message DaemonSetSpec {
  // A label query over pods that are managed by the daemon set.
  // Must match in order to be controlled.
  // It must match the pod template's labels.
  // More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 1;

  // An object that describes the pod that will be created.

CANONICAL_REVISION='latest'
CANONICAL_SERVICE='foo'
ISTIO_INBOUND_PORTS='*'
ISTIO_LOCAL_EXCLUDE_PORTS='22,15090,15021,15020'
ISTIO_METAJSON_LABELS='{"service.istio.io/canonical-name":"foo","service.istio.io/canonical-revision":"latest"}'
ISTIO_META_CLUSTER_ID='Kubernetes'
ISTIO_META_DNS_CAPTURE='true'
ISTIO_META_MESH_ID=''
ISTIO_META_NETWORK=''
ISTIO_META_WORKLOAD_NAME='foo'
ISTIO_NAMESPACE='bar'
ISTIO_SERVICE='foo.bar'
ISTIO_SERVICE_CIDR='*'

  // items is a list of schema objects.
  repeated RuntimeClass items = 2;
}

// Scheduling specifies the scheduling constraints for nodes supporting a
// RuntimeClass.
message Scheduling {
  // nodeSelector lists labels that must be present on nodes that support this
  // RuntimeClass. Pods using this RuntimeClass can only be scheduled to a
  // node matched by this selector. The RuntimeClass nodeSelector is merged

- `istio-iptables`
    - sets up iptables to redirect a list of ports to the port envoy will listen
    - shared code with istio-init container
    - it will generate an iptables-save config, based on annotations/labels and other settings, and apply it.

### CmdAdd Sidecar Workflow

`CmdAdd` is triggered when there is a new pod created. This runs on the node, in a chain of CNI plugins - Istio is

  // for more examples of label selectors.
  //
  // Default to the empty LabelSelector, which matches everything.
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector namespaceSelector = 5;

  // ObjectSelector decides whether to run the webhook based on if the
  // object has matching labels. objectSelector is evaluated against both

        prometheus.io/scrape: "true"
        sidecar.istio.io/status: '{"initContainers":["istio-init"],"containers":["istio-proxy"],"volumes":null,"imagePullSecrets":null,"revision":"default"}'
      creationTimestamp: null
      labels:
        app: hello
        tier: backend
        track: stable
    spec:
      containers:
      - image: fake.docker.io/google-samples/hello-go-gke:1.0
        name: hello
        ports:

CANONICAL_REVISION='latest'
CANONICAL_SERVICE='foo'
CA_ADDR='istiod-rev-1.istio-system.svc:15012'
CLUSTER_MESH_CONFIG_VALUE='foo'
ISTIO_INBOUND_PORTS='*'
ISTIO_LOCAL_EXCLUDE_PORTS='22,15090,15021,15020'
ISTIO_METAJSON_LABELS='{"service.istio.io/canonical-name":"foo","service.istio.io/canonical-revision":"latest"}'
ISTIO_META_CLUSTER_ID='Kubernetes'
ISTIO_META_DNS_CAPTURE='true'
ISTIO_META_MESH_ID=''
ISTIO_META_NETWORK=''
ISTIO_META_WORKLOAD_NAME='foo'

  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 4;

  // manualSelector controls generation of pod labels and pod selectors.
  // Leave `manualSelector` unset unless you are certain what you are doing.
  // When false or unset, the system pick labels unique to this job
  // and appends those labels to the pod template.  When true,

  // topology contains arbitrary topology information associated with the
  // endpoint. These key/value pairs must conform with the label format.
  // https://kubernetes.io/docs/concepts/overview/working-with-objects/labels
  // Topology may include a maximum of 16 key/value pairs. This includes, but
  // is not limited to the following well known keys:
  // * kubernetes.io/hostname: the value indicates the hostname of the node

  // * Exact: Matches the URL path exactly.
  // * Prefix: Matches based on a URL path prefix split by '/'. Matching is
  //   done on a path element by element basis. A path element refers is the
  //   list of labels in the path split by the '/' separator. A request is a
  //   match for path p if every p is an element-wise prefix of p of the
  //   request path. Note that if the last element of the path is a substring