istio.io/content/docs/reference/config/networking/v1alpha3/virtual-service/index.html

---
WARNING: THIS IS AN AUTO-GENERATED FILE, DO NOT EDIT. PLEASE MODIFY THE ORIGINAL SOURCE IN THE https://github.com/istio/api REPO
source_repo: https://github.com/istio/api
title: Virtual Service
description: Configuration affecting label/content routing, sni routing, etc.
location: https://istio.io/docs/reference/config/networking/v1alpha3/virtual-service.html
layout: protoc-gen-docs
generator: protoc-gen-docs
number_of_entries: 22
---
<p>Configuration affecting traffic routing. Here are a few terms useful to define
in the context of traffic routing.</p>

<p><code>Service</code> a unit of application behavior bound to a unique name in a
service registry. Services consist of multiple network <em>endpoints</em>
implemented by workload instances running on pods, containers, VMs etc.</p>

<p><code>Service versions (a.k.a. subsets)</code> - In a continuous deployment
scenario, for a given service, there can be distinct subsets of
instances running different variants of the application binary. These
variants are not necessarily different API versions. They could be
iterative changes to the same service, deployed in different
environments (prod, staging, dev, etc.). Common scenarios where this
occurs include A/B testing, canary rollouts, etc. The choice of a
particular version can be decided based on various criterion (headers,
url, etc.) and/or by weights assigned to each version. Each service has
a default version consisting of all its instances.</p>

<p><code>Source</code> - A downstream client calling a service.</p>

<p><code>Host</code> - The address used by a client when attempting to connect to a
service.</p>

<p><code>Access model</code> - Applications address only the destination service
(Host) without knowledge of individual service versions (subsets). The
actual choice of the version is determined by the proxy/sidecar, enabling the
application code to decouple itself from the evolution of dependent
services.</p>

<p>A <code>VirtualService</code> defines a set of traffic routing rules to apply when a host is
addressed. Each routing rule defines matching criteria for traffic of a specific
protocol. If the traffic is matched, then it is sent to a named destination service
(or subset/version of it) defined in the registry.</p>

<p>The source of traffic can also be matched in a routing rule. This allows routing
to be customized for specific client contexts.</p>

<p>The following example on Kubernetes, routes all HTTP traffic by default to
pods of the reviews service with label &ldquo;version: v1&rdquo;. In addition,
HTTP requests with path starting with /wpcatalog/ or /consumercatalog/ will
be rewritten to /newcatalog and sent to pods with label &ldquo;version: v2&rdquo;.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-route
spec:
  hosts:
  - reviews.prod.svc.cluster.local
  http:
  - match:
    - uri:
        prefix: &quot;/wpcatalog&quot;
    - uri:
        prefix: &quot;/consumercatalog&quot;
    rewrite:
      uri: &quot;/newcatalog&quot;
    route:
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v2
  - route:
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v1
</code></pre>

<p>A subset/version of a route destination is identified with a reference
to a named service subset which must be declared in a corresponding
<code>DestinationRule</code>.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews-destination
spec:
  host: reviews.prod.svc.cluster.local
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
</code></pre>

<h2 id="CorsPolicy">CorsPolicy</h2>
<section>
<p>Describes the Cross-Origin Resource Sharing (CORS) policy, for a given
service. Refer to <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS">CORS</a>
for further details about cross origin resource sharing. For example,
the following rule restricts cross origin requests to those originating
from example.com domain using HTTP POST/GET, and sets the
<code>Access-Control-Allow-Credentials</code> header to false. In addition, it only
exposes <code>X-Foo-bar</code> header and sets an expiry period of 1 day.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings-route
spec:
  hosts:
  - ratings.prod.svc.cluster.local
  http:
  - route:
    - destination:
        host: ratings.prod.svc.cluster.local
        subset: v1
    corsPolicy:
      allowOrigin:
      - example.com
      allowMethods:
      - POST
      - GET
      allowCredentials: false
      allowHeaders:
      - X-Foo-Bar
      maxAge: &quot;1d&quot;
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="CorsPolicy-allow_origin">
<td><code>allowOrigin</code></td>
<td><code>string[]</code></td>
<td>
<p>The list of origins that are allowed to perform CORS requests. The
content will be serialized into the Access-Control-Allow-Origin
header. Wildcard * will allow all origins.</p>

</td>
</tr>
<tr id="CorsPolicy-allow_methods">
<td><code>allowMethods</code></td>
<td><code>string[]</code></td>
<td>
<p>List of HTTP methods allowed to access the resource. The content will
be serialized into the Access-Control-Allow-Methods header.</p>

</td>
</tr>
<tr id="CorsPolicy-allow_headers">
<td><code>allowHeaders</code></td>
<td><code>string[]</code></td>
<td>
<p>List of HTTP headers that can be used when requesting the
resource. Serialized to Access-Control-Allow-Headers header.</p>

</td>
</tr>
<tr id="CorsPolicy-expose_headers">
<td><code>exposeHeaders</code></td>
<td><code>string[]</code></td>
<td>
<p>A white list of HTTP headers that the browsers are allowed to
access. Serialized into Access-Control-Expose-Headers header.</p>

</td>
</tr>
<tr id="CorsPolicy-max_age">
<td><code>maxAge</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration</a></code></td>
<td>
<p>Specifies how long the results of a preflight request can be
cached. Translates to the <code>Access-Control-Max-Age</code> header.</p>

</td>
</tr>
<tr id="CorsPolicy-allow_credentials">
<td><code>allowCredentials</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#boolvalue">google.protobuf.BoolValue</a></code></td>
<td>
<p>Indicates whether the caller is allowed to send the actual request
(not the preflight) using credentials. Translates to
<code>Access-Control-Allow-Credentials</code> header.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="Destination">Destination</h2>
<section>
<p>Destination indicates the network addressable service to which the
request/connection will be sent after processing a routing rule. The
destination.host should unambiguously refer to a service in the service
registry. Istio&rsquo;s service registry is composed of all the services found
in the platform&rsquo;s service registry (e.g., Kubernetes services, Consul
services), as well as services declared through the
<a href="/docs/reference/config/networking/v1alpha3/service-entry/#ServiceEntry">ServiceEntry</a> resource.</p>

<p><em>Note for Kubernetes users</em>: When short names are used (e.g. &ldquo;reviews&rdquo;
instead of &ldquo;reviews.default.svc.cluster.local&rdquo;), Istio will interpret
the short name based on the namespace of the rule, not the service. A
rule in the &ldquo;default&rdquo; namespace containing a host &ldquo;reviews will be
interpreted as &ldquo;reviews.default.svc.cluster.local&rdquo;, irrespective of the
actual namespace associated with the reviews service. <em>To avoid potential
misconfigurations, it is recommended to always use fully qualified
domain names over short names.</em></p>

<p>The following Kubernetes example routes all traffic by default to pods
of the reviews service with label &ldquo;version: v1&rdquo; (i.e., subset v1), and
some to subset v2, in a Kubernetes environment.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-route
  namespace: foo
spec:
  hosts:
  - reviews # interpreted as reviews.foo.svc.cluster.local
  http:
  - match:
    - uri:
        prefix: &quot;/wpcatalog&quot;
    - uri:
        prefix: &quot;/consumercatalog&quot;
    rewrite:
      uri: &quot;/newcatalog&quot;
    route:
    - destination:
        host: reviews # interpreted as reviews.foo.svc.cluster.local
        subset: v2
  - route:
    - destination:
        host: reviews # interpreted as reviews.foo.svc.cluster.local
        subset: v1
</code></pre>

<p>And the associated DestinationRule</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews-destination
  namespace: foo
spec:
  host: reviews # interpreted as reviews.foo.svc.cluster.local
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
</code></pre>

<p>The following VirtualService sets a timeout of 5s for all calls to
productpage.prod.svc.cluster.local service in Kubernetes. Notice that
there are no subsets defined in this rule. Istio will fetch all
instances of productpage.prod.svc.cluster.local service from the service
registry and populate the sidecar&rsquo;s load balancing pool. Also, notice
that this rule is set in the istio-system namespace but uses the fully
qualified domain name of the productpage service,
productpage.prod.svc.cluster.local. Therefore the rule&rsquo;s namespace does
not have an impact in resolving the name of the productpage service.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: my-productpage-rule
  namespace: istio-system
spec:
  hosts:
  - productpage.prod.svc.cluster.local # ignores rule namespace
  http:
  - timeout: 5s
    route:
    - destination:
        host: productpage.prod.svc.cluster.local
</code></pre>

<p>To control routing for traffic bound to services outside the mesh, external
services must first be added to Istio&rsquo;s internal service registry using the
ServiceEntry resource. VirtualServices can then be defined to control traffic
bound to these external services. For example, the following rules define a
Service for wikipedia.org and set a timeout of 5s for http requests.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-wikipedia
spec:
  hosts:
  - wikipedia.org
  location: MESH_EXTERNAL
  ports:
  - number: 80
    name: example-http
    protocol: HTTP
  resolution: DNS

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: my-wiki-rule
spec:
  hosts:
  - wikipedia.org
  http:
  - timeout: 5s
    route:
    - destination:
        host: wikipedia.org
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="Destination-host">
<td><code>host</code></td>
<td><code>string</code></td>
<td>
<p>REQUIRED. The name of a service from the service registry. Service
names are looked up from the platform&rsquo;s service registry (e.g.,
Kubernetes services, Consul services, etc.) and from the hosts
declared by <a href="/docs/reference/config/networking/v1alpha3/service-entry/#ServiceEntry">ServiceEntry</a>. Traffic forwarded to
destinations that are not found in either of the two, will be dropped.</p>

<p><em>Note for Kubernetes users</em>: When short names are used (e.g. &ldquo;reviews&rdquo;
instead of &ldquo;reviews.default.svc.cluster.local&rdquo;), Istio will interpret
the short name based on the namespace of the rule, not the service. A
rule in the &ldquo;default&rdquo; namespace containing a host &ldquo;reviews will be
interpreted as &ldquo;reviews.default.svc.cluster.local&rdquo;, irrespective of
the actual namespace associated with the reviews service. <em>To avoid
potential misconfigurations, it is recommended to always use fully
qualified domain names over short names.</em></p>

</td>
</tr>
<tr id="Destination-subset">
<td><code>subset</code></td>
<td><code>string</code></td>
<td>
<p>The name of a subset within the service. Applicable only to services
within the mesh. The subset must be defined in a corresponding
DestinationRule.</p>

</td>
</tr>
<tr id="Destination-port">
<td><code>port</code></td>
<td><code><a href="#PortSelector">PortSelector</a></code></td>
<td>
<p>Specifies the port on the host that is being addressed. If a service
exposes only a single port it is not required to explicitly select the
port.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPFaultInjection">HTTPFaultInjection</h2>
<section>
<p>HTTPFaultInjection can be used to specify one or more faults to inject
while forwarding http requests to the destination specified in a route.
Fault specification is part of a VirtualService rule. Faults include
aborting the Http request from downstream service, and/or delaying
proxying of requests. A fault rule MUST HAVE delay or abort or both.</p>

<p><em>Note:</em> Delay and abort faults are independent of one another, even if
both are specified simultaneously.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPFaultInjection-delay">
<td><code>delay</code></td>
<td><code><a href="#HTTPFaultInjection-Delay">HTTPFaultInjection.Delay</a></code></td>
<td>
<p>Delay requests before forwarding, emulating various failures such as
network issues, overloaded upstream service, etc.</p>

</td>
</tr>
<tr id="HTTPFaultInjection-abort">
<td><code>abort</code></td>
<td><code><a href="#HTTPFaultInjection-Abort">HTTPFaultInjection.Abort</a></code></td>
<td>
<p>Abort Http request attempts and return error codes back to downstream
service, giving the impression that the upstream service is faulty.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPFaultInjection-Abort">HTTPFaultInjection.Abort</h2>
<section>
<p>Abort specification is used to prematurely abort a request with a
pre-specified error code. The following example will return an HTTP 400
error code for 1 out of every 1000 requests to the &ldquo;ratings&rdquo; service &ldquo;v1&rdquo;.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings-route
spec:
  hosts:
  - ratings.prod.svc.cluster.local
  http:
  - route:
    - destination:
        host: ratings.prod.svc.cluster.local
        subset: v1
    fault:
      abort:
        percentage:
          value: 0.001
        httpStatus: 400
</code></pre>

<p>The <em>httpStatus</em> field is used to indicate the HTTP status code to
return to the caller. The optional <em>percentage</em> field can be used to only
abort a certain percentage of requests. If not specified, all requests are
aborted.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPFaultInjection-Abort-percent" class="deprecated ">
<td><code>percent</code></td>
<td><code>int32</code></td>
<td>
<p>Percentage of requests to be aborted with the error code provided (0-100).
Use of integer <code>percent</code> value is deprecated. Use the double <code>percentage</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPFaultInjection-Abort-http_status" class="oneof oneof-start">
<td><code>httpStatus</code></td>
<td><code>int32 (oneof)</code></td>
<td>
<p>REQUIRED. HTTP status code to use to abort the Http request.</p>

</td>
</tr>
<tr id="HTTPFaultInjection-Abort-percentage">
<td><code>percentage</code></td>
<td><code><a href="#Percent">Percent</a></code></td>
<td>
<p>Percentage of requests to be aborted with the error code provided.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPFaultInjection-Delay">HTTPFaultInjection.Delay</h2>
<section>
<p>Delay specification is used to inject latency into the request
forwarding path. The following example will introduce a 5 second delay
in 1 out of every 1000 requests to the &ldquo;v1&rdquo; version of the &ldquo;reviews&rdquo;
service from all pods with label env: prod</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-route
spec:
  hosts:
  - reviews.prod.svc.cluster.local
  http:
  - match:
    - sourceLabels:
        env: prod
    route:
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v1
    fault:
      delay:
        percentage:
          value: 0.001
        fixedDelay: 5s
</code></pre>

<p>The <em>fixedDelay</em> field is used to indicate the amount of delay in seconds.
The optional <em>percentage</em> field can be used to only delay a certain
percentage of requests. If left unspecified, all request will be delayed.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPFaultInjection-Delay-percent" class="deprecated ">
<td><code>percent</code></td>
<td><code>int32</code></td>
<td>
<p>Percentage of requests on which the delay will be injected (0-100).
Use of integer <code>percent</code> value is deprecated. Use the double <code>percentage</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPFaultInjection-Delay-fixed_delay" class="oneof oneof-start">
<td><code>fixedDelay</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration (oneof)</a></code></td>
<td>
<p>REQUIRED. Add a fixed delay before forwarding the request. Format:
1h/1m/1s/1ms. MUST be &gt;=1ms.</p>

</td>
</tr>
<tr id="HTTPFaultInjection-Delay-percentage">
<td><code>percentage</code></td>
<td><code><a href="#Percent">Percent</a></code></td>
<td>
<p>Percentage of requests on which the delay will be injected.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPMatchRequest">HTTPMatchRequest</h2>
<section>
<p>HttpMatchRequest specifies a set of criterion to be met in order for the
rule to be applied to the HTTP request. For example, the following
restricts the rule to match only requests where the URL path
starts with /ratings/v2/ and the request contains a custom <code>end-user</code> header
with value <code>jason</code>.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings-route
spec:
  hosts:
  - ratings.prod.svc.cluster.local
  http:
  - match:
    - headers:
        end-user:
          exact: jason
      uri:
        prefix: &quot;/ratings/v2/&quot;
    route:
    - destination:
        host: ratings.prod.svc.cluster.local
</code></pre>

<p>HTTPMatchRequest CANNOT be empty.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPMatchRequest-uri">
<td><code>uri</code></td>
<td><code><a href="#StringMatch">StringMatch</a></code></td>
<td>
<p>URI to match
values are case-sensitive and formatted as follows:</p>

<ul>
<li><p><code>exact: &quot;value&quot;</code> for exact string match</p></li>

<li><p><code>prefix: &quot;value&quot;</code> for prefix-based match</p></li>

<li><p><code>regex: &quot;value&quot;</code> for ECMAscript style regex-based match</p></li>
</ul>

</td>
</tr>
<tr id="HTTPMatchRequest-scheme">
<td><code>scheme</code></td>
<td><code><a href="#StringMatch">StringMatch</a></code></td>
<td>
<p>URI Scheme
values are case-sensitive and formatted as follows:</p>

<ul>
<li><p><code>exact: &quot;value&quot;</code> for exact string match</p></li>

<li><p><code>prefix: &quot;value&quot;</code> for prefix-based match</p></li>

<li><p><code>regex: &quot;value&quot;</code> for ECMAscript style regex-based match</p></li>
</ul>

</td>
</tr>
<tr id="HTTPMatchRequest-method">
<td><code>method</code></td>
<td><code><a href="#StringMatch">StringMatch</a></code></td>
<td>
<p>HTTP Method
values are case-sensitive and formatted as follows:</p>

<ul>
<li><p><code>exact: &quot;value&quot;</code> for exact string match</p></li>

<li><p><code>prefix: &quot;value&quot;</code> for prefix-based match</p></li>

<li><p><code>regex: &quot;value&quot;</code> for ECMAscript style regex-based match</p></li>
</ul>

</td>
</tr>
<tr id="HTTPMatchRequest-authority">
<td><code>authority</code></td>
<td><code><a href="#StringMatch">StringMatch</a></code></td>
<td>
<p>HTTP Authority
values are case-sensitive and formatted as follows:</p>

<ul>
<li><p><code>exact: &quot;value&quot;</code> for exact string match</p></li>

<li><p><code>prefix: &quot;value&quot;</code> for prefix-based match</p></li>

<li><p><code>regex: &quot;value&quot;</code> for ECMAscript style regex-based match</p></li>
</ul>

</td>
</tr>
<tr id="HTTPMatchRequest-headers">
<td><code>headers</code></td>
<td><code>map&lt;string,&nbsp;<a href="#StringMatch">StringMatch</a>&gt;</code></td>
<td>
<p>The header keys must be lowercase and use hyphen as the separator,
e.g. <em>x-request-id</em>.</p>

<p>Header values are case-sensitive and formatted as follows:</p>

<ul>
<li><p><code>exact: &quot;value&quot;</code> for exact string match</p></li>

<li><p><code>prefix: &quot;value&quot;</code> for prefix-based match</p></li>

<li><p><code>regex: &quot;value&quot;</code> for ECMAscript style regex-based match</p></li>
</ul>

<p><strong>Note:</strong> The keys <code>uri</code>, <code>scheme</code>, <code>method</code>, and <code>authority</code> will be ignored.</p>

</td>
</tr>
<tr id="HTTPMatchRequest-port">
<td><code>port</code></td>
<td><code>uint32</code></td>
<td>
<p>Specifies the ports on the host that is being addressed. Many services
only expose a single port or label ports with the protocols they support,
in these cases it is not required to explicitly select the port.</p>

</td>
</tr>
<tr id="HTTPMatchRequest-source_labels">
<td><code>sourceLabels</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>One or more labels that constrain the applicability of a rule to
workloads with the given labels. If the VirtualService has a list of
gateways specified at the top, it should include the reserved gateway
<code>mesh</code> in order for this field to be applicable.</p>

</td>
</tr>
<tr id="HTTPMatchRequest-gateways">
<td><code>gateways</code></td>
<td><code>string[]</code></td>
<td>
<p>Names of gateways where the rule should be applied to. Gateway names
at the top of the VirtualService (if any) are overridden. The gateway match is
independent of sourceLabels.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPRedirect">HTTPRedirect</h2>
<section>
<p>HTTPRedirect can be used to send a 301 redirect response to the caller,
where the Authority/Host and the URI in the response can be swapped with
the specified values. For example, the following rule redirects
requests for /v1/getProductRatings API on the ratings service to
/v1/bookRatings provided by the bookratings service.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings-route
spec:
  hosts:
  - ratings.prod.svc.cluster.local
  http:
  - match:
    - uri:
        exact: /v1/getProductRatings
  redirect:
    uri: /v1/bookRatings
    authority: newratings.default.svc.cluster.local
  ...
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPRedirect-uri">
<td><code>uri</code></td>
<td><code>string</code></td>
<td>
<p>On a redirect, overwrite the Path portion of the URL with this
value. Note that the entire path will be replaced, irrespective of the
request URI being matched as an exact path or prefix.</p>

</td>
</tr>
<tr id="HTTPRedirect-authority">
<td><code>authority</code></td>
<td><code>string</code></td>
<td>
<p>On a redirect, overwrite the Authority/Host portion of the URL with
this value.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPRetry">HTTPRetry</h2>
<section>
<p>Describes the retry policy to use when a HTTP request fails. For
example, the following rule sets the maximum number of retries to 3 when
calling ratings:v1 service, with a 2s timeout per retry attempt.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings-route
spec:
  hosts:
  - ratings.prod.svc.cluster.local
  http:
  - route:
    - destination:
        host: ratings.prod.svc.cluster.local
        subset: v1
    retries:
      attempts: 3
      perTryTimeout: 2s
      retryOn: gateway-error,connect-failure,refused-stream
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPRetry-attempts">
<td><code>attempts</code></td>
<td><code>int32</code></td>
<td>
<p>REQUIRED. Number of retries for a given request. The interval
between retries will be determined automatically (25ms+). Actual
number of retries attempted depends on the httpReqTimeout.</p>

</td>
</tr>
<tr id="HTTPRetry-per_try_timeout">
<td><code>perTryTimeout</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration</a></code></td>
<td>
<p>Timeout per retry attempt for a given request. format: 1h/1m/1s/1ms. MUST BE &gt;=1ms.</p>

</td>
</tr>
<tr id="HTTPRetry-retry_on">
<td><code>retryOn</code></td>
<td><code>string</code></td>
<td>
<p>Specifies the conditions under which retry takes place.
One or more policies can be specified using a ‘,’ delimited list.
See the <a href="https://www.envoyproxy.io/docs/envoy/latest/configuration/http_filters/router_filter#x-envoy-retry-on">supported policies</a>
and <a href="https://www.envoyproxy.io/docs/envoy/latest/configuration/http_filters/router_filter#x-envoy-retry-grpc-on">here</a> for more details.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPRewrite">HTTPRewrite</h2>
<section>
<p>HTTPRewrite can be used to rewrite specific parts of a HTTP request
before forwarding the request to the destination. Rewrite primitive can
be used only with HTTPRouteDestination. The following example
demonstrates how to rewrite the URL prefix for api call (/ratings) to
ratings service before making the actual API call.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings-route
spec:
  hosts:
  - ratings.prod.svc.cluster.local
  http:
  - match:
    - uri:
        prefix: /ratings
    rewrite:
      uri: /v1/bookRatings
    route:
    - destination:
        host: ratings.prod.svc.cluster.local
        subset: v1
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPRewrite-uri">
<td><code>uri</code></td>
<td><code>string</code></td>
<td>
<p>rewrite the path (or the prefix) portion of the URI with this
value. If the original URI was matched based on prefix, the value
provided in this field will replace the corresponding matched prefix.</p>

</td>
</tr>
<tr id="HTTPRewrite-authority">
<td><code>authority</code></td>
<td><code>string</code></td>
<td>
<p>rewrite the Authority/Host header with this value.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPRoute">HTTPRoute</h2>
<section>
<p>Describes match conditions and actions for routing HTTP/1.1, HTTP2, and
gRPC traffic. See VirtualService for usage examples.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPRoute-match">
<td><code>match</code></td>
<td><code><a href="#HTTPMatchRequest">HTTPMatchRequest[]</a></code></td>
<td>
<p>Match conditions to be satisfied for the rule to be
activated. All conditions inside a single match block have AND
semantics, while the list of match blocks have OR semantics. The rule
is matched if any one of the match blocks succeed.</p>

</td>
</tr>
<tr id="HTTPRoute-route">
<td><code>route</code></td>
<td><code><a href="#HTTPRouteDestination">HTTPRouteDestination[]</a></code></td>
<td>
<p>A http rule can either redirect or forward (default) traffic. The
forwarding target can be one of several versions of a service (see
glossary in beginning of document). Weights associated with the
service version determine the proportion of traffic it receives.</p>

</td>
</tr>
<tr id="HTTPRoute-redirect">
<td><code>redirect</code></td>
<td><code><a href="#HTTPRedirect">HTTPRedirect</a></code></td>
<td>
<p>A http rule can either redirect or forward (default) traffic. If
traffic passthrough option is specified in the rule,
route/redirect will be ignored. The redirect primitive can be used to
send a HTTP 301 redirect to a different URI or Authority.</p>

</td>
</tr>
<tr id="HTTPRoute-rewrite">
<td><code>rewrite</code></td>
<td><code><a href="#HTTPRewrite">HTTPRewrite</a></code></td>
<td>
<p>Rewrite HTTP URIs and Authority headers. Rewrite cannot be used with
Redirect primitive. Rewrite will be performed before forwarding.</p>

</td>
</tr>
<tr id="HTTPRoute-timeout">
<td><code>timeout</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration</a></code></td>
<td>
<p>Timeout for HTTP requests.</p>

</td>
</tr>
<tr id="HTTPRoute-retries">
<td><code>retries</code></td>
<td><code><a href="#HTTPRetry">HTTPRetry</a></code></td>
<td>
<p>Retry policy for HTTP requests.</p>

</td>
</tr>
<tr id="HTTPRoute-fault">
<td><code>fault</code></td>
<td><code><a href="#HTTPFaultInjection">HTTPFaultInjection</a></code></td>
<td>
<p>Fault injection policy to apply on HTTP traffic at the client side.
Note that timeouts or retries will not be enabled when faults are
enabled on the client side.</p>

</td>
</tr>
<tr id="HTTPRoute-mirror">
<td><code>mirror</code></td>
<td><code><a href="#Destination">Destination</a></code></td>
<td>
<p>Mirror HTTP traffic to a another destination in addition to forwarding
the requests to the intended destination. Mirrored traffic is on a
best effort basis where the sidecar/gateway will not wait for the
mirrored cluster to respond before returning the response from the
original destination.  Statistics will be generated for the mirrored
destination.</p>

</td>
</tr>
<tr id="HTTPRoute-cors_policy">
<td><code>corsPolicy</code></td>
<td><code><a href="#CorsPolicy">CorsPolicy</a></code></td>
<td>
<p>Cross-Origin Resource Sharing policy (CORS). Refer to
<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS">CORS</a>
for further details about cross origin resource sharing.</p>

</td>
</tr>
<tr id="HTTPRoute-append_headers" class="deprecated ">
<td><code>appendHeaders</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Use of <code>append_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRoute-remove_response_headers" class="deprecated ">
<td><code>removeResponseHeaders</code></td>
<td><code>string[]</code></td>
<td>
<p>Use of <code>remove_response_header</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRoute-append_response_headers" class="deprecated ">
<td><code>appendResponseHeaders</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Use of <code>append_response_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRoute-remove_request_headers" class="deprecated ">
<td><code>removeRequestHeaders</code></td>
<td><code>string[]</code></td>
<td>
<p>Use of <code>remove_request_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRoute-append_request_headers" class="deprecated ">
<td><code>appendRequestHeaders</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Use of <code>append_request_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRoute-headers">
<td><code>headers</code></td>
<td><code><a href="#Headers">Headers</a></code></td>
<td>
<p>Header manipulation rules</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="HTTPRouteDestination">HTTPRouteDestination</h2>
<section>
<p>Each routing rule is associated with one or more service versions (see
glossary in beginning of document). Weights associated with the version
determine the proportion of traffic it receives. For example, the
following rule will route 25% of traffic for the &ldquo;reviews&rdquo; service to
instances with the &ldquo;v2&rdquo; tag and the remaining traffic (i.e., 75%) to
&ldquo;v1&rdquo;.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-route
spec:
  hosts:
  - reviews.prod.svc.cluster.local
  http:
  - route:
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v2
      weight: 25
    - destination:
        host: reviews.prod.svc.cluster.local
        subset: v1
      weight: 75
</code></pre>

<p>And the associated DestinationRule</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews-destination
spec:
  host: reviews.prod.svc.cluster.local
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
</code></pre>

<p>Traffic can also be split across two entirely different services without
having to define new subsets. For example, the following rule forwards 25% of
traffic to reviews.com to dev.reviews.com</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-route-two-domains
spec:
  hosts:
  - reviews.com
  http:
  - route:
    - destination:
        host: dev.reviews.com
      weight: 25
    - destination:
        host: reviews.com
      weight: 75
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="HTTPRouteDestination-destination">
<td><code>destination</code></td>
<td><code><a href="#Destination">Destination</a></code></td>
<td>
<p>REQUIRED. Destination uniquely identifies the instances of a service
to which the request/connection should be forwarded to.</p>

</td>
</tr>
<tr id="HTTPRouteDestination-weight">
<td><code>weight</code></td>
<td><code>int32</code></td>
<td>
<p>REQUIRED. The proportion of traffic to be forwarded to the service
version. (0-100). Sum of weights across destinations SHOULD BE == 100.
If there is only one destination in a rule, the weight value is assumed to
be 100.</p>

</td>
</tr>
<tr id="HTTPRouteDestination-remove_response_headers" class="deprecated ">
<td><code>removeResponseHeaders</code></td>
<td><code>string[]</code></td>
<td>
<p>Use of <code>remove_response_header</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRouteDestination-append_response_headers" class="deprecated ">
<td><code>appendResponseHeaders</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Use of <code>append_response_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRouteDestination-remove_request_headers" class="deprecated ">
<td><code>removeRequestHeaders</code></td>
<td><code>string[]</code></td>
<td>
<p>Use of <code>remove_request_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRouteDestination-append_request_headers" class="deprecated ">
<td><code>appendRequestHeaders</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Use of <code>append_request_headers</code> is deprecated. Use the <code>headers</code>
field instead.</p>

</td>
</tr>
<tr id="HTTPRouteDestination-headers">
<td><code>headers</code></td>
<td><code><a href="#Headers">Headers</a></code></td>
<td>
<p>Header manipulation rules</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="Headers">Headers</h2>
<section>
<p>Header manipulation rules</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="Headers-request">
<td><code>request</code></td>
<td><code><a href="#Headers-HeaderOperations">Headers.HeaderOperations</a></code></td>
<td>
<p>Header manipulation rules to apply before forwarding a request
to the destination service</p>

</td>
</tr>
<tr id="Headers-response">
<td><code>response</code></td>
<td><code><a href="#Headers-HeaderOperations">Headers.HeaderOperations</a></code></td>
<td>
<p>Header manipulation rules to apply before returning a response
to the caller</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="Headers-HeaderOperations">Headers.HeaderOperations</h2>
<section>
<p>HeaderOperations Describes the header manipulations to apply</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="Headers-HeaderOperations-set">
<td><code>set</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Overwrite the headers specified by key with the given values</p>

</td>
</tr>
<tr id="Headers-HeaderOperations-add">
<td><code>add</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>Append the given values to the headers specified by keys
(will create a comma-separated list of values)</p>

</td>
</tr>
<tr id="Headers-HeaderOperations-remove">
<td><code>remove</code></td>
<td><code>string[]</code></td>
<td>
<p>Remove a the specified headers</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="L4MatchAttributes">L4MatchAttributes</h2>
<section>
<p>L4 connection match attributes. Note that L4 connection matching support
is incomplete.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="L4MatchAttributes-destination_subnets">
<td><code>destinationSubnets</code></td>
<td><code>string[]</code></td>
<td>
<p>IPv4 or IPv6 ip addresses of destination with optional subnet.  E.g.,
a.b.c.d/xx form or just a.b.c.d.</p>

</td>
</tr>
<tr id="L4MatchAttributes-port">
<td><code>port</code></td>
<td><code>uint32</code></td>
<td>
<p>Specifies the port on the host that is being addressed. Many services
only expose a single port or label ports with the protocols they support,
in these cases it is not required to explicitly select the port.</p>

</td>
</tr>
<tr id="L4MatchAttributes-source_labels">
<td><code>sourceLabels</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>One or more labels that constrain the applicability of a rule to
workloads with the given labels. If the VirtualService has a list of
gateways specified at the top, it should include the reserved gateway
<code>mesh</code> in order for this field to be applicable.</p>

</td>
</tr>
<tr id="L4MatchAttributes-gateways">
<td><code>gateways</code></td>
<td><code>string[]</code></td>
<td>
<p>Names of gateways where the rule should be applied to. Gateway names
at the top of the VirtualService (if any) are overridden. The gateway
match is independent of sourceLabels.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="Percent">Percent</h2>
<section>
<p>Percent specifies a percentage in the range of [0.0, 100.0].</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="Percent-value">
<td><code>value</code></td>
<td><code>double</code></td>
<td>
</td>
</tr>
</tbody>
</table>
</section>
<h2 id="PortSelector">PortSelector</h2>
<section>
<p>PortSelector specifies the number of a port to be used for
matching or selection for final routing.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="PortSelector-number" class="oneof oneof-start">
<td><code>number</code></td>
<td><code>uint32 (oneof)</code></td>
<td>
<p>Valid port number</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="RouteDestination">RouteDestination</h2>
<section>
<p>L4 routing rule weighted destination.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="RouteDestination-destination">
<td><code>destination</code></td>
<td><code><a href="#Destination">Destination</a></code></td>
<td>
<p>REQUIRED. Destination uniquely identifies the instances of a service
to which the request/connection should be forwarded to.</p>

</td>
</tr>
<tr id="RouteDestination-weight">
<td><code>weight</code></td>
<td><code>int32</code></td>
<td>
<p>REQUIRED. The proportion of traffic to be forwarded to the service
version. If there is only one destination in a rule, all traffic will be
routed to it irrespective of the weight.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="StringMatch">StringMatch</h2>
<section>
<p>Describes how to match a given string in HTTP headers. Match is
case-sensitive.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="StringMatch-exact" class="oneof oneof-start">
<td><code>exact</code></td>
<td><code>string (oneof)</code></td>
<td>
<p>exact string match</p>

</td>
</tr>
<tr id="StringMatch-prefix" class="oneof">
<td><code>prefix</code></td>
<td><code>string (oneof)</code></td>
<td>
<p>prefix-based match</p>

</td>
</tr>
<tr id="StringMatch-regex" class="oneof">
<td><code>regex</code></td>
<td><code>string (oneof)</code></td>
<td>
<p>ECMAscript style regex-based match</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="TCPRoute">TCPRoute</h2>
<section>
<p>Describes match conditions and actions for routing TCP traffic. The
following routing rule forwards traffic arriving at port 27017 for
mongo.prod.svc.cluster.local to another Mongo server on port 5555.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: bookinfo-Mongo
spec:
  hosts:
  - mongo.prod.svc.cluster.local
  tcp:
  - match:
    - port: 27017
    route:
    - destination:
        host: mongo.backup.svc.cluster.local
        port:
          number: 5555
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="TCPRoute-match">
<td><code>match</code></td>
<td><code><a href="#L4MatchAttributes">L4MatchAttributes[]</a></code></td>
<td>
<p>Match conditions to be satisfied for the rule to be
activated. All conditions inside a single match block have AND
semantics, while the list of match blocks have OR semantics. The rule
is matched if any one of the match blocks succeed.</p>

</td>
</tr>
<tr id="TCPRoute-route">
<td><code>route</code></td>
<td><code><a href="#RouteDestination">RouteDestination[]</a></code></td>
<td>
<p>The destination to which the connection should be forwarded to.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="TLSMatchAttributes">TLSMatchAttributes</h2>
<section>
<p>TLS connection match attributes.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="TLSMatchAttributes-sni_hosts">
<td><code>sniHosts</code></td>
<td><code>string[]</code></td>
<td>
<p>REQUIRED. SNI (server name indicator) to match on. Wildcard prefixes
can be used in the SNI value, e.g., *.com will match foo.example.com
as well as example.com. An SNI value must be a subset (i.e., fall
within the domain) of the corresponding virtual serivce&rsquo;s hosts.</p>

</td>
</tr>
<tr id="TLSMatchAttributes-destination_subnets">
<td><code>destinationSubnets</code></td>
<td><code>string[]</code></td>
<td>
<p>IPv4 or IPv6 ip addresses of destination with optional subnet.  E.g.,
a.b.c.d/xx form or just a.b.c.d.</p>

</td>
</tr>
<tr id="TLSMatchAttributes-port">
<td><code>port</code></td>
<td><code>uint32</code></td>
<td>
<p>Specifies the port on the host that is being addressed. Many services
only expose a single port or label ports with the protocols they
support, in these cases it is not required to explicitly select the
port.</p>

</td>
</tr>
<tr id="TLSMatchAttributes-source_labels">
<td><code>sourceLabels</code></td>
<td><code>map&lt;string,&nbsp;string&gt;</code></td>
<td>
<p>One or more labels that constrain the applicability of a rule to
workloads with the given labels. If the VirtualService has a list of
gateways specified at the top, it should include the reserved gateway
<code>mesh</code> in order for this field to be applicable.</p>

</td>
</tr>
<tr id="TLSMatchAttributes-gateways">
<td><code>gateways</code></td>
<td><code>string[]</code></td>
<td>
<p>Names of gateways where the rule should be applied to. Gateway names
at the top of the VirtualService (if any) are overridden. The gateway
match is independent of sourceLabels.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="TLSRoute">TLSRoute</h2>
<section>
<p>Describes match conditions and actions for routing unterminated TLS
traffic (TLS/HTTPS) The following routing rule forwards unterminated TLS
traffic arriving at port 443 of gateway called &ldquo;mygateway&rdquo; to internal
services in the mesh based on the SNI value.</p>

<pre><code class="language-yaml">apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: bookinfo-sni
spec:
  hosts:
  - &quot;*.bookinfo.com&quot;
  gateways:
  - mygateway
  tls:
  - match:
    - port: 443
      sniHosts:
      - login.bookinfo.com
    route:
    - destination:
        host: login.prod.svc.cluster.local
  - match:
    - port: 443
      sniHosts:
      - reviews.bookinfo.com
    route:
    - destination:
        host: reviews.prod.svc.cluster.local
</code></pre>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="TLSRoute-match">
<td><code>match</code></td>
<td><code><a href="#TLSMatchAttributes">TLSMatchAttributes[]</a></code></td>
<td>
<p>REQUIRED. Match conditions to be satisfied for the rule to be
activated. All conditions inside a single match block have AND
semantics, while the list of match blocks have OR semantics. The rule
is matched if any one of the match blocks succeed.</p>

</td>
</tr>
<tr id="TLSRoute-route">
<td><code>route</code></td>
<td><code><a href="#RouteDestination">RouteDestination[]</a></code></td>
<td>
<p>The destination to which the connection should be forwarded to.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="VirtualService">VirtualService</h2>
<section>
<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="VirtualService-hosts">
<td><code>hosts</code></td>
<td><code>string[]</code></td>
<td>
<p>REQUIRED. The destination hosts to which traffic is being sent. Could
be a DNS name with wildcard prefix or an IP address.  Depending on the
platform, short-names can also be used instead of a FQDN (i.e. has no
dots in the name). In such a scenario, the FQDN of the host would be
derived based on the underlying platform.</p>

<p><strong>A host name can be defined by only one VirtualService</strong>. A single
VirtualService can be used to describe traffic properties for multiple
HTTP and TCP ports.</p>

<p><em>Note for Kubernetes users</em>: When short names are used (e.g. &ldquo;reviews&rdquo;
instead of &ldquo;reviews.default.svc.cluster.local&rdquo;), Istio will interpret
the short name based on the namespace of the rule, not the service. A
rule in the &ldquo;default&rdquo; namespace containing a host &ldquo;reviews will be
interpreted as &ldquo;reviews.default.svc.cluster.local&rdquo;, irrespective of
the actual namespace associated with the reviews service. <em>To avoid
potential misconfigurations, it is recommended to always use fully
qualified domain names over short names.</em></p>

<p>The hosts field applies to both HTTP and TCP services. Service inside
the mesh, i.e., those found in the service registry, must always be
referred to using their alphanumeric names. IP addresses are allowed
only for services defined via the Gateway.</p>

</td>
</tr>
<tr id="VirtualService-gateways">
<td><code>gateways</code></td>
<td><code>string[]</code></td>
<td>
<p>The names of gateways and sidecars that should apply these routes. A
single VirtualService is used for sidecars inside the mesh as well as
for one or more gateways. The selection condition imposed by this
field can be overridden using the source field in the match conditions
of protocol-specific routes. The reserved word <code>mesh</code> is used to imply
all the sidecars in the mesh. When this field is omitted, the default
gateway (<code>mesh</code>) will be used, which would apply the rule to all
sidecars in the mesh. If a list of gateway names is provided, the
rules will apply only to the gateways. To apply the rules to both
gateways and sidecars, specify <code>mesh</code> as one of the gateway names.</p>

</td>
</tr>
<tr id="VirtualService-http">
<td><code>http</code></td>
<td><code><a href="#HTTPRoute">HTTPRoute[]</a></code></td>
<td>
<p>An ordered list of route rules for HTTP traffic. HTTP routes will be
applied to platform service ports named &lsquo;http-<em>&rsquo;/&lsquo;http2-</em>&rsquo;/&lsquo;grpc-*&rsquo;, gateway
ports with protocol HTTP/HTTP2/GRPC/ TLS-terminated-HTTPS and service
entry ports using HTTP/HTTP2/GRPC protocols.  The first rule matching
an incoming request is used.</p>

</td>
</tr>
<tr id="VirtualService-tls">
<td><code>tls</code></td>
<td><code><a href="#TLSRoute">TLSRoute[]</a></code></td>
<td>
<p>An ordered list of route rule for non-terminated TLS &amp; HTTPS
traffic. Routing is typically performed using the SNI value presented
by the ClientHello message. TLS routes will be applied to platform
service ports named &lsquo;https-<em>&rsquo;, &lsquo;tls-</em>&rsquo;, unterminated gateway ports using
HTTPS/TLS protocols (i.e. with &ldquo;passthrough&rdquo; TLS mode) and service
entry ports using HTTPS/TLS protocols.  The first rule matching an
incoming request is used.  NOTE: Traffic &lsquo;https-<em>&rsquo; or &lsquo;tls-</em>&rsquo; ports
without associated virtual service will be treated as opaque TCP
traffic.</p>

</td>
</tr>
<tr id="VirtualService-tcp">
<td><code>tcp</code></td>
<td><code><a href="#TCPRoute">TCPRoute[]</a></code></td>
<td>
<p>An ordered list of route rules for opaque TCP traffic. TCP routes will
be applied to any port that is not a HTTP or TLS port. The first rule
matching an incoming request is used.</p>

</td>
</tr>
<tr id="VirtualService-export_to">
<td><code>exportTo</code></td>
<td><code>string[]</code></td>
<td>
<p>A list of namespaces to which this virtual service is exported. Exporting a
virtual service allows it to be used by sidecars and gateways defined in
other namespaces. This feature provides a mechanism for service owners
and mesh administrators to control the visibility of virtual services
across namespace boundaries.</p>

<p>If no namespaces are specified then the virtual service is exported to all
namespaces by default.</p>

<p>The value &ldquo;.&rdquo; is reserved and defines an export to the same namespace that
the virtual service is declared in. Similarly the value &ldquo;*&rdquo; is reserved and
defines an export to all namespaces.</p>

<p>NOTE: in the current release, the <code>exportTo</code> value is restricted to
&ldquo;.&rdquo; or &ldquo;*&rdquo; (i.e., the current namespace or all namespaces).</p>

</td>
</tr>
</tbody>
</table>
</section>