//
  // Validation requirements:
  //  1. certificate must contain one or more PEM blocks.
  //  2. All PEM blocks must have the "CERTIFICATE" label, contain no headers, and the encoded data
  //   must be a BER-encoded ASN.1 Certificate structure as described in section 4 of RFC5280.

#### Cluster Selection
* [alpha] Federation [ClusterSelector annotation](https://kubernetes.io/docs/tasks/administer-federation/cluster/#clusterselector-annotation) to direct objects to federated clusters with matching labels.


### **Instrumentation**
#### Core Metrics API

 *    no pinning will be enforced if additional prefixes are present, or if no prefixes are present.
 *
 * Note that any other form is unsupported. You may not use asterisks in any position other than
 * the leftmost label.
 *
 * If multiple patterns match a hostname, any match is sufficient. For example, suppose pin A
 * applies to `*.publicobject.com` and pin B applies to `api.publicobject.com`. Handshakes for

		Buckets: []float64{0.01, 0.1, 1, 2, 5, 10, 60, 5 * 60, 15 * 60, 30 * 60},
	}, []string{"tier"}),
}

func (t *tierMetrics) Observe(tier string, dur time.Duration) {
	t.histogram.With(prometheus.Labels{"tier": tier}).Observe(dur.Seconds())
}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat

* Reduce memory utilization of admission webhook metrics by removing resource related labels. ([#69895](https://github.com/kubernetes/kubernetes/pull/69895), [@jpbetz](https://github.com/jpbetz))

The `Proxy` as an input parameter is important, and a major distinction from some other XDS implementations. We are not able to statically translate inputs to XDS without per-client information. For example, we rely on the client's labels to determine the set of policies applied. While this is necessary to implement Istio's APIs, it does limit performance substantially.

#### Caching

        putResultDataBody(dataMap, Constants.INDEXING_TARGET, indexingTarget);
        //  boost
        putResultDataBody(dataMap, fessConfig.getIndexFieldBoost(), crawlingConfig.getDocumentBoost());
        // label: labelType
        final LabelTypeHelper labelTypeHelper = ComponentUtil.getLabelTypeHelper();
        putResultDataBody(dataMap, fessConfig.getIndexFieldLabel(), labelTypeHelper.getMatchedLabelValueSet(url));

            "ISTIO_PROXY_SHA": "ee85c5f28702f00621aed895915fca565796b9e4",
            "ISTIO_VERSION": "1.21.0-1226",
            "metadata": {
              "build.type": "RELEASE",
              "build.label": "dev",
              "revision.sha": "ee85c5f28702f00621aed895915fca565796b9e4",
              "revision.status": "Clean",
              "ssl.version": "BoringSSL"
            }
          }
        }
      },

 * Caffeine}</a> class. Caffeine offers better performance, more features (including asynchronous
 * loading), and fewer <a
 * href="https://github.com/google/guava/issues?q=is%3Aopen+is%3Aissue+label%3Apackage%3Dcache+label%3Atype%3Ddefect">bugs</a>.
 *
 * <p>Caffeine defines its own interfaces (<a

message MetricIdentifier {
  // name is the name of the given metric
  optional string name = 1;

  // selector is the string-encoded form of a standard kubernetes label selector for the given metric
  // When set, it is passed as an additional parameter to the metrics server for more specific metrics scoping.
  // When unset, just the metricName will be used to gather metrics.
  // +optional