// Variable references $(VAR_NAME) are expanded using the container's environment. If a variable
  // cannot be resolved, the reference in the input string will be unchanged. Double $$ are reduced
  // to a single $, which allows for escaping the $(VAR_NAME) syntax: i.e. "$$(VAR_NAME)" will
  // produce the string literal "$(VAR_NAME)". Escaped references will never be expanded, regardless
  // of whether the variable exists or not. Cannot be updated.

  // podManagementPolicy controls how pods are created during initial scale up,
  // when replacing pods on nodes, or when scaling down. The default policy is
  // `OrderedReady`, where pods are created in increasing order (pod-0, then
  // pod-1, etc) and the controller will wait until each pod is ready before
  // continuing. When scaling down, the pods are removed in the opposite order.
  // The alternative policy is `Parallel` which will create pods in parallel

  podLabels:
    sidecar.istio.io/inject: "false"
  persistentVolume:
    enabled: false
  # Use port 9090 to match Istio documentation
  service:
    servicePort: 9090
  readinessProbeInitialDelay: 0
  # Speed up scraping a bit from the default
  global:
    scrape_interval: 15s

  # Match legacy addon deployment
  fullnameOverride: prometheus

  # use dockerhub
  image:
    repository: prom/prometheus

  optional string container = 4;
}

// ContainerResourceMetricStatus indicates the current value of a resource metric known to
// Kubernetes, as specified in requests and limits, describing a single container in each pod in the
// current scale target (e.g. CPU or memory).  Such metrics are built in to
// Kubernetes, and have special scaling options on top of those available to

control plane components.
- [Component configuration API](https://github.com/istio/api/blob/00671adacbea20f941cb20cce021bc63cbad1840/operator/v1alpha1/operator.proto#L42-L93), for managing
K8s settings like resources, auto scaling, pod disruption budgets and others defined in the
[KubernetesResourceSpec](https://github.com/istio/api/blob/00671adacbea20f941cb20cce021bc63cbad1840/operator/v1alpha1/operator.proto#L217-L271)
for Istio core and addon components.

  optional int32 periodSeconds = 3;
}

// HPAScalingRules configures the scaling behavior for one direction.
// These Rules are applied after calculating DesiredReplicas from metrics for the HPA.
// They can limit the scaling velocity by specifying scaling policies.
// They can prevent flapping by specifying the stabilization window, so that the

to apply to all top level resources annotations: {} # Additional volumeMounts to the ztunnel container volumeMounts: [] # Additional volumes to the ztunnel pod volumes: [] # Annotations added to each pod. The default annotations are required for scraping prometheus (in most environments). podAnnotations: prometheus.io/port: "15020" prometheus.io/scrape: "true" # Additional labels to apply on the pod level podLabels: {} # Pod resource configuration resources: requests: cpu: 500m memory: 2048Mi # List...

  // podManagementPolicy controls how pods are created during initial scale up,
  // when replacing pods on nodes, or when scaling down. The default policy is
  // `OrderedReady`, where pods are created in increasing order (pod-0, then
  // pod-1, etc) and the controller will wait until each pod is ready before
  // continuing. When scaling down, the pods are removed in the opposite order.
  // The alternative policy is `Parallel` which will create pods in parallel

Next, for an individual proxy we will check if it could possibly be impacted by the change. For example, we know a sidecar never is impacted by a `Gateway` update, and we can also look at scoping (from `Sidecar.egress.hosts`) to further restrict update scopes.

  // Example: when this is set to 30%, the old RC can be scaled down to 70% of desired pods
  // immediately when the rolling update starts. Once new pods are ready, old RC
  // can be scaled down further, followed by scaling up the new RC, ensuring
  // that the total number of pods available at all times during the update is at
  // least 70% of desired pods.
  // +optional