Installing OPA Gatekeeper
Managed Gatekeeper
TKE currently defaults to including managed OPA Gatekeeper, no need for self-installation.
Since gatekeeper is managed, the component itself is invisible in cluster, but related CRD resources can be seen:
kubectl get crd | grep gatekeeper.sh
Visual management available in cluster page's Policy Management page.
Self-built Gatekeeper
If complete control and policy customization desired, can consider opening whitelist via support ticket to avoid pre-installed gatekeeper, then create new cluster to self-install community version gatekeeper.
Since OPA Gatekeeper uses images on DockerHub, can directly use official YAML for one-click installation to TKE (TKE clusters have DockerHub image acceleration).
Refer to Official Installation Documentation: Deploying a Release using Prebuilt Image