meshConfig:
  defaultConfig:
    proxyMetadata:
      # Enable Istio agent to handle DNS requests for known hosts
      # Unknown hosts will automatically be resolved using upstream dns servers in resolv.conf

### 域名

第一步我们要先**获取**一些**域名(Domain Name)**。 然后可以在 DNS 服务器（可能是你的同一家云服务商提供的）中配置它。

你可能拥有一个云服务器（虚拟机）或类似的东西，并且它会有一个<abbr title="That isn't Change">固定</abbr> **公共IP地址**。

在 DNS 服务器中，你可以配置一条记录（“A 记录”）以将 **你的域名** 指向你服务器的公共 **IP 地址**。

这个操作一般只需要在最开始执行一次。

!!! tip
     域名这部分发生在 HTTPS 之前，由于这一切都依赖于域名和 IP 地址，所以先在这里提一下。

### DNS

现在让我们关注真正的 HTTPS 部分。

首先，浏览器将通过 **DNS 服务器** 查询**域名的IP** 是什么，在本例中为 `someapp.example.com`。

  // hostname of this endpoint. This field may be used by consumers of
  // endpoints to distinguish endpoints from each other (e.g. in DNS names).
  // Multiple endpoints which use the same hostname should be considered
  // fungible (e.g. multiple A values in DNS). Must be lowercase and pass DNS
  // Label (RFC 1123) validation.
  // +optional
  optional string hostname = 3;

      }

    /**
     * Sets the DNS service used to lookup IP addresses for hostnames.
     *
     * If unset, the [system-wide default][Dns.SYSTEM] DNS will be used.
     */
    fun dns(dns: Dns) =
      apply {
        if (dns != this.dns) {
          this.routeDatabase = null
        }
        this.dns = dns
      }

    /**

 * and {@link java.net.InetAddress}. The name resolution mechanisms
 * used will systematically query all available configured resolution
 * services including WINS, broadcasts, DNS, and LMHOSTS. See
 * <a href="../../resolver.html">Setting Name Resolution Properties</a>
 * and the <code>jcifs.resolveOrder</code> property. Changing
 * jCIFS name resolution properties can greatly affect the behavior of

  // hostname of this endpoint. This field may be used by consumers of
  // endpoints to distinguish endpoints from each other (e.g. in DNS names).
  // Multiple endpoints which use the same hostname should be considered
  // fungible (e.g. multiple A values in DNS). Must be lowercase and pass DNS
  // Label (RFC 1123) validation.
  // +optional
  optional string hostname = 3;

          secretName: cacerts
          optional: true
      - name: istio-kubeconfig
        secret:
          secretName: istio-kubeconfig
          optional: true
      # Optional: istio-csr dns pilot certs
      - name: istio-csr-dns-cert
        secret:
          secretName: istiod-tls
          optional: true
      - name: istio-csr-ca-configmap
        configMap:
          name: istio-ca-root-cert

   * address for all hosts, regardless of the actual number of IP addresses reported by DNS.
   */
  fun newClient(): OkHttpClient {
    var client = testClient
    if (client == null) {
      client =
        initialClientBuilder()
          .dns(SINGLE_INET_ADDRESS_DNS) // Prevent unexpected fallback addresses.
          .eventListenerFactory { ClientRuleEventListener(logger = ::addEvent) }

meshConfig:
  defaultConfig:
    proxyMetadata:
      # Enable Istio agent to handle DNS requests for known hosts
      # Unknown hosts will automatically be resolved using upstream dns servers in resolv.conf

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package dns

import (
	"encoding/json"
	"time"
)

const (
	defaultTTL            = 30
	defaultContextTimeout = 5 * time.Minute
)

// SrvRecord - represents a DNS service record
type SrvRecord struct {
	Host     string      `json:"host,omitempty"`
	Port     json.Number `json:"port,omitempty"`