VirtualServiceUnreachableRule

This message occurs when a virtual service contains a match rule that will never be used because a previous rule specifies the same match. It also occurs when there is more than one rule without any match at all.

Example

You will receive this message:

Warning [IST0130] (VirtualService sample-foo-cluster01.default) VirtualService rule #1 not used (only the last rule can have no matches).

when your cluster has the following virtual service:

apiVersion: networking.istio.io/v1
kind: VirtualService
metadata:
  name: sample-foo-cluster01
  namespace: foo
spec:
  hosts:
  - sample.foo.svc.cluster.local
  http:
  - fault:
      delay:
        fixedDelay: 5s
        percentage:
          value: 100
    route:
    - destination:
        host: sample.foo.svc.cluster.local
  - mirror:
      host: sample.bar.svc.cluster.local
    route:
    - destination:
        host: sample.bar.svc.cluster.local
        subset: v1

In this example, the virtual service specifies both a fault and a mirror. Having both is allowed, but they must be in the same route entry. Here the user has used two different http route entries (one for each -), the first overrides the second.

How to resolve

When you have an http with no match, there can only be one http route. In this case, removing the "-" before mirror indicates there is a single matchless route that both injects a fault and mirrors, not one route that faults and one that mirrors.

Be careful with YAML formatting when setting up complex routing.

Re-order your routes so that the most specific ones are first. Place ‘catch all’ routes at the end.