1. Config ingestion (inputs to the system)
1. Config translation
1. Config serving (XDS)

### Config Ingestion

Istio reads from over 20 different resources types, and aggregates them together to build the proxy configuration. These resources can be sourced from Kubernetes (via watches), files, or over xDS; Kubernetes is by far the most common usage, though.

Primarily for historical reasons, ingestion is split into a few components.

  //
  // Well-known Kubernetes signers are:
  //  1. "kubernetes.io/kube-apiserver-client": issues client certificates that can be used to authenticate to kube-apiserver.
  //   Requests for this signer are never auto-approved by kube-controller-manager, can be issued by the "csrsigning" controller in kube-controller-manager.

  // A list of daemon sets.
  repeated DaemonSet items = 2;
}

// DaemonSetSpec is the specification of a daemon set.
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.

  // A list of daemon sets.
  repeated DaemonSet items = 2;
}

// DaemonSetSpec is the specification of a daemon set.
message DaemonSetSpec {
  // A label query over pods that are managed by the daemon set.
  // Must match in order to be controlled.
  // If empty, defaulted to labels on Pod template.

    # Setting this to `IfNeeded` will result in the sidecar injector being run again if additional mutations occur.
    reinvocationPolicy: Never
    rewriteAppHTTPProbe: true
    # Templates defines a set of custom injection templates that can be used. For example, defining:
    #
    # templates:
    #   hello: |
    #     metadata:
    #       labels:

					k := kube.EnableCrdWatcher(c.client)
					sa.AddRunningKubeSourceWithRevision(k, revisionSpecified, c.remote)
				}
			}

			// If we explicitly specify mesh config, use it.
			// This takes precedence over default mesh config or mesh config from a running Kube instance.
			if meshCfgFile != "" {
				_ = sa.AddFileKubeMeshConfig(meshCfgFile)
			}

					Revision: "default",
					Reason:   "The injection webhook is deactivated, and will never match labels.",
				},
			},
		},
	}
	whFiles := []string{
		"testdata/check-inject/default-injector.yaml",
		"testdata/check-inject/rev-16-injector.yaml",
		"testdata/check-inject/never-match-injector.yaml",
	}
	var whs []admitv1.MutatingWebhookConfiguration
	for _, whName := range whFiles {

			specifiedConfName: "bridge.conf",
			delayedConfName:   "bridge.conf",
			expectedConfName:  "bridge.conf",
		},
		{
			name:              "specified CNI config file never created",
			chainedCNIPlugin:  true,
			specifiedConfName: "never-created.conf",
			existingConfFiles: []string{"bridge.conf", "list.conflist"},
		},
		{
			name:             "standalone CNI plugin unspecified CNI config file",

            "lineInterpolation": "linear",
            "lineWidth": 1,
            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }

  // object itself is a namespace, the matching is performed on
  // object.metadata.labels. If the object is another cluster scoped resource,
  // it never skips the policy.
  //
  // For example, to run the webhook on any objects whose namespace is not
  // associated with "runlevel" of "0" or "1";  you will set the selector as
  // follows:
  // "namespaceSelector": {
  //   "matchExpressions": [