//   node label.
  // * topology.kubernetes.io/zone: the value indicates the zone where the
  //   endpoint is located. This should match the corresponding node label.
  // * topology.kubernetes.io/region: the value indicates the region where the
  //   endpoint is located. This should match the corresponding node label.
  // This field is deprecated and will be removed in future api versions.
  // +optional
  map<string, string> topology = 5;

### 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

  // topologyKeys is the list of keys supported by the driver.
  // When a driver is initialized on a cluster, it provides a set of topology
  // keys that it understands (e.g. "company.com/zone", "company.com/region").
  // When a driver is initialized on a node, it provides the same topology keys
  // along with values. Kubelet will expose these topology keys as labels
  // on its own node object.

  // topologyKeys is the list of keys supported by the driver.
  // When a driver is initialized on a cluster, it provides a set of topology
  // keys that it understands (e.g. "company.com/zone", "company.com/region").
  // When a driver is initialized on a node, it provides the same topology keys
  // along with values. Kubelet will expose these topology keys as labels
  // on its own node object.

  // +optional
  optional bool readOnly = 6;
}

// Represents a cinder volume resource in Openstack.
// A Cinder volume must exist before mounting to a container.
// The volume must also be in the same region as the kubelet.
// Cinder volumes support ownership management and SELinux relabeling.
message CinderPersistentVolumeSource {
  // volumeID used to identify the volume in cinder.