- [pod annotations](https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/)
- [container environment variables](https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/)
- [ImagePullPolicy](https://kubernetes.io/docs/concepts/containers/images/)

- sidecar interception is enabled if:
    - "istio-init" container is not present in the pod.
    - istio-proxy container exists and
        - does not have DISABLE_ENVOY environment variable (which triggers proxyless mode)
        - has a istio-proxy container, with first 2 args "proxy" and "sidecar" - or less then 2 args, or first arg not proxy.
        - "sidecar.istio.io/inject" is not false

### Install Istio-CNI

This is an optional step - CNI must run in a dedicated namespace, it is a 'singleton' and extremely
security sensitive. Access to the CNI namespace must be highly restricted.

**NOTE:** The environment variable `ISTIO_CLUSTER_ISGKE` is assumed to be set to `true` if the cluster
is a GKE cluster.

```bash
ISTIO_CNI_ARGS=
# TODO: What k8s data can we use for this check for whether GKE?