TIS1001 - Specified Host Not Found in Service Registry

The specified host does not have a corresponding entry in the service registry.

Recommendation: Ensure Host Exists in Service Registry

To prevent routing issues, ensure the specified host has a corresponding entry in the service registry by creating a Service, VirtualService, or ServiceEntry as appropriate.

Examples

1. VirtualService Referring to a Non-Existent Host

   apiVersion: networking.istio.io/v1beta1
   kind: VirtualService
   metadata:
     name: invalid-host-virtual-service
     namespace: example-namespace
   spec:
     hosts:
     - "unknown-service.example-namespace.svc.cluster.local"
     http:
     - route:
       - destination:
           host: "unknown-service.example-namespace.svc.cluster.local"

   Explanation: The VirtualService references a host unknown-service.example-namespace.svc.cluster.local that does not exist in the service registry. Without an existing entry for this host, Istio cannot route traffic correctly, resulting in failed communication.

Recommendation

Ensure there is a Service, VirtualService, or ServiceEntry matching the host.

1. Add a Matching Kubernetes Service

   If the host should represent a Kubernetes service, create the corresponding service definition.

   apiVersion: v1
   kind: Service
   metadata:
     name: unknown-service
     namespace: example-namespace
   spec:
     ports:
     - protocol: TCP
       port: 80
       targetPort: 8080
     selector:
       app: unknown-service

   Explanation: Adding a Service for unknown-service ensures that there is a matching entry in the service registry, enabling Istio to correctly route traffic to the workload.

2. Create a ServiceEntry for External Services

   If the host is meant to represent an external service, create a ServiceEntry to add it to the service registry.

   apiVersion: networking.istio.io/v1beta1
   kind: ServiceEntry
   metadata:
     name: external-service-entry
     namespace: example-namespace
   spec:
     hosts:
     - "external-service.com"
     location: MESH_EXTERNAL
     ports:
     - number: 80
       name: http
       protocol: HTTP

   Explanation: Creating a ServiceEntry allows Istio to understand how to route traffic to the external host, ensuring proper connectivity to services outside the mesh.