Troubleshooting your on-premises connector setup

This page provides step by step instructions to help you troubleshoot your IAP On-premises Connector configuration. For additional troubleshooting information, see Traffic Director debugging.

Troubleshooting error 500 issues

Following are various issues and possible solutions to help you resolve a 500 error that you receive when attempting to access your application.

The on-premises application is not connected to the Google Cloud network

Your on-premises application might not be connected to the Google Cloud network. Verify connectivity by pinging the on-premises application from one of the on-premises connector Compute Engine instances. If the on-premises connector endpoint is unreachable, debug the network connectivity and settings before continuing.

Envoy is not properly installed in the VMs

Complete the following steps to verify that Envoy is properly installed:

  1. Log on to one of the Compute Engine VMs from the on-premises connector. The on-premises connector VM name starts with opc-on-prem-app-deployment-ig-${app}.
  2. In the Cloud console, verify that the opc-on-prem-app-deployment-gclb-urlmap load balancing backend service health checks are green.
  3. If the backend service does not show up as healthy, SSH into one of the instances:
     gcloud compute ssh instance-name --zone=zone name
  4. Verify that Envoy is up and running, by issuing the following command:

     ps aux | grep envoy
    There should be more than one process running, other than the grep envoy.

    An example output:

    envoy      943  0.0  0.0   5488  3076 ?        Ss   06:25   0:00 /bin/bash /usr/local/bin/
    envoy      944  0.1  1.5 178928 57352 ?        Sl   06:25   1:23 /usr/local/bin/envoy --config-path /usr/local/etc/
    envoy/envoy-proxy-bootstrap.json --allow-unknown-static-fields --disable-hot-restart --log-level info --drain-time-
    s 60
  5. Verify that the Envoy log directory is created at /var/log/envoy/.

  6. Ensure the gce-mesh bucket is reachable by the VMs, by issuing the following command:

    gsutil cp gs://gce-mesh/service-proxy-agent/releases/service-proxy-agent-0.2.tgz .

If any of the validations in this step failed, Envoy is not properly installed. Review the startup logs at /var/log/daemon.log for more information.

If you've observed that the Envoy isn't running from the earlier steps, one of the reasons could be VPC Service Controls. The start-up script in the VMs download the Envoy image from the gce-mesh bucket. If the VPC Service Controls rules don't allow the connection, the on-premises connector deployment will not work.

To ensure Envoy installs correctly, allow access to the gce-mesh storage bucket in VPC Service Controls in the host project. Also, ensure the VPC has a routing rule to allow traffic to the public internet. This allows Envoy to be deployed. For more information, see Ingress and egress rules.

Your on-premises application is not connected to Envoy

If you can ping the on-premises application from the VM but cannot use the on-premises connector, it's possible that Envoy cannot connect to the application.

To verify that Envoy can connect to your on-premises application, try making a call to Envoy from the machine where Envoy is running. SSH into the VM opc-on-prem-app-deployment-ig-${app} and run the following command. You can find the Envoy port number in Instance Groups > Details > Port Name Mapping.

shell curl -x -v localhost:${envoy_port}

If the endpoint is not reachable, check the following:

  • /var/log/envoy/envoy.err.log for any error logs. If there are no error logs, check if Traffic Director is enabled and is able to configure Envoy, by running the following command:
    sudo curl 
  • Verify that TRAFFICDIRECTOR_INTERCEPTION_LISTENER is set. If TRAFFICDIRECTOR_INTERCEPTION_LISTENER is not set, the Traffic Director could not configure Envoy.
  • Check for any error messages in each listener.

The Envoy and Traffic Director account permissions aren't set

If you see the GRPC 403 error in the envoy.err.log or if you do not see TRAFFICDIRECTOR_INTERCEPTION_LISTENER in the Envoy configuration, you might not have the correct account permissions set.

Verify that the VM service account has TD access permissions for xDS v3:

  • Verify the permissions:
  • Verify the account:


If the browser shows the error ERR_SSL_VERSION_OR_CIPHER_MISMATCH without redirecting to the login page, verify the status of the certificates on the Google Cloud load balancer details page.

Note that provisioning a Google-managed certificate might take up to 60 minutes.

Troubleshooting Envoy installation issue

If the on-premises connector is deployed successfully and the certificate has been provisioned, but the connection is still failing, this might indicate that Envoy might not be installed correctly on the VMs.

To verify if that Envoy is installed, SSH to one of the VMs and run the following command:

  •  ps aux | grep envoy 
    There should be more than one process running, other than the grep envoy.
  •  netstat -tlpn 
    The Envoy admin port should be listening.

If any of the previous actions fail, take the following actions to mitigate the issue:

  1. Make sure Private Google Access is enabled on the subnet the connector is being deployed.
  2. Make sure VM Manager (OS Config API) is enabled.

Troubleshooting Deployment Failure on IamMemberBinding Resources

If the on-premises connector is being deployed or updated and encounters a PERMISSION_DENIED error related to IamMemberBinding resources, it may be because the Google APIs Service Agent Service Account has not been granted the OWNER role as required when enabling IAP for on-premises apps.

Example Deployment Errors:

bind-iam-policy: {"ResourceType":"gcp-types/cloudresourcemanager-v1:virtual.projects.iamMemberBinding","ResourceErrorCode":"403","ResourceErrorMessage":{"code":403,"message":"Policy update access denied.","status":"PERMISSION_DENIED","statusMessage":"Forbidden","requestPath":"<project-ID>:setIamPolicy","httpMethod":"POST"}}
bind-storage-admin-account-iam-policy: {"ResourceType":"gcp-types/cloudresourcemanager-v1:virtual.projects.iamMemberBinding","ResourceErrorCode":"403","ResourceErrorMessage":{"code":403,"message":"Policy update access denied.","status":"PERMISSION_DENIED","statusMessage":"Forbidden","requestPath":"<project-ID>:setIamPolicy","httpMethod":"POST"}}

If you are seeing these errors with the deployment, verify the Google APIs Service Agent Service Account is granted the OWNER role and retry.