IPs assignable to instances or load balancers. | ✅ Yes | Load balancing, persistent IP | Google Cloud Console / gcloud CLI |
| Microsoft Azure | Public IP (Standard) | Public IP assignable across VMs or frontends in the same region. | ✅ Yes | Internet-facing apps, scalable VMs | Azure Portal / az network public-ip |
How to Configure a Floating IP Address
Configuring floating IPs addresses mainly involve assigning the IP to a server or a load balancer and preparing your environment to handle failure or reassignment. The process varies based on the cloud provider or the network setup.
- Reserve or Allocate a Floating IP
Use your cloud provider’s portal or the CLI to reserve a static or a floating IP.
- Assign the Floating IP to a Primary Instance
Attach the IP address to a server that will initially handle the incoming traffic, make sure that the server’s firewall and network configuration accepts traffic or the floating IPs.
- Configure Your Application or Load Balancer
Bind the application or the load balancer to the floating IPs or listen to all the interfaces (0.0.0.0). If needed, adjust DNS records to identify the floating IPs.
- Set Up Failover or Reassignment
Create a script or use automation tools to reassign the floating IPs in case of failures. Test the failover process to ensure that you have minimal downtime.
Benefits of Using A Floating IP
Floating IPs have quite a few benefits, including:
- Due to high availability, users can easily reassign IPs to a standby server during downtime, ensuring minimal service disruption.
- Seamless upgrades due to high flexibility and scalability.
- Faster recovery leading to lesser downtime and quick rerouting of traffic for a healthy instance without needing to update the DNS records.
- Your public-facing IP remains unchanged, avoiding DNS propagation delays.
- Supports dynamic load balancing, server migrations, and scalable infrastructure setups.
Limitations and Considerations
| Limitation / Consideration | Details |
| Limited to Same Region / Zone | Many providers only allow IP reassignment within the same datacenter. |
| Not IPv6-Friendly | Most floating IPs are IPv4 only; IPv6 support may vary. |
| Manual Failover May Be Needed | Without automation, reassigning can take time and cause downtime. |
| Extra Costs | Some providers (like AWS) charge for unused or reassigned Elastic IPs. |
| Requires Proper Network Configuration | You may need to tweak firewall, routing, and interface settings manually. |
Wrapping Up – Are Floating IPs the Right Choice For You?
A floating IP is a powerful tool at your disposal if you want highly available and resilient systems with cloud environments. Whether you are managing failover scenarios or performing zero downtime upgrades, floating IPs give the right flexibility to move without disrupting services.
How does a floating IP work?
It “floats” between servers, allowing traffic to be rerouted to a standby system if the primary one fails, without DNS changes or downtime.
Do all cloud providers support floating IPs?
Most major providers do under different names—AWS calls them Elastic IPs, OpenStack uses Floating IPs, and DigitalOcean also offers Floating IPs.
Can I set up a floating IP address on my own server?
Yes, with the right network configuration and tools like keepalived or Pacemaker, you can implement floating IPs for failover in on-prem or hybrid environments.
