The Istio CNI Node Agent is responsible for several things

- Install an Istio CNI plugin binary on each node's filesystem, updating that node's CNI config in e.g (`/etc/cni/net.d`), and watching the config and binary paths to reinstall if things are modified.

  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 1;

  // An object that describes the pod that will be created.
  // The DaemonSet will create exactly one copy of this pod on every node
  // that matches the template's node selector (or on every node if no node
  // selector is specified).
  // The only allowed template.spec.restartPolicy value is "Always".

  // +optional
  optional string path = 1;

  // pathType determines the interpretation of the path matching. PathType can
  // be one of the following values:
  // * 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

  // +optional
  optional string path = 1;

  // pathType determines the interpretation of the path matching. PathType can
  // be one of the following values:
  // * 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

}

// ResourcePolicyRule is a predicate that matches some resource
// requests, testing the request's verb and the target resource. A
// ResourcePolicyRule matches a resource request if and only if: (a)
// at least one member of verbs matches the request, (b) at least one
// member of apiGroups matches the request, (c) at least one member of
// resources matches the request, and (d) either (d1) the request does

}

// ResourcePolicyRule is a predicate that matches some resource
// requests, testing the request's verb and the target resource. A
// ResourcePolicyRule matches a resource request if and only if: (a)
// at least one member of verbs matches the request, (b) at least one
// member of apiGroups matches the request, (c) at least one member of
// resources matches the request, and (d) either (d1) the request does

  // Required
  optional string namespace = 1;

  // `name` is the name of the service.
  // Required
  optional string name = 2;

  // `path` is an optional URL path which will be sent in any request to
  // this service.
  // +optional
  optional string path = 3;

  // If specified, the port on the service that hosting webhook.
  // Default to 443 for backward compatibility.

                name: my-config-map
              name: my-volume-name
          - path: 'spec.template.spec.containers[0].volumeMounts[100]'
            value:
              mountPath: /mnt/path1
              name: my-volume-name
        - kind: Service
          name: istio-pilot
          patches:
          - path: spec.ports.[name:grpc-xds].port
            value: 15099 # OVERRIDDEN
```

message PodFailurePolicy {
  // A list of pod failure policy rules. The rules are evaluated in order.
  // Once a rule matches a Pod failure, the remaining of the rules are ignored.
  // When no rule matches the Pod failure, the default handling applies - the
  // counter of pod failures is incremented and it is checked against
  // the backoffLimit. At most 20 elements are allowed.

## Traffic routing

Based on the three [redirection](#redirection) paths, the ztunnel has three primary types of traffic it handles.

### Outbound

Requests leaving a pod go through the "outbound" code path on port 15001.
This is where most of Ztunnel's logic lives.

For outbound traffic, we need to first determine where the traffic is destined to.