* Ensure traffic between mesh workloads is securely encrypted with an Istio identity.
* Be lightweight enough to not limit adoption.
  * This puts a much tighter budget on CPU, memory, latency, and throughput requirements than traditional Istio sidecars.

Ztunnel was not designed to be a feature-rich data plane.
Quite the opposite - an *aggressively* small feature set is the key feature that makes ztunnel viable.

IstioOperator CR.
1. The controller has additional logic that mirrors istioctl commands like upgrade, but is driven from the declarative
API rather than command line.

### Quick tour of CLI commands

#### Flags

The `istioctl` command supports the following flags:

- `dry-run`: console output only, nothing applied to cluster or written to files.

  //
  // BorrowingCL(i) = round( NominalCL(i) * borrowingLimitPercent(i)/100.0 )
  //
  // The value of this field can be more than 100, implying that this
  // priority level can borrow a number of seats that is greater than
  // its own nominal concurrency limit (NominalCL).
  // When this field is left `nil`, the limit is effectively infinite.
  // +optional

  //
  // BorrowingCL(i) = round( NominalCL(i) * borrowingLimitPercent(i)/100.0 )
  //
  // The value of this field can be more than 100, implying that this
  // priority level can borrow a number of seats that is greater than
  // its own nominal concurrency limit (NominalCL).
  // When this field is left `nil`, the limit is effectively infinite.
  // +optional

  // Specifies the maximum desired number of pods the job should
  // run at any given time. The actual number of pods running in steady state will
  // be less than this number when ((.spec.completions - .status.successful) < .spec.parallelism),
  // i.e. when the work left to do is less than max parallelism.
  // More info: https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/
  // +optional
  optional int32 parallelism = 1;

  // same controller. For example, you may have different parameters for the
  // same implementing controller. This should be specified as a
  // domain-prefixed path no more than 250 characters in length, e.g.
  // "acme.io/ingress-controller". This field is immutable.
  optional string controller = 1;

  // parameters is a link to a custom resource containing additional

  // reinvocationPolicy indicates whether this webhook should be called multiple times as part of a single admission evaluation.
  // Allowed values are "Never" and "IfNeeded".
  //
  // Never: the webhook will not be called more than once in a single admission evaluation.
  //
  // IfNeeded: the webhook will be called at least one additional time as part of the admission evaluation

  // everywhere.
  // +optional
  optional k8s.io.api.core.v1.NodeSelector availableOnNodes = 2;

  // Shareable determines whether the resource supports more
  // than one consumer at a time.
  // +optional
  optional bool shareable = 3;
}

// PodSchedulingContext objects hold information that is needed to schedule
// a Pod with ResourceClaims that use "WaitForFirstConsumer" allocation

  // same controller. For example, you may have different parameters for the
  // same implementing controller. This should be specified as a
  // domain-prefixed path no more than 250 characters in length, e.g.
  // "acme.io/ingress-controller". This field is immutable.
  optional string controller = 1;

  // parameters is a link to a custom resource containing additional

  // reinvocationPolicy indicates whether this webhook should be called multiple times as part of a single admission evaluation.
  // Allowed values are "Never" and "IfNeeded".
  //
  // Never: the webhook will not be called more than once in a single admission evaluation.
  //
  // IfNeeded: the webhook will be called at least one additional time as part of the admission evaluation