Version 1.4. This version is no longer supported. For more information see the version support policy.

Troubleshooting

The following sections describe issues you might encounter while using GKE on-prem, and how to resolve them.

Before you begin

Check the following sections before you begin troubleshooting an issue.

Diagnosing cluster issues using `gkectl`

Use gkectl diagnosecommands to identify cluster issues and share cluster information with Google. See Diagnosing cluster issues.

Running `gkectl` commands verbosely

-v5

Logging `gkectl` errors to `stderr`

--alsologtostderr

Locating `gkectl` logs in the admin workstation

Even if you don't pass in its debugging flags, you can view gkectl logs in the following admin workstation directory:

/home/ubuntu/.config/gke-on-prem/logs

Locating Cluster API logs in the admin cluster

If a VM fails to start after the admin control plane has started, you can try debugging this by inspecting the Cluster API controllers' logs in the admin cluster:

Find the name of the Cluster API controllers Pod in the kube-system namespace, where [ADMIN_CLUSTER_KUBECONFIG] is the path to the admin cluster's kubeconfig file:
```
kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] -n kube-system get pods | grep clusterapi-controllers
```
Open the Pod's logs, where [POD_NAME] is the name of the Pod. Optionally, use grep or a similar tool to search for errors:
```
kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] -n kube-system logs [POD_NAME] vsphere-controller-manager
```

Installation

Debugging F5 BIG-IP issues using the admin cluster control plane node's kubeconfig

After an installation, GKE on-prem generates a kubeconfig file in the home directory of your admin workstation named internal-cluster-kubeconfig-debug. This kubeconfig file is identical to your admin cluster's kubeconfig, except that it points directly at the admin cluster's control plane node, where the admin control plane runs. You can use the internal-cluster-kubeconfig-debug file to debug F5 BIG-IP issues.

`gkectl check-config` validation fails: can't find F5 BIG-IP partitions

Symptoms: Validation fails because F5 BIG-IP partitions can't be found, even though they exist.
Potential causes: An issue with the F5 BIG-IP API can cause validation to fail.
Resolution: Try running gkectl check-config again.

`gkectl prepare --validate-attestations` fails: could not validate build attestation

Symptoms

Running gkectl prepare with the optional --validate-attestations flag returns the following error:

could not validate build attestation for gcr.io/gke-on-prem-release/.../...: VIOLATES_POLICY

Potential causes

An attestation might not exist for the affected image(s).

Resolution

Try downloading and deploying the admin workstation OVA again, as instructed in Creating an admin workstation. If the issue persists, reach out to Google for assistance.

Debugging using the bootstrap cluster's logs

During installation, GKE on-prem creates a temporary bootstrap cluster. After a successful installation, GKE on-prem deletes the bootstrap cluster, leaving you with your admin cluster and user cluster. Generally, you should have no reason to interact with this cluster.

If something goes wrong during an installation, and you did pass --cleanup-external-cluster=false to gkectl create cluster, you might find it useful to debug using the bootstrap cluster's logs. You can find the Pod, and then get its logs:

kubectl --kubeconfig /home/ubuntu/.kube/kind-config-gkectl get pods -n kube-system

kubectl --kubeconfig /home/ubuntu/.kube/kind-config-gkectl -n kube-system get logs [POD_NAME]

Authentication plugin for GKE Enterprise

Failure running `gkectl create-login-config`

Issue 1:

Symptoms

When running gkectl create-login-config, you encounter the following error:

Error getting clientconfig using [user_cluster_kubeconfig]

Potential causes

This error means either the kubeconfig file passed to gkectl create-login-config is not for a user cluster or the ClientConfig CRD did not come up during cluster creation.

Resolution

Run the following command to see if the ClientConfig CRD is in the cluster:

$ kubectl --kubeconfig
  [user_cluster_kubeconfig] get clientconfig default -n kube-public

Issue 2:

Symptoms

When running gkectl create-login-config, you encounter the following error:

error merging with file [merge_file] because [merge_file] contains a
  cluster with the same name as the one read from [kubeconfig]. Please write to
  a new output file

Potential causes

Each login configuration file must contain unique cluster names. If you are seeing this error, the file you are writing login config data to contains a cluster name that already exists in the destination file.

Resolution

Write to a new --output file. Note the following:

If --output is not provided, the login config data will be written to a file called kubectl-anthos-config.yaml in the current directory by default.
If --output already exists, the command will try to merge the new login config to --output.

Failure running `gcloud anthos auth login`

Issue 1:

Symptoms: Running login using the auth plugin and the generated login config YAML file fails.
Potential causes: There might be an error in the OIDC configuration details.
Resolution: Verify OIDC client registration with your administrator.

Issue 2:

Symptoms: When a proxy is configured for HTTPS traffic, running the gcloud anthos auth login command fails with proxyconnect tcp in the error message. An example of the type of message you might see is proxyconnect tcp: tls: first record does not look like a TLS handshake.
Potential causes: There might be an error in the https_proxy or HTTPS_PROXY environment variable configurations. If there's an https:// specified in the environment variables, then the GoLang HTTP client libraries might fail if the proxy is configured to handle HTTPS connections using other protocols such as SOCK5.
Resolution: Modify the https_proxy and HTTPS_PROXY environment variables to omit the https:// prefix. On Windows, modify the system environment variables. For example, change the value of the https_proxy environment variable from https://webproxy.example.com:8000 to webproxy.example.com:8000.

Failure using kubeconfig generated by `gcloud anthos auth login` to access cluster

Symptoms

"Unauthorized" Error

If there is an `Unauthorized` error when using the kubeconfig generated by gcloud anthos auth login to access the cluster, this means that the apiserver is unable to authorize the user.

Potential causes

Either the appropriate RBACs are missing or incorrect or there is an error in the OIDC configuration for the cluster.

Resolution

Try the following steps to resolve the issue:

Parse the id-token from kubeconfig.

In the kubeconfig file that was generated by the login command, copy the id-token:
```
kind: Config
…
users:
- name: …
  user:
    auth-provider:
      config:
        id-token: [id-token]
        …
```
Follow the steps to install jwt-cli and run:
```
$ jwt [id-token]
```
Verify OIDC configuration

The oidc section filled out in config.yaml, which was used to create the cluster, contains the fields group and username, which are used to set the flags --oidc-group-claim and --oidc-username-claim in the apiserver. When the apiserver is presented with the token, it will look for that group- claim and username-claim and verify that the corresponding group or user has the correct permissions.

Verify that the claims set for group and user in the oidc section of config.yaml are present in the id-token.
Check RBACs that were applied.

Verify that there is an RBAC with the correct permissions for either the user specified by the username-claim or one of the groups listed under the group-claim from the previous step. The name of the user or group in the RBAC should be prefixed with the usernameprefix or groupprefix that was provided in the oidc section of config.yaml.

Note that if usernameprefix was left blank, and username is a value other than email, the prefix will default to issuerurl#. To disable username prefixes, usernameprefix should be set to -.

For more information about user and group prefixes, see Populating the oidc spec.

Note that the Kubernetes API server currently treats a backslash as an escape character. Therefore, if the name of the user or group contains \\, the API server will read it as a single \ when parsing the id_token. Therefore, the RBAC applied for this user or group should only contain a single backslash, or you might see an Unauthorized error.

Example:

config.yaml:
```
oidc:
    issuerurl:
    …
    username: "unique_name"
    usernameprefix: "-"
    group: "group"
    groupprefix: "oidc:"
    ...
```
id_token:
```
{
  ...
  "email": "cluster-developer@example.com",
  "unique_name": "EXAMPLE\\cluster-developer",
  "group": [
    "Domain Users",
    "EXAMPLE\\developers"
],
  ...
}
```
The following RBACs would grant this user cluster-admin permissions (note the single slash in the name field instead of a double slash):

Group RBAC:
```
apiVersion:
kind:
metadata:
   name: example-binding
subjects:
-  kind: Group
   name: "oidc:EXAMPLE\developers"
   apiGroup: rbac.authorization.k8s.io
   roleRef:
     kind: ClusterRole
     name: pod-reader
     apiGroup: rbac.authorization.k8s.io
```
User RBAC:
```
apiVersion:
kind:
metadata:
   name: example-binding
subjects:
-  kind: User
               name: "EXAMPLE\cluster-developer"
               apiGroup: rbac.authorization.k8s.io
           roleRef:
           kind: ClusterRole
               name: pod-reader
               apiGroup: rbac.authorization.k8s.io
```
Check API Server logs

If the OIDC plugin configured in the kube apiserver does not start up correctly, the API server will return an "Unauthorized" error when presented with the id-token. To see if there were any issues with the OIDC plugin in the API server, run:
```
$ kubectl
      --kubeconfig=[admin_cluster_kubeconfig] logs statefulset/kube-apiserver -n
      [user_cluster_name]
```

Symptoms

Unable to connect to the server: Get {DISCOVERY_ENDPOINT}: x509: certificate signed by unknown authority

Potential causes

The refresh token in the kubeconfig expired.

Resolution

Run the login command again.

The following are common errors that might occur while using Google Cloud console to try to log in:

Login redirects to page with "URL not found" error

Symptoms

Google Cloud console is not able to reach the GKE on-prem identity provider.

Potential causes

Google Cloud console is not able to reach the GKE on-prem identity provider.

Resolution

Try the following steps to resolve the issue:

Set useHTTPProxy to true

If the IDP is not reachable over the public internet, then you will need to enable the OIDC HTTP Proxy to login via Google Cloud console. In the oidc section of config.yaml, usehttpproxy should be set to true. If you have already created a cluster and want to turn on the proxy, you can edit the ClientConfig CRD directly. Run $ kubectl edit clientconfig default -n kube-public and change useHTTPProxy to true.
useHTTPProxy is already set to true

If the HTTP proxy is enabled and you are still seeing this error,there might have been an issue with the proxy starting up. To get the logs of the proxy, run $ kubectl logs deployment/clientconfig-operator -n kube-system. Note that even if your IDP has a well known CA, for the http proxy to start, the field capath in the oidc section of config.yaml must be provided.
IDP prompts for consent

If the authorization server prompts for consent, and you have not included the extraparam prompt=consent, then you might see this error. Run $ kubectl edit clientconfig default -n kube-public and add prompt=consent to extraparams and try logging in again.
RBACs are misconfigured

If you have not done so already, try authenticating using the Authentication Plugin for Anthos. If you are seeing an authorization error logging in with the plugin as well, then follow the troubleshooting steps to resolve the issue with the plugin, and then try logging in via Google Cloud console again.
Try logging out and logging back in

In some cases, if some settings are changed on storage service, you might need to log out explicitly. Go to the cluster details page, click Log out, and try logging back in.

Admin workstation

`AccessDeniedException` while downloading OVA

Symptoms

Attempting to download the admin workstation OVA and signature returns the following error:

AccessDeniedException: 403 whitelisted-service-account@project.iam.gserviceaccount.com does not have storage.objects.list access to gke-on-prem-release

Potential causes

Your allowlisted service account is not activated.

Resolution

Make sure you have activated your allowlisted service account. If the issue persists, reach out to Google for assistance.

`openssl` can't validate admin workstation OVA

Symptoms: Running openssl dgst against the admin workstation OVA file doesn't return Verified OK
Potential causes: An issue is present in the OVA file that prevents successful validation.
Resolution: Try downloading and deploying the admin workstation OVA again, as instructed in Download the admin workstation OVA . If the issue persists, reach out to Google for assistance.

Connect

Unable to register a user cluster

If you encounter issues with registering user clusters, reach out to Google for assistance.

Cluster created during alpha was deregistered

Refer to Registering a user cluster in the Connect documentation.

You might also choose to delete and recreate the cluster.

Storage

Volume fails to attach

Symptoms

The output of gkectl diagnose cluster looks like the following:

Checking cluster object...PASS
Checking machine objects...PASS
Checking control plane pods...PASS
Checking gke-connect pods...PASS
Checking kube-system pods...PASS
Checking gke-system pods...PASS
Checking storage...FAIL
    PersistentVolume pvc-776459c3-d350-11e9-9db8-e297f465bc84: virtual disk "[datastore_nfs] kubevols/kubernetes-dynamic-pvc-776459c3-d350-11e9-9db8-e297f465bc84.vmdk" IS attached to machine "gsl-test-user-9b46dbf9b-9wdj7" but IS NOT listed in the Node.Status
1 storage errors

One or more Pods is stuck in ContainerCreating state with a warning like the following:

Events:
  Type     Reason              Age               From                     Message
  ----     ------              ----              ----                     -------
  Warning  FailedAttachVolume  6s (x6 over 31s)  attachdetach-controller  AttachVolume.Attach failed for volume "pvc-776459c3-d350-11e9-9db8-e297f465bc84" : Failed to add disk 'scsi0:6'.

Potential causes

If a virtual disk is attached to the wrong virtual machine, it may be due to issue #32727 in Kubernetes 1.12.

Resolution

If a virtual disk is attached to the wrong virtual machine, you might need to manually detach it:

Drain the node. See Safely draining a node. You might want to include the --ignore-daemonsets and --delete-local-data flags in your kubectl drain command.
Power off the VM.
Edit the VM's hardware config in vCenter to remove the volume.
Power on the VM
Uncordon the node.

Volume is lost

Symptoms

The output of gkectl diagnose cluster looks like the following:

Checking cluster object...PASS
Checking machine objects...PASS
Checking control plane pods...PASS
Checking gke-connect pods...PASS
Checking kube-system pods...PASS
Checking gke-system pods...PASS
Checking storage...FAIL
    PersistentVolume pvc-52161704-d350-11e9-9db8-e297f465bc84: virtual disk "[datastore_nfs] kubevols/kubernetes-dynamic-pvc-52161704-d350-11e9-9db8-e297f465bc84.vmdk" IS NOT found
1 storage errors

One or more Pods is stuck in ContainerCreating state with a warning like the following:

Events:
  Type     Reason              Age                   From                                    Message
  ----     ------              ----                  ----                                    -------
  Warning  FailedAttachVolume  71s (x28 over 42m)    attachdetach-controller                 AttachVolume.Attach failed for volume "pvc-52161704-d350-11e9-9db8-e297f465bc84" : File []/vmfs/volumes/43416d29-03095e58/kubevols/
  kubernetes-dynamic-pvc-52161704-d350-11e9-9db8-e297f465bc84.vmdk was not found

Potential causes

If you see a "not found" error related to your VMDK file, it is likely that the virtual disk was permanently deleted. This can happen if an operator manually deletes a virtual disk or the virtual machine it is attached to. To prevent this, manage your virtual machines as described in Resizing a user cluster and Upgrading clusters

Resolution

If a virtual disk was permanently deleted, you might need to manually clean up related Kubernetes resources:

Delete the PVC that referenced the PV by running kubectl delete pvc [PVC_NAME].
Delete the Pod that referenced the PVC by running kubectl delete pod [POD_NAME].
Repeat step 2. (Yes, really. See Kubernetes issue 74374.)

Upgrades

About downtime during upgrades

Resource	Description
Admin cluster	When an admin cluster is down, user cluster control planes and workloads on user clusters continue to run, unless they were affected by a failure that caused the downtime
User cluster control plane	Typically, you should expect no noticeable downtime to user cluster control planes. However, long-running connections to the Kubernetes API server might break and would need to be re-established. In those cases, the API caller should retry until it establishes a connection. In the worst case, there can be up to one minute of downtime during an upgrade. Note: If user cluster nodes are unable reach the user control plane during the upgrade, new workloads are not scheduled to the cluster. Existing workloads are unaffected.
User cluster nodes	If an upgrade requires a change to user cluster nodes, GKE on-prem recreates the nodes in a rolling fashion, and reschedules Pods running on these nodes. You can prevent impact to your workloads by configuring appropriate PodDisruptionBudgets and anti-affinity rules.

Resizing user clusters

Resizing a user cluster fails

Symptoms

A resize operation on a user cluster fails.

Potential causes

Several factors could cause resize operations to fail.

Resolution

If a resize fails, follow these steps:

Check the cluster's MachineDeployment status to see if there are any events or error messages:
```
kubectl describe machinedeployments [MACHINE_DEPLOYMENT_NAME]
```
Check if there are errors on the newly-created Machines:
```
kubectl describe machine [MACHINE_NAME]
```

Error: "no addresses can be allocated"

Symptoms

After resizing a user cluster, kubectl describe machine [MACHINE_NAME] displays the following error:

Events:
   Type     Reason  Age                From                    Message
   ----     ------  ----               ----                    -------
   Warning  Failed  9s (x13 over 56s)  machineipam-controller  ipam: no addresses can be allocated

Potential causes

There aren't enough IP addresses available for the user cluster.

Resolution

Allocate more IP addresses for the cluster. Then, delete the affected Machine:

kubectl delete machine [MACHINE_NAME]

If the cluster is configured correctly, a replacement Machine is created with an IP address.

Sufficient number of IP addresses allocated, but Machine fails to register with cluster

Symptoms: Network has enough addresses allocated but the Machine still fails to register with the user cluster.
Possible causes: There might be an IP conflict. The IP might be taken by another Machine or by your load balancer.
Resolution: Check that the affected Machine's IP address is not taken. If there is a conflict, you need to resolve the conflict in your environment.

vSphere

Debugging with `govc`

If you encounter issues specific to vSphere, you can use govc to troubleshoot. For example, you can easily confirm permissions and access for your vCenter user accounts and collect vSphere logs.

Changing vCenter Certificate

If you are running a vCenter server in evaluation or default setup mode, and it has a generated TLS certificate, this certificate might change over time. If the certificate has changed, you need to let your running cluster(s) know about the new certificate:

Retrieve the new vCenter cert and save to a file:

true | openssl s_client -connect [VCENTER_IP_ADDRESS]:443 -showcerts 2>/dev/null | sed -ne '/-BEGIN/,/-END/p' > vcenter.pem

Now, for each cluster, delete the ConfigMap containing the vSphere and vCenter certificate for each cluster, and create a new ConfigMap with the new cert. For example:

kubectl --kubeconfig kubeconfig delete configmap vsphere-ca-certificate -n kube-system

kubectl --kubeconfig kubeconfig delete configmap vsphere-ca-certificate -n user-cluster1

kubectl --kubeconfig kubeconfig create configmap -n user-cluster1 --dry-run vsphere-ca-certificate --from-file=ca.crt=vcenter.pem  -o yaml  | kubectl --kubeconfig kubeconfig apply -f -

kubectl --kubeconfig kubeconfig create configmap -n kube-system --dry-run vsphere-ca-certificate --from-file=ca.crt=vcenter.pem  -o yaml  | kubectl --kubeconfig kubeconfig apply -f -

Delete the clusterapi-controllers Pod for each cluster. When the Pod restarts, it begins using the new certificate. For example:

kubectl --kubeconfig kubeconfig -n kube-system get pods

kubectl --kubeconfig kubeconfig -n kube-system delete pod clusterapi-controllers-...

Miscellaneous

Terraform vSphere provider session limit

GKE on-prem uses Terraform's vSphere provider to bring up VMs in your vSphere environment. The provider's session limit is 1000 sessions. The current implementation doesn't close active sessions after use. You might encounter 503 errors if you have too many sessions running.

Sessions are automatically closed after 300 seconds.

Symptoms

If you have too many sessions running, you might encounter the following error:

Error connecting to CIS REST endpoint: Login failed: body:
  {"type":"com.vmware.vapi.std.errors.service_unavailable","value":
  {"messages":[{"args":["1000","1000"],"default_message":"Sessions count is
  limited to 1000. Existing sessions are 1000.",
  "id":"com.vmware.vapi.endpoint.failedToLoginMaxSessionCountReached"}]}},
  status: 503 Service Unavailable

Potential causes

There are too many Terraform provider sessions running in your environment.

Resolution

Currently, this is working as intended. Sessions are automatically closed after 300 seconds. For more information, refer to to GitHub issue #618.

Using a proxy for Docker: `oauth2: cannot fetch token`

Symptoms

While using a proxy, you encounter the following error:

oauth2: cannot fetch token: Post https://oauth2.googleapis.com/token: proxyconnect tcp: tls: oversized record received with length 20527

Potential causes

You might have provided a HTTPS proxy instead of HTTP.

Resolution

In your Docker configuration, change the proxy address to http:// instead of https://.

Verifying that licenses are valid

Remember to verify that your licenses is valid, especially if you are using trial licenses. You might encounter unexpected failures if your F5, ESXi host, or vCenter licenses have expired.

Troubleshooting

Before you begin

Diagnosing cluster issues using gkectl

Running gkectl commands verbosely

Logging gkectl errors to stderr

Locating gkectl logs in the admin workstation

Locating Cluster API logs in the admin cluster

Installation

Debugging F5 BIG-IP issues using the admin cluster control plane node's kubeconfig

gkectl check-config validation fails: can't find F5 BIG-IP partitions

gkectl prepare --validate-attestations fails: could not validate build attestation

Debugging using the bootstrap cluster's logs

Authentication plugin for GKE Enterprise

Failure running gkectl create-login-config

Failure running gcloud anthos auth login

Failure using kubeconfig generated by gcloud anthos auth login to access cluster

Google Cloud console login

Login redirects to page with "URL not found" error

Admin workstation

AccessDeniedException while downloading OVA

openssl can't validate admin workstation OVA

Connect

Unable to register a user cluster

Cluster created during alpha was deregistered

Storage

Volume fails to attach

Symptoms

Potential causes

Resolution

Volume is lost

Symptoms

Potential causes

Resolution

Upgrades

About downtime during upgrades

Resizing user clusters

Resizing a user cluster fails

Error: "no addresses can be allocated"

Sufficient number of IP addresses allocated, but Machine fails to register with cluster

vSphere

Debugging with govc

Changing vCenter Certificate

Miscellaneous

Terraform vSphere provider session limit

Using a proxy for Docker: oauth2: cannot fetch token

Verifying that licenses are valid

Diagnosing cluster issues using `gkectl`

Running `gkectl` commands verbosely

Logging `gkectl` errors to `stderr`

Locating `gkectl` logs in the admin workstation

`gkectl check-config` validation fails: can't find F5 BIG-IP partitions

`gkectl prepare --validate-attestations` fails: could not validate build attestation

Failure running `gkectl create-login-config`

Failure running `gcloud anthos auth login`

Failure using kubeconfig generated by `gcloud anthos auth login` to access cluster

`AccessDeniedException` while downloading OVA

`openssl` can't validate admin workstation OVA

Debugging with `govc`

Using a proxy for Docker: `oauth2: cannot fetch token`