// RFC-6335 and https://www.iana.org/assignments/service-names).
  //
  // * Kubernetes-defined prefixed names:
  //   * 'kubernetes.io/h2c' - HTTP/2 over cleartext as described in https://www.rfc-editor.org/rfc/rfc7540
  //
  // * Other protocols should use implementation-defined prefixed names such as
  // mycompany.com/my-custom-protocol.
  // +optional
  optional string appProtocol = 4;

  // +patchMergeKey=name
  // +patchStrategy=merge
  repeated CSINodeDriver drivers = 1;
}

// CSIStorageCapacity stores the result of one CSI GetCapacity call.
// For a given StorageClass, this describes the available capacity in a
// particular topology segment.  This can be used when considering where to
// instantiate new PersistentVolumes.
//
// For example this can express things like:

  //   must be a BER-encoded ASN.1 Certificate structure as described in section 4 of RFC5280.
  //  3. Non-PEM content may appear before or after the "CERTIFICATE" PEM blocks and is unvalidated,
  //   to allow for explanatory text as described in section 5.2 of RFC7468.
  //
  // If more than one PEM block is present, and the definition of the requested spec.signerName

  // Read-only.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
  // +optional
  optional DaemonSetStatus status = 3;
}

// DaemonSetCondition describes the state of a DaemonSet at a certain point.
message DaemonSetCondition {
  // Type of DaemonSet condition.
  optional string type = 1;

  // Status of the condition, one of True, False, Unknown.

  optional string subresource = 1;

  // responseKind describes the group, version, and kind of the serialization schema for the object type this endpoint typically returns.
  // Some subresources do not return normal resources, these will have null return types.
  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionKind responseKind = 2;

  // acceptedTypes describes the kinds that this endpoint accepts.

  // +optional
  optional ListMeta metadata = 1;

  // List of objects
  repeated k8s.io.apimachinery.pkg.runtime.RawExtension items = 2;
}

// ListMeta describes metadata that synthetic resources must have, including lists and
// various status objects. A resource may have only one of {ObjectMeta, ListMeta}.
message ListMeta {

# Architecture of Istiod

This document describes the high level architecture of the Istio control plane, Istiod.
Istiod is structured as a modular monolith, housing a wide range of functionality from certificate signing, proxy configuration (XDS), traditional Kubernetes controllers, and more.

## Proxy Configuration

# Istio Agent

This document describes the internal architecture of Istio agent.

## High Level overview

![High Level overview](docs/overview.svg)

At a high level, the Istio agent acts as an intermediate proxy between Istiod and Envoy. This is done
at two levels. For distributing workload certificates, Envoy will send [SDS](https://www.envoyproxy.io/docs/envoy/latest/configuration/security/secret)

  // +optional
  optional HorizontalPodAutoscalerStatus status = 3;
}

// HorizontalPodAutoscalerCondition describes the state of
// a HorizontalPodAutoscaler at a certain point.
message HorizontalPodAutoscalerCondition {
  // type describes the current condition
  optional string type = 1;

  // status is the status of the condition (True, False, Unknown)
  optional string status = 2;

  // +optional
  optional DeploymentSpec spec = 2;

  // Most recently observed status of the Deployment.
  // +optional
  optional DeploymentStatus status = 3;
}

// DeploymentCondition describes the state of a deployment at a certain point.
message DeploymentCondition {
  // Type of deployment condition.
  optional string type = 1;

  // Status of the condition, one of True, False, Unknown.