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Checking resources

Documentation/network/servicemesh/gateway-api/troubleshooting.rst

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This page guides you through the different mechanics of Gateway API and how to troubleshoot them.

Be sure to follow the Generic and Setup Verification steps from the :ref:Troubleshooting Ingress & Service Mesh page<troubleshooting_servicemesh>.

Checking resources


#. Check the Gateway resource

.. code-block:: shell-session

  $ kubectl get gateway -A
  NAMESPACE                   NAME                 CLASS    ADDRESS          PROGRAMMED   AGE
  website                     http-gateway         cilium   172.21.255.202   True         5h
  webshop                     tls-gateway          cilium   172.21.255.203   True         5h

The preceding command returns an overview of all the Gateways in the cluster. Check the following:

* Is the Gateway programmed? 

    A programmed Gateway means that Cilium prepared a configuration for it.
  
  * If the ``Programmed true`` indicator is missing, make sure that Gateway API is enabled in the Cilium configuration.

* Does the gateway have an address?

You can check the service with ``kubectl get service``. 
If the gateway has an address, it means that a LoadBalancer service is assigned to the gateway.
If no IP appears, you might be missing a LoadBalancer implementation.

* Is the class ``cilium``? 

Cilium only programs Gateways with the class ``cilium``.

* If the Gateway API resource type (``Gateway``, ``HTTPRoute``, etc.) is not found, make sure that the Gateway API CRDs are installed.

You can use ``kubectl describe gateway`` to investigate issues more thoroughly.

.. code-block:: shell-session

  $ kubectl describe gateway <name>

    Conditions:
      Message:               Gateway successfully scheduled
      Reason:                Accepted
      Status:                True
      Type:                  Accepted
      Message:               Gateway successfully reconciled
      Reason:                Programmed
      Status:                True
      Type:                  Programmed
      [...]
    Listeners:
      Attached Routes:  2
      Conditions:
        Message:               Listener Ready
        Reason:                Programmed
        Status:                True
        Type:                  Programmed
        Message:               Listener Accepted
        Reason:                Accepted
        Status:                True
        [...]

You can see the general status of the gateway as well as the status of the configured listeners.

Listener status displays the number of routes successfully attached to the listener.

You can see status conditions for both gateway and listener:

  * ``Accepted``: the Gateway configuration was accepted.
  * ``Programmed``: the Gateway configuration was programmed into Envoy.
  * ``ResolvedRefs``: all referenced secrets were found and have permission for use.

If any of these conditions are set to false, the ``Message`` and ``Reason`` fields give more information.

#. Check the HTTPRoute resource

When the Gateway is functional, you can check the routes to verify if they are configured correctly. The way to check route status is similar to checking the status of a gateway resource.

While these instructions are written for HTTPRoute, they also apply to other route types.

.. code-block:: shell-session

$ kubectl get httproute -A
NAMESPACE                 NAME              HOSTNAMES         AGE
website                   homepage          www.example.org   17m
webshop                   catalog-service                     17m
webshop                   cart-service                        17m

To get more information, enter kubectl describe httproute <name>.

.. code-block:: shell-session

$ kubectl describe httproute <name>
Status:
  Parents:
    Conditions:
      Last Transition Time:  2023-06-05T15:11:53Z
      Message:               Accepted HTTPRoute
      Observed Generation:   1
      Reason:                Accepted
      Status:                True
      Type:                  Accepted
      Last Transition Time:  2023-06-05T15:11:53Z
      Message:               Service reference is valid
      Observed Generation:   1
      Reason:                ResolvedRefs
      Status:                True
      Type:                  ResolvedRefs
    Controller Name:         io.cilium/gateway-controller
    Parent Ref:
      Group:  gateway.networking.k8s.io
      Kind:   Gateway
      Name:   same-namespace

Status lists the conditions that are relevant for the specific HTTPRoute. Conditions are listed by parent reference to the gateway. If you linked the route to multiple gateways, multiple entries appear. Conditions include Reason, Type, Status and Message. Type indicates the condition type, and Status indicates with a boolean whether the condition type is met. Optionally, Message gives you more information about the condition.

Notice the following condition types:

  • Accepted: The HTTPRoute configuration was correct and accepted.
  • ResolvedRefs: The referenced services were found and are valid references.

If any of these are set to false, you can get more information by looking at the Message and Reason fields.

#. Check Cilium Operator logs

The Cilium Operator logs may contain further debugging information. For example, if the required Custom Resource Definitions (CRDs) are not installed, an error will be logged:

.. code-block:: shell-session

$ kubectl logs -n kube-system deployments/cilium-operator | grep gateway
level=error msg="Required GatewayAPI resources are not found, please
refer to docs for installation instructions" error="customresourcedefinitions.apiextensions.k8s.io \"gatewayclasses.gateway.networking.k8s.io\" not found
customresourcedefinitions.apiextensions.k8s.io \"gateways.gateway.networking.k8s.io\" not found
customresourcedefinitions.apiextensions.k8s.io \"httproutes.gateway.networking.k8s.io\" not found
customresourcedefinitions.apiextensions.k8s.io \"referencegrants.gateway.networking.k8s.io\" not found
customresourcedefinitions.apiextensions.k8s.io \"grpcroutes.gateway.networking.k8s.io\" not found
customresourcedefinitions.apiextensions.k8s.io \"tlsroutes.gateway.networking.k8s.io\" not found" subsys=gateway-api

Common mistakes


.. include:: mistakes-warning.rst

  • The backend service does not exist.

    To verify whether the backend service was found, run kubectl describe httproute <name> and inspect the conditions field:

    .. code-block:: shell-session

      Parents:
        Conditions:
          Last Transition Time:  2023-06-06T13:55:10Z
          Message:               Service "backend" not found
          Observed Generation:   1
          Reason:                BackendNotFound
          Status:                False
          Type:                  ResolvedRefs
          Last Transition Time:  2023-06-06T13:55:10Z
          Message:               Accepted HTTPRoute
          Observed Generation:   1
          Reason:                Accepted
          Status:                True
          Type:                  Accepted
        Controller Name:         io.cilium/gateway-controller
    
  • The gateway specified under parentRefs does not exist.

    To verify whether the gateway was found, run kubectl describe httproute <name> and inspect the conditions field:

.. code-block:: shell-session

Parents: Conditions: Last Transition Time: 2023-06-06T13:56:40Z Message: Gateway.gateway.networking.k8s.io "my-gateway" not found Observed Generation: 2 Reason: InvalidHTTPRoute Status: False Type: Accepted

Underlying mechanics: a high level overview


A Cilium deployment has two parts that handle Gateway API resources: the Cilium agent and the Cilium operator.

The Cilium operator watches all Gateway API resources and verifies whether the resources are valid. If resources are valid, the operator marks them as accepted. That starts the process of translation into Cilium Envoy Configuration resources.

The Cilium agent then picks up the Cilium Envoy Configuration resources.

The Cilium agent uses the resources to supply the configuration to the built in Envoy or the Envoy DaemonSet. Envoy handles traffic.