Can I use a VIP without a cluster?

Short answer

No. A VIP is an address that is shared between two devices and passes to the other when the active device fails; for this reason, it can be defined only while Clustering Enabled is on. In a single-device setup, only Interface IP is offered as the Ip Type in the IP add form. On a single device, the same job is done by an additional Interface IP added to the interface: the vService listens on this address. The only difference of a VIP compared with an Interface IP is that it passes to the other device in a failure; since there is no device to pass to on a single device, this difference has no counterpart.

How Does It Work?

• For a VIP to work, an Interface IP pair (this device / peer device) over which the two devices monitor each other is required; the peer device's address can be entered only in the cluster configuration.
• In a single-device (Standalone) setup, the VIP option in the IP add form and the VIP Communication fields on the interface are not shown.
• From the vService's point of view, there is no listening difference between an Interface IP and a VIP; both are selected from the Frontend IP list.

What Is Done on a Single Device?

Need	What is done on a single device
A separate publishing address for the vService	An additional Interface IP is added to the interface and selected in the vService
The address should not change when a second device is added later	When the cluster is set up, this address is redefined as a VIP; the address in DNS can stay the same
The service continuing in a device failure	A cluster is set up with a second TR7, and the vServices are published on a VIP

The cluster is turned on with Clustering Enabled in the tab opened with the Edit button on the Settings → Device Management → HA Clustering & Sync screen and saved with Submit; after that, the configuration is synchronized automatically between the two devices by default (Manual Sync Mode off).

Common Misconceptions

• "Defining a VIP makes a single device redundant." Redundancy is provided with a second device; on a single device, there is no other device to take over the address in a failure.
• "A vService can listen only on a VIP." A vService can listen on every Interface IP defined on the device.
• "A VIP works differently in the cloud; a cluster is not required." In Azure too, a cluster must be set up for a VIP; the VIP transition is done through the cloud infrastructure's API (Azure VIP setup).

How it is done in the documentation

• Add IP Address (Standalone) · IP Type
• Add IP Address (Cluster) · The IP Types in Cluster Mode
• HA Clustering & Sync (Standalone) · Clustering Enabled

Related questions

• What is a VIP, and when is it needed?
• Is TR7 itself a single point of failure; how do I set up Load Balancer redundantly?
• How does a cluster work?