- the actual code is in pkg/install - including a readiness probe, monitoring.
    - it also sets up a UDS socket for istio-cni to send logs to this container.
    - based on config, it may run the 'repair' controller that detects pods where istio setup fails and restarts them, or created in corner cases.

Istio installer is a modular, 'a-la-carte' installer for Istio. It is based on a
fork of the Istio helm templates, refactored to increase modularity and isolation.

Goals:
- Improve upgrade experience: users should be able to gradually roll upgrades, with proper
canary deployments for Istio components. It should be possible to deploy a new version while keeping the

the spec.

## Interaction with controller

The controller shares the same API as the operator CLI, so it's possible to install any of the above examples as a CR
in the cluster in the istio-system namespace and the controller will react to it with the same outcome as running
`istioctl install -f <path-to-custom-resource-file>`.

## Architecture

### GKE notes

On GKE, 'kube-system' is required.

If using `helm template`, `--set cni.cniBinDir=/home/kubernetes/bin` is required - with `helm install`

   functions.

  > Note: The service mesh is not an overlay network. It
  > simplifies and enhances how microservices in an application talk to each
  > other over the network provided by the underlying platform.

- **Istiod** - The Istio control plane. It provides service discovery, configuration and certificate management. It consists of the following sub-components:

#### Legacy Gateway Helm charts

Istio historically offered two different charts - `manifests/charts/gateways/istio-ingress` and `manifests/charts/gateways/istio-egress`.
These are replaced by this chart.
While not required, it is recommended all new users use this chart, and existing users migrate when possible.

This chart has the following benefits and differences: