Feat: add docs for ref-url (#901)

Signed-off-by: Yin Da <yd219913@alibaba-inc.com>

docs/end-user/components/ref-objects.md

@@ -10,9 +10,12 @@ You can reference and distribute existing Kubernetes objects with KubeVela in th
 - Promote deployments from canary clusters into production clusters.
 - Using Kubernetes apiserver as the control plane and storing all Kubernetes objects data in external databases. Then dispatch those data into real Kuberenetes managed clusters.
 
+Besides, you can also refer to Kubernetes objects from remote URL links.
 
 ## Refer to Existing Kubernetes Objects in Component
 
+### Refer to objects in cluster
+
 To use existing Kubernetes objects in the component, you need to use the `ref-objects` typed component and declare which resources you want to refer to. For example, in the following example, the secret `image-credential-to-copy` in namespace `examples` will be taken as the source object for the component. Then you can use the topology policy to dispatch it into hangzhou clusters.
 
 ```yaml
@@ -37,6 +40,24 @@ spec:
           region: hangzhou
 ```
 
+### Refer to objects from URL
+
+If your source Kubernetes objects are from remote URLs, you can also refer to them in the component properties as follows. Your remote URL files could include multiple-resources as well.
+
+```yaml
+apiVersion: core.oam.dev/v1beta1
+kind: Application
+metadata:
+  name: example-app
+  namespace: default
+spec:
+  components:
+  - name: busybox
+    type: ref-objects
+    properties:
+      urls: ["https://gist.githubusercontent.com/Somefive/b189219a9222eaa70b8908cf4379402b/raw/e603987b3e0989e01e50f69ebb1e8bb436461326/example-busybox-deployment.yaml"]
+```
+
 ## Details for the *ref-objects* typed component
 
 The most simple way to specify resources is to directly use `resource: secret` or `resource: deployment` to describe the kind of resources. If no `name` or `labelSelector` is set, the application will try to find the resource with the same name as the component name in the application's namespace. You can also explicitly specify `name` and `namespace` for the target resource as well.

docs/tutorials/k8s-object.mdx

@@ -132,8 +132,8 @@ You can also check the deployment and service with the `kubectl` or any other to
 vela workflow resume app-with-k8s-objects
 ```
 
-The delivery process can be powerful if you're [distributing resources across multi-clusters](../end-user/components/ref-objects). 
-
+KubeVela also allows referring Kubernetes objects from Kubernetes cluster or remote URL links, so that you do not need to write Kubernetes objects inside Application directly.
+Read more about it in [ref-objects](../end-user/components/ref-objects).
 
 ## Deploy with UI Console
 

versioned_docs/version-v1.5/end-user/components/ref-objects.md

@@ -10,9 +10,12 @@ You can reference and distribute existing Kubernetes objects with KubeVela in th
 - Promote deployments from canary clusters into production clusters.
 - Using Kubernetes apiserver as the control plane and storing all Kubernetes objects data in external databases. Then dispatch those data into real Kuberenetes managed clusters.
 
+Besides, you can also refer to Kubernetes objects from remote URL links.
 
 ## Refer to Existing Kubernetes Objects in Component
 
+### Refer to objects in cluster
+
 To use existing Kubernetes objects in the component, you need to use the `ref-objects` typed component and declare which resources you want to refer to. For example, in the following example, the secret `image-credential-to-copy` in namespace `examples` will be taken as the source object for the component. Then you can use the topology policy to dispatch it into hangzhou clusters.
 
 ```yaml
@@ -37,6 +40,24 @@ spec:
           region: hangzhou
 ```
 
+### Refer to objects from URL
+
+If your source Kubernetes objects are from remote URLs, you can also refer to them in the component properties as follows. Your remote URL files could include multiple-resources as well.
+
+```yaml
+apiVersion: core.oam.dev/v1beta1
+kind: Application
+metadata:
+  name: example-app
+  namespace: default
+spec:
+  components:
+  - name: busybox
+    type: ref-objects
+    properties:
+      urls: ["https://gist.githubusercontent.com/Somefive/b189219a9222eaa70b8908cf4379402b/raw/e603987b3e0989e01e50f69ebb1e8bb436461326/example-busybox-deployment.yaml"]
+```
+
 ## Details for the *ref-objects* typed component
 
 The most simple way to specify resources is to directly use `resource: secret` or `resource: deployment` to describe the kind of resources. If no `name` or `labelSelector` is set, the application will try to find the resource with the same name as the component name in the application's namespace. You can also explicitly specify `name` and `namespace` for the target resource as well.

versioned_docs/version-v1.5/tutorials/k8s-object.mdx

@@ -132,8 +132,8 @@ You can also check the deployment and service with the `kubectl` or any other to
 vela workflow resume app-with-k8s-objects
 ```
 
-The delivery process can be powerful if you're [distributing resources across multi-clusters](../end-user/components/ref-objects). 
-
+KubeVela also allows referring Kubernetes objects from Kubernetes cluster or remote URL links, so that you do not need to write Kubernetes objects inside Application directly.
+Read more about it in [ref-objects](../end-user/components/ref-objects).
 
 ## Deploy with UI Console