Uninstall the Istio add-on

These steps are specific to installations of the Istio on GKE, also referred to as the "Istio add-on".

Before you begin

• You must first review and ensure that you meet the requirements for upgrading.

• The commands on this page use the environment variables and migration script from the upgrade preparation step.

• It is important that you perform each step of this process in the specified order.

Identify if the Istio add-on is in use

There are two possible paths for migration depending on if either the ingress gateway or sidecar injection feature of the Istio add-on is in use within your cluster.

1. Earlier in the preparation step, you already identified if the Istio add-on is configured. You can run the following command to verify that the istio-system namespace exists:

   echo $INGRESS_NAMESPACE
   

2. Run the following command to determine if the sidecar injection feature of the Istio add-on is in use within your cluster:

   kubectl get ns -l istio-injection=enabled
   

   If any namespace, other than knative-serving is listed, it indicates that sidecar injection of the Istio add-on is in use.

   For example, if the command only lists the knative-serving namespace, then you have not configured and do not use sidecar injection of the Istio add-on.

Results:

• One or both used - One or both of the Istio add-on features are in use within your cluster:

  • Istio add-on ingress service istio-ingressgateway is used.
  • Istio add-on sidecar injection is used.

  Next steps: After you follow the instruction in the next section to uninstall the Istio add-on, you must proceed to the Cloud Service Mesh with the managed control plane guide.

• Not used - Neither the ingress gateway nor the sidecar injection of the Istio add-on are configure for use within your cluster. In other words, your installation uses the "bundled version of Istio".

  Next steps: After you follow the instruction in the next section to uninstall the unused Istio add-on, you can proceed to the Cloud Service Mesh with the in-cluster control plane guide.

Uninstall the Istio add-on

In this section, the migration script is used to uninstall the "Istio add-on".

1. Run the following command to start the migration script:

   ./migration-addon.sh --command uninstall-istio-addon
   

2. Verify that the istio-system namespace has been deleted:

   kubectl get ns istio-system --ignore-not-found
   

What's next

Depending on the ingress gateway configuration that you identified above, continue to the corresponding installation guide:

• If you identified earlier that one or both of the "Istio add-on" features were configured and used within your cluster, you must proceed to the Cloud Service Mesh with the managed control plane guide.

• If you identified earlier that neither the ingress gateway nor the sidecar injection of the "Istio add-on" were used in your cluster, then your installation actually used the "bundled version of Istio". You can now proceed to install Cloud Service Mesh with the in-cluster control plane.

Rollback

If you need to rollback the changes that you made through the steps above, you can use the migration script to re-enable the "Istio add-on":

1. Run the following command:

   ./migration-addon.sh --command rollback-uninstall-istio-addon
   

2. To continue rolling back your changes to your installation's original state, rollback the Knative serving "GKE add-on".