### Install Control plane

This can run in any cluster. A mesh should have at least one cluster should run Pilot or equivalent XDS server,
and it is recommended to have Pilot running in each region and in multiple availability zones for multi cluster.

```bash
iop istio-control istio-discovery $IBASE/istio-control/istio-discovery \
            --set global.istioNamespace=istio-system

# Second istio-discovery, using master version of istio

  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ListMeta metadata = 1;

  // items is the list of endpoint slices
  repeated EndpointSlice items = 2;
}

// ForZone provides information about which zones should consume this endpoint.
message ForZone {
  // name represents the name of the zone.
  optional string name = 1;

  // More information can be found in https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/#time-zones
  // +optional
  optional string timeZone = 8;

  // Optional deadline in seconds for starting the job if it misses scheduled
  // time for any reason.  Missed jobs executions will be counted as failed ones.
  // +optional
  optional int64 startingDeadlineSeconds = 2;

  // 	  :443 for https.
  // Both these may change in the future.
  // Incoming requests are matched against the host before the
  // IngressRuleValue. If the host is unspecified, the Ingress routes all
  // traffic based on the specified IngressRuleValue.
  //
  // host can be "precise" which is a domain name without the terminating dot of
  // a network host (e.g. "foo.bar.com") or "wildcard", which is a domain name

  // 	  :443 for https.
  // Both these may change in the future.
  // Incoming requests are matched against the host before the
  // IngressRuleValue. If the host is unspecified, the Ingress routes all
  // traffic based on the specified IngressRuleValue.
  //
  // host can be "precise" which is a domain name without the terminating dot of
  // a network host (e.g. "foo.bar.com") or "wildcard", which is a domain name

  // than a virtual IP.
  // "NodePort" builds on ClusterIP and allocates a port on every node which
  // routes to the same endpoints as the clusterIP.
  // "LoadBalancer" builds on NodePort and creates an external load-balancer
  // (if supported in the current cloud) which routes to the same endpoints
  // as the clusterIP.
  // "ExternalName" aliases this service to the specified externalName.

turns the above inputs into the actual types consumed by the connected XDS clients (typically Envoy). This is done by `Generators`, which register a function to build a given type. For example, there is a `RouteGenerator` responsible for building `Routes`. Along with the core Envoy XDS types, there are a few custom Istio types, such as our `NameTable` type used for DNS, as well as debug interfaces.

`Generators` get as input the `Proxy` (a representation of the current client), the current...

  // selected by this will be the ones affected by this deployment.
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 2;

  // Template describes the pods that will be created.
  optional k8s.io.api.core.v1.PodTemplateSpec template = 3;

  // The deployment strategy to use to replace existing pods with new ones.
  // +optional
  // +patchStrategy=retainKeys

  // `/foo` would allow `/foo`, `/foo/` and `/foo/bar`
  // `/foo` would not allow `/food` or `/etc/foo`
  optional string pathPrefix = 1;

  // when set to true, will allow host volumes matching the pathPrefix only if all volume mounts are readOnly.
  // +optional
  optional bool readOnly = 2;
}

// Eviction evicts a pod from its node subject to certain policies and safety constraints.