docs: add v2beta1 description (#602)
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+---
+title: ApisixRoute/v2beta1 Reference
+---
+
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+
+## Spec
+
+Meaning of each field in the spec of ApisixRoute are followed, the top level fields (`apiVersion`, `kind` and `metadata`) are same as other Kubernetes Resources.
+
+| Field | Type | Description |
+|---------------|----------|----------------------------------------------------|
+| http | array | ApisixRoute's HTTP route rules. |
+| http[].name | string (required) | The route rule name. |
+| http[].priority | integer | The route priority, it's used to determine which route will be hitted when multile routes contains the same URI. Large number means higher priority. |
+| http[].match | object | Route match conditions. |
+| http[].match.paths | array | A series of URI that should be matched (oneof) to use this route rule. |
+| http[].match.hosts | array | A series of hosts that should be matched (oneof) to use this route rule.
+| http[].match.methods | array | A series of HTTP methods(`GET`, `POST`, `PUT`, `DELETE`, `PATCH`, `HEAD`, `OPTIONS`, `CONNECT`, `TRACE`) that should be matched (oneof) to use this route rule.
+| http[].match.remoteAddrs | array | A series of IP address (CIDR format) that should be matched (oneof) to use this route rule.
+| http[].match.exprs | array | A series expressions that the results should be matched (oneof) to use this route rule.
+| http[].match.exprs[].subject | object | Expression subject.
+| http[].match.exprs[].subject.scope | string | Specify where to find the subject, values can be `Header`, `Query`, `Cookie` and `Path`.
+| http[].match.exprs[].subject.name | string | Specify subject name, when scope is `Path`, this field can be absent.
+| http[].match.exprs[].op | string | Expression operator, see [Expression Operators](#expression-operators) for the detail of enumerations.
+| http[].match.exprs[].value | string | Expected expression result, it's exclusive with `http[].match.exprs[].set`.
+| http[].match.exprs[].set | array | Expected expression result set, only used when the operator is `In` or `NotIn`, it's exclusive with `http[].match.exprs[].value`.
+| http[].backend | object | The backend service. Deprecated: use http[].backends instead.
+| http[].backend.serviceName | string | The backend service name, note the service and ApisixRoute should be created in the same namespace. Cross namespace referencing is not allowed.
+| http[].backend.servicePort | integer or string | The backend service port, can be the port number or the name defined in the service object.
+| http[].backend.resolveGranularity | string | See [Service Resolve Granularity](#service-resolve-granularity) for the details.
+| http[].backends | object | The backend services. When the number of backends more than one, weight based traffic split policy will be applied to shifting traffic between these backends.
+| http[].backends[].serviceName | string | The backend service name, note the service and ApisixRoute should be created in the same namespace. Cross namespace referencing is not allowed.
+| http[].backends[].servicePort | integer or string | The backend service port, can be the port number or the name defined in the service object.
+| http[].backends[].resolveGranularity | string | See [Service Resolve Granularity](#service-resolve-granularity) for the details.
+| http[].backends[].weight | int | The backend weight, which is critical when shifting traffic between multiple backends, default is `100`. Weight is ignored when there is only one backend.
+| http[].plugins | array | A series of APISIX plugins that will be executed once this route rule is matched |
+| http[].plugins[].name | string | The plugin name, see [docs](http://apisix.apache.org/docs/apisix/getting-started) for learning the available plugins.
+| http[].plugins[].enable | boolean | Whether the plugin is in use |
+| http[].plugins[].config | object | The plugin configuration, fields should be same as in APISIX. |
+| http[].websocket | boolean | Whether enable websocket proxy. |
+| stream | array | ApisixRoutes' stream route rules, which contains TCP or UDP rules.|
+| stream[].protocol | string (required) | The protocol of rule. Support `TCP` or `UDP`|
+| stream[].name | string (required) | The Route rule name. |
+| stream[].match | object (required) | The Route match conditions. |
+| stream[].match.ingressPort | integer (required) | the Ingress proxy server listening port, note since APISIX doesn't support dynamic listening, this port should be defined in [apisix configuration](https://github.com/apache/apisix/blob/master/conf/config-default.yaml#L101).|
+| stream[].backend | object | The backend service. Deprecated: use http[].backends instead.
+| stream[].backend.serviceName | string | The backend service name, note the service and ApisixRoute should be created in the same namespace. Cross namespace referencing is not allowed.
+| stream[].backend.servicePort | integer or string | The backend service port, can be the port number or the name defined in the service object.
+| stream[].backend.resolveGranularity | string | See [Service Resolve Granularity](#service-resolve-granularity) for the details.
+
+## Expression Operators
+
+| Operator | Meaning |
+|----------|---------|
+| Equal| The result of `subject` should be equal to the `value` |
+| NotEqual | The result of `subject` should not be equal to `value` |
+| GreaterThan | The result of `subject` should be a number and it must larger then `value`. |
+| LessThan | The result of `subject` should be a number and it must less than `value`. |
+| In | The result of `subject` should be inside the `set`. |
+| NotIn | The result of `subject` should not be inside the `set`. |
+| RegexMatch | The result of `subject` should be matched by the `value` (a PCRE regex pattern). |
+| RegexNotMatch | The result of `subject` should not be matched by the `value` (a PCRE regex pattern). |
+| RegexMatchCaseInsensitive | Similar with `RegexMatch` but the match process is case insensitive |
+| RegexNotMatchCaseInsensitive | Similar with `RegexNotMatchCaseInsensitive` but the match process is case insensitive. |
+
+## Service Resolve Granularity
+
+The service resolve granularity determines whether the [Serivce ClusterIP](https://kubernetes.io/docs/concepts/services-networking/service/#publishing-services-service-types) or its endpoints should be filled in the target upstream of APISIX.
+
+| Granularity | Meaning |
+| ----------- | ------- |
+| endpoint | Filled upstream nodes by Pods' IP.
+| service | Filled upstream nodes by Service ClusterIP, in such a case, loadbalacing are implemented by [kube-proxy](https://kubernetes.io/docs/concepts/overview/components/#kube-proxy).|
