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Troubleshooting Deployments on GKE

Help fixing problems on GKE and GCP

This guide helps diagnose and fix issues you may encounter with Kubeflow on Google Kubernetes Engine (GKE) and Google Cloud Platform (GCP).

Before you start

This guide covers troubleshooting specifically for Kubeflow deployments on GCP.

For more help, try the general Kubeflow troubleshooting guide.

Troubleshooting Cloud IAP

Here are some tips for troubleshooting Cloud IAP.

  • Make sure you are using HTTPS

DNS name not registered

This section provides troubleshooting information for problems creating a DNS entry for your ingress. The ingress is a K8s resource that creates a GCP loadbalancer to enable http(s) access to Kubeflow web services from outside the cluster. This section assumes you are using Cloud Endpoints and a DNS name of the following pattern

https://${DEPLOYMENT_NAME}.endpoints.${PROJECT}.cloud.goog

Symptoms:

  • When you access the the URL in Chrome you get the error: server IP address could not be found

  • nslookup for the domain name doesn’t return the IP address associated with the ingress

    nslookup ${DEPLOYMENT_NAME}.endpoints.${PROJECT}.cloud.goog
Server:   127.0.0.1
Address:  127.0.0.1#53

** server can't find ${DEPLOYMENT_NAME}.endpoints.${PROJECT}.cloud.goog: NXDOMAIN

Troubleshooting

  1. Check the cloudendpoints resource

    kubectl get cloudendpoints -o yaml ${DEPLOYMENT_NAME}
kubectl describe cloudendpoints ${DEPLOYMENT_NAME}
    • Check if there are errors indicating problems creating the endpoint

  2. The status of the cloudendpoints object will contain the cloud operation used to register the operation

    • For example

       status:
   config: ""
   configMapHash: ""
   configSubmit: operations/serviceConfigs.jlewi-1218-001.endpoints.cloud-ml-dev.cloud.goog:43fe6c6f-eb9c-41d0-ac85-b547fc3e6e38
   endpoint: jlewi-1218-001.endpoints.cloud-ml-dev.cloud.goog
   ingressIP: 35.227.243.83
   jwtAudiences: null
   lastAppliedSig: 4f3b903a06a683b380bf1aac1deca72792472429
   observedGeneration: 1
   stateCurrent: ENDPOINT_SUBMIT_PENDING

  • You can check the status of the operation by running:

    gcloud --project=${PROJECT} endpoints operations describe ${OPERATION}
    • Operation is everything after operations/ in the configSubmit field

404 Page Not Found When Accessing Central Dashboard

This section provides troubleshooting information for 404s, page not found, being return by the central dashboard which is served at

https://${KUBEFLOW_FQDN}/
  • KUBEFLOW_FQDN is your project’s OAuth web app URI domain name <name>.endpoints.<project>.cloud.goog
  • Since we were able to sign in this indicates the Ambassador reverse proxy is up and healthy we can confirm this is the case by running the following command
kubectl -n ${NAMESPACE} get pods -l service=envoy

NAME                     READY     STATUS    RESTARTS   AGE
envoy-76774f8d5c-lx9bd   2/2       Running   2          4m
envoy-76774f8d5c-ngjnr   2/2       Running   2          4m
envoy-76774f8d5c-sg555   2/2       Running   2          4m

  • Try other services to see if they’re accessible for example

    https://${KUBEFLOW_FQDN}/whoami
https://${KUBEFLOW_FQDN}/tfjobs/ui
https://${KUBEFLOW_FQDN}/hub

  • If other services are accessible then we know its a problem specific to the central dashboard and not ingress

  • Check that the centraldashboard is running

    kubectl get pods -l app=centraldashboard
NAME                                READY     STATUS    RESTARTS   AGE
centraldashboard-6665fc46cb-592br   1/1       Running   0          7h

  • Check a service for the central dashboard exists

    kubectl get service -o yaml centraldashboard

  • Check that an Ambassador route is properly defined

    kubectl get service centraldashboard -o jsonpath='{.metadata.annotations.getambassador\.io/config}'

apiVersion: ambassador/v0
  kind:  Mapping
  name: centralui-mapping
  prefix: /
  rewrite: /
  service: centraldashboard.kubeflow,

  • Check the logs of Ambassador for errors. See if there are errors like the following indicating an error parsing the route.If you are using the new Stackdriver Kubernetes monitoring you can use the following filter in the stackdriver console

     resource.type="k8s_container"
 resource.labels.location=${ZONE}
 resource.labels.cluster_name=${CLUSTER}
 metadata.userLabels.service="ambassador"
"could not parse YAML"

502 Server Error

A 502 usually means traffic isn’t even making it to the envoy reverse proxy. And it usually indicates the loadbalancer doesn’t think any backends are healthy.

  • In Cloud Console select Network Services -> Load Balancing

    • Click on the load balancer (the name should contain the name of the ingress)

    • The exact name can be found by looking at the ingress.kubernetes.io/url-map annotation on your ingress object

      URLMAP=$(kubectl --namespace=${NAMESPACE} get ingress envoy-ingress -o jsonpath='{.metadata.annotations.ingress\.kubernetes\.io/url-map}')
echo ${URLMAP}

    • Click on your loadbalancer

    • This will show you the backend services associated with the load balancer

      • There is 1 backend service for each K8s service the ingress rule routes traffic too

      • The named port will correspond to the NodePort a service is using

        NODE_PORT=$(kubectl --namespace=${NAMESPACE} get svc envoy -o jsonpath='{.spec.ports[0].nodePort}')
BACKEND_NAME=$(gcloud compute --project=${PROJECT} backend-services list --filter=name~k8s-be-${NODE_PORT}- --format='value(name)')
gcloud compute --project=${PROJECT} backend-services get-health --global ${BACKEND_NAME}

    • Make sure the load balancer reports the backends as healthy

      • If the backends aren’t reported as healthy check that the pods associated with the K8s service are up and running

      • Check that health checks are properly configured

        • Click on the health check associated with the backend service for envoy
        • Check that the path is /healthz and corresponds to the path of the readiness probe on the envoy pods
        • See K8s docs for important information about how health checks are determined from readiness probes.

      • Check firewall rules to ensure traffic isn’t blocked from the GCP loadbalancer

        • The firewall rule should be added automatically by the ingress but its possible it got deleted if you have some automatic firewall policy enforcement. You can recreate the firewall rule if needed with a rule like this

          gcloud compute firewall-rules create $NAME \
--project $PROJECT \
--allow tcp:$PORT \
--target-tags $NODE_TAG \
--source-ranges 130.211.0.0/22,35.191.0.0/16

        • To get the node tag

          # From the Kubernetes Engine cluster get the name of the managed instance group
gcloud --project=$PROJECT container clusters --zone=$ZONE describe $CLUSTER
# Get the template associated with the MIG
gcloud --project=kubeflow-rl compute instance-groups managed describe --zone=${ZONE} ${MIG_NAME}
# Get the instance tags from the template
gcloud --project=kubeflow-rl compute instance-templates describe ${TEMPLATE_NAME}

          For more info see GCP HTTP health check docs

    • In Stackdriver Logging look at the Cloud Http Load Balancer logs

      • Logs are labeled with the forwarding rule
      • The forwarding rules are available via the annotations on the ingress 
        ingress.kubernetes.io/forwarding-rule
ingress.kubernetes.io/https-forwarding-rule

    • Verify that requests are being properly routed within the cluster

    • Connect to one of the envoy proxies

      ```
kubectl exec -ti `kubectl get pods --selector=service=envoy -o jsonpath='{.items[0].metadata.name}'` /bin/bash
```

    • Install curl in the pod

    apt-get update && apt-get install -y curl
    • Verify access to the whoami app
    curl -L -s -i http://envoy:8080/noiap/whoami
    • If this doesn’t return a 200 OK response; then there is a problem with the K8s resources
      • Check the pods are running
      • Check services are pointing at the points (look at the endpoints for the various services)

Envoy pods crash-looping: root cause is backend quota exceeded

If your logs show the Envoy pods crash-looping, the root cause may be that you have exceeded your quota for some backend services such as loadbalancers. This is particularly likely if you have multiple, differently named deployments in the same GCP project using Cloud IAP.

The error

The error looks like this for the pod’s Envoy container:

kubectl logs -n kubeflow envoy-79ff8d86b-z2snp envoy
[2019-01-22 00:19:44.400][1][info][main] external/envoy/source/server/server.cc:184] initializing epoch 0 (hot restart version=9.200.16384.127.options=capacity=16384, num_slots=8209 hash=228984379728933363)
[2019-01-22 00:19:44.400][1][critical][main] external/envoy/source/server/server.cc:71] error initializing configuration '/etc/envoy/envoy-config.json': unable to read file: /etc/envoy/envoy-config.json

And the Cloud IAP container shows a message like this:

Waiting for backend id PROJECT=<your-project> NAMESPACE=kubeflow SERVICE=envoy filter=name~k8s-be-30352-...

Diagnosing the cause

You can verify the cause of the problem by entering the following command:

kubectl -n kubeflow describe ingress

Look for something like this in the output:

Events:
  Type     Reason  Age                  From                     Message
  ----     ------  ----                 ----                     -------
  Warning  Sync    14m (x193 over 19h)  loadbalancer-controller  Error during sync: googleapi: Error 403: Quota 'BACKEND_SERVICES' exceeded. Limit: 5.0 globally., quotaExceeded

Fixing the problem

Note: You can ignore the error you have not enabled Cloud IAP for the cluster, that is, if you are connecting via a port-forward.

If you have any redundant Kubeflow deployments, you can delete them using the Deployment Manager.

Alternatively, you can request more backend services quota on the GCP Console.

  1. Go to the quota settings for backend services on the GCP Console.
  2. Click EDIT QUOTAS. A quota editing form opens on the right of the screen.
  3. Follow the form instructions to apply for more quota.

Legacy networks are not supported

Cloud Filestore and GKE try to use the network named default by default. For older projects, this will be a legacy network which is incompatible with Cloud Filestore and newer GKE features like private clusters. This will manifest as the error “default is invalid; legacy networks are not supported” when deploying Kubeflow.

Here’s an example error when deploying Cloud Filestore:

ERROR: (gcloud.deployment-manager.deployments.update) Error in Operation [operation-1533189457517-5726d7cfd19c9-e1b0b0b5-58ca11b8]: errors:
- code: RESOURCE_ERROR
  location: /deployments/jl-0801-b-gcfs/resources/filestore
  message: '{"ResourceType":"gcp-types/file-v1beta1:projects.locations.instances","ResourceErrorCode":"400","ResourceErrorMessage":{"code":400,"message":"network
    default is invalid; legacy networks are not supported.","status":"INVALID_ARGUMENT","statusMessage":"Bad
    Request","requestPath":"https://file.googleapis.com/v1beta1/projects/cloud-ml-dev/locations/us-central1-a/instances","httpMethod":"POST"}}'

To fix this we can create a new network:

cd ${KFAPP}
cp .cache/master/deployment/gke/deployment_manager_configs/network.* \
   ./gcp_config/

Edit network.yaml to set the name for the network.

Edit gcfs.yaml to use the name of the newly created network.

Apply the changes.

cd ${KFAPP}
kfctl apply platform

CPU platform unavailable in requested zone

By default we set minCpuPlatform to Intel Haswell to make sure AVX2 is supported. See troubleshooting for more details.

If you encounter this CPU platform unavailable error (might manifest as Cluster is currently being created, deleted, updated or repaired and cannot be updated.), you can change the zone or change the minCpuPlatform. See here for available zones and cpu platforms.

Changing the OAuth client used by IAP

If you need to change the OAuth client used by IAP you can run the following commands to replace the K8s secret containing the id and secret.

kubectl -n kubeflow delete secret kubeflow-oauth
kubectl -n kubeflow create secret generic kubeflow-oauth \
       --from-literal=CLIENT_ID=${CLIENT_ID} \
       --from-literal=CLIENT_SECRET=${CLIENT_SECRET}
Last modified 28.04.2019: Resolved typos (#665) (44f20b50)