#### CRD Watcher

For watches against custom types (CRDs), we want to gracefully handle missing CRDs. Naively starting informers against the missing types would result in errors and blocking startup. Instead, we introduce a "CRD Watcher" component that watches the CRDs in the cluster to determine if they are available or not.

- watches k8s resource for existing pods, so that pods that have already been started can be moved in or out of the ambient mesh.
- sends UDS events to ztunnel via a socket whenever a pod is enabled for ambient mesh (whether from CNI plugin or node watcher), instructing ztunnel to create the "tube" socket.

  // matches only a single label. You cannot have a wildcard label by itself (e.g. Host == "*").
  // Requests will be matched against the Host field in the following way:
  // 1. If host is precise, the request matches this rule if the http host header is equal to Host.
  // 2. If host is a wildcard, then the request matches this rule if the http host header

```yaml
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  components:
    pilot:
      k8s:
        overlays:
        - kind: Deployment
          name: istio-pilot
          patches:
          - path: spec.template.spec.containers.[name:discovery].args.[30m]
            value: "60m" # OVERRIDDEN
          - path: spec.template.spec.containers.[name:discovery].ports.[containerPort:8080].containerPort

  // MatchConditions is a list of conditions that must be met for a request to be sent to this
  // webhook. Match conditions filter requests that have already been matched by the rules,
  // namespaceSelector, and objectSelector. An empty list of matchConditions matches all requests.
  // There are a maximum of 64 match conditions allowed.
  //
  // The exact matching logic is (in order):

  // +optional
  optional string message = 4;
}

// An empty preferred scheduling term matches all objects with implicit weight 0
// (i.e. it's a no-op). A null preferred scheduling term matches no objects (i.e. is also a no-op).
message PreferredSchedulingTerm {
  // Weight associated with matching the corresponding nodeSelectorTerm, in the range 1-100.

Copyright (C) 2014-2019, Matt Butcher and Matt Farina

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is

  // Default to the empty LabelSelector, which matches everything.
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector objectSelector = 2;

  // ResourceRules describes what operations on what resources/subresources the ValidatingAdmissionPolicy matches.
  // The policy cares about an operation if it matches _any_ Rule.
  // +listType=atomic
  // +optional