Istio is an open platform to connect, secure, control, and monitor microservices, reducing the complexity of managing microservice deployments. This documentation shows you how to quickly get started with Istio on Google Cloud.
Anthos customers can also use Anthos Service Mesh, a suite of tools to help you monitor and manage a reliable service mesh, powered by Istio. It includes a fully supported distribution of Istio along with managed components to make adoption of service mesh even easier.
You can try also Google Cloud's own Istio on GKE add-on for new or existing clusters, which makes sure you're using a GKE-tested version of Istio (installed automatically, and upgraded when you upgrade GKE). It has a default configuration that is known to work well on GKE.
If you need more configurability or want to control when you upgrade, refer to Getting Started in the Istio documentation.
There's lots more information about Istio in our overview and the Istio site.