X-IPLB-Instance
When OVHcloud's IP Load Balancing service routes a request, the X-IPLB-Instance unofficial response header identifies which specific load balancer node in the fleet handled the request.
Usage
OVHcloud's IP Load Balancing (IPLB) service routes traffic across a fleet of load balancer nodes. The X-IPLB-Instance header identifies which specific node in the fleet processed the incoming request before forwarding to the backend.
The value is a numeric instance ID unique to the load balancer within OVH's infrastructure. This node-level detail is useful when debugging routing inconsistencies or performance anomalies tied to a particular path through OVH's network. If two requests to the same origin produce different behavior, comparing X-IPLB-Instance values reveals whether they were handled by different nodes. The header works alongside X-IPLB-Request-Id, which identifies the specific request transaction rather than the node.
Values
Numeric instance identifier
The value is a positive integer identifying the specific IPLB node handling the request. Different values across requests to the same host indicate different load balancer nodes were used.
Example
A response from one OVH load balancer node carries its instance ID in the header.
X-IPLB-Instance: 52345
A different request routed through a different node in the same OVH infrastructure returns a different identifier.
X-IPLB-Instance: 58703
Both IPLB HTTP headers commonly appear together in responses, providing both the node identity and the request identifier.
X-IPLB-Instance: 51946
X-IPLB-Request-Id: 0003B5B7:07BF_0227E461:0050_67C14A5B_3A29E:0836