TIS0202 - Specified Host Not Found in Service Registry

The specified host does not have a corresponding entry in the service registry (service, workload, or service entries).

Recommendation: Ensure Hosts Are Valid Entries in the Service Registry

To ensure routing is effective, verify that hosts specified in your Istio configurations are valid and exist in the service registry. Correct any typos, use FQDNs where necessary, or deploy missing services to the mesh.

Examples

1. VirtualService with Non-Existent Host

   apiVersion: networking.istio.io/v1beta1
   kind: VirtualService
   metadata:
     name: virtual-service-invalid-host
     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, resulting in failed routing.

2. DestinationRule with Invalid Host

   apiVersion: networking.istio.io/v1beta1
   kind: DestinationRule
   metadata:
     name: invalid-host-destination-rule
     namespace: example-namespace
   spec:
     host: "non-existent-service.example-namespace.svc.cluster.local"
     trafficPolicy:
       loadBalancer:
         simple: ROUND_ROBIN

   Explanation: The DestinationRule specifies a host non-existent-service.example-namespace.svc.cluster.local that is not found in the service registry, making the rule ineffective.

3. ServiceEntry Refers to a Non-Existent Internal Host

   apiVersion: networking.istio.io/v1beta1
   kind: ServiceEntry
   metadata:
     name: internal-service-entry
     namespace: example-namespace
   spec:
     hosts:
     - "non-existent.internal-service"
     location: MESH_INTERNAL
     ports:
     - number: 80
       name: http
       protocol: HTTP

   Explanation: The ServiceEntry specifies an internal host non-existent.internal-service that does not have a corresponding entry in the service registry, making the configuration invalid.

Recommendation

Correct the host to point to a valid service in this namespace or use a fully qualified domain name (FQDN) for services in other namespaces, or deploy the missing service to the mesh.

1. Correct the Hostname to a Valid Service

   Ensure that the host specified is correct and matches an existing service in the service registry.

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

2. Use an FQDN for Cross-Namespace Services

   If the target service is in another namespace, use a fully qualified domain name (FQDN).

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

3. Deploy the Missing Service

   If the specified host is intended to exist, deploy the corresponding service before applying the configuration.

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