A floating IP is a public, static IP address that is manually and often temporarily assigned to a device. TransIP's OpenStack implementation 'Public Cloud' utilizes floating IPs. It's possible to dynamically assign multiple floating IPs to a single OpenStack instance.
The most common use case for a floating IP is high availability of services. This is achievable because a floating IP address can easily be linked from one instance to another, for example, when an instance becomes unreachable.
By assigning a floating IP to a Virtual Machine (VM) or instances within a private network, it can accept connections from the internet. Of course, you can also assign a public IP address to a VM or instance to establish connections to the public internet. However, there are several important differences between a regular public IP address and a floating IP address:
-
Reusability, Portability, and High Availability (HA): One of the key differences is that a floating IP can be dynamically/reassigned to different Virtual Machines (VMs) or instances within the same cloud environment. This enables quick failovers and workload reshuffling without the need for IP configuration changes.
-
Isolation of Internal and External Traffic: Floating IPs allow VMs and instances to operate within a private network (i.e., without direct exposure to the internet), while remaining accessible via the floating IP address when needed. This adds an additional layer of security and network isolation.
- Flexibility: As floating IPs are not permanently bound to a specific VM, you can implement infrastructure changes more flexibly.