Update gateway and sidecar hosts doc

networking/v1alpha3/gateway.proto

@@ -242,20 +242,30 @@ message Server {
   // abstract namespace).
   string bind = 4;
 
-  // REQUIRED. A list of hosts exposed by this gateway. At least one
-  // host is required. While typically applicable to
-  // HTTP services, it can also be used for TCP services using TLS with
-  // SNI. May contain a wildcard prefix for the bottom-level component of
-  // a domain name. For example `*.foo.com` matches `bar.foo.com`
-  // and `*.com` matches `bar.foo.com`, `example.com`, and so on.
+  // REQUIRED. One or more hosts exposed by this gateway.
+  // While typically applicable to
+  // HTTP services, it can also be used for TCP services using TLS with SNI.
+  // A host is specified as a `dnsName` with an optional `namespace/` prefix.
+  // The `dnsName` should be specified using FQDN format, opionally including
+  // a wildcard character in the left-most component (e.g., `prod/*.example.com`).
+  // Set the `dnsName` to `*` to select all `VirtualService` hosts from the
+  // specified namespace (e.g.,`prod/*`). If no `namespace/` is specified,
+  // the `VirtualService` hosts will be selected from any available namespace.
+  // Any associated `DestinationRule` in the same namespace will also be used.
   //
-  // **Note**: A `VirtualService` that is bound to a gateway must have one
-  // or more hosts that match the hosts specified in a server. The match
+  // A `VirtualService` must be bound to the gateway and must have one or
+  // more hosts that match the hosts specified in a server. The match
   // could be an exact match or a suffix match with the server's hosts. For
-  // example, if the server's hosts specifies "*.example.com",
-  // VirtualServices with hosts dev.example.com, prod.example.com will
-  // match. However, VirtualServices with hosts example.com or
-  // newexample.com will not match.
+  // example, if the server's hosts specifies `*.example.com`, a
+  // `VirtualService` with hosts `dev.example.com` or `prod.example.com` will
+  // match. However, a `VirtualService` with host `example.com` or
+  // `newexample.com` will not match.
+  //
+  // NOTE: Only virtual services exported to the gateway's namespace
+  // (e.g., `exportTo` value of `*`) can be referenced.
+  // Private configurations (e.g., `exportTo` set to `.`) will not be
+  // available. Refer to the `exportTo` setting in `VirtualService`,
+  // `DestinationRule`, and `ServiceEntry` configurations for details.
   repeated string hosts = 2;
 
   message TLSOptions {

networking/v1alpha3/sidecar.proto

@@ -178,24 +178,25 @@ message IstioEgressListener {
   // captureMode must be DEFAULT or NONE for Unix domain socket binds.
   CaptureMode capture_mode = 3;
 
-  // REQUIRED: One or more services/virtualServices exposed by the listener
-  // in namespace/dnsName format.  Publicly scoped services and
-  // VirtualServices from remote namespaces corresponding to the specified
-  // hosts will be imported. The service in a namespace can be a service in
-  // the service registry (e.g., a Kubernetes or cloud foundry service) or
-  // a service specified via ServiceEntry configuration. In addition, any
-  // publicly scoped DestinationRule associated with the imported services
-  // will also be imported.
+  // REQUIRED: One or more service hosts exposed by the listener
+  // in `namespace/dnsName` format. Services in the specified namespace
+  // matching `dnsName` will be exposed.
+  // The corresponding service can be a service in the service registry
+  // (e.g., a Kubernetes or cloud foundry service) or a service specified
+  // using a `ServiceEntry` or `VirtualService` configuration. Any
+  // associated `DestinationRule` in the same namespace will also be used.
   //
-  // Set the namespace to * to import a particular service from any
-  // available namespace (e.g., "*/foo.example.com"). Set the dnsName field
-  // to * to import all services from the specified namespace (e.g.,
-  // "prod/*"). The services should be specified using FQDN format.
+  // The `dnsName` should be specified using FQDN format, opionally including
+  // a wildcard character in the left-most component (e.g., `prod/*.example.com`).
+  // Set the `dnsName` to `*` to select all services from the specified namespace
+  // (e.g.,`prod/*`). The `namespace` can also be set to `*` to select a particular
+  // service from any available namespace (e.g., "*/foo.example.com").
   //
-  // NOTE: Only exported services and configuration artifacts from a
-  // namespace can be imported. Private services/configuration will not be
-  // imported. Refer to the scope setting associated with VirtualService,
-  // DestinationRule, ServiceEntry, etc. for details.
+  // NOTE: Only services and configuration artifacts exported to the sidecar's
+  // namespace (e.g., `exportTo` value of `*`) can be referenced.
+  // Private configurations (e.g., `exportTo` set to `.`) will
+  // not be available. Refer to the `exportTo` setting in `VirtualService`,
+  // `DestinationRule`, and `ServiceEntry` configurations for details.
   repeated string hosts = 4;
 }