Add blog for v0.8.0 (#277)

Signed-off-by: Benjamin Huo <benjamin@kubesphere.io>

Signed-off-by: Benjamin Huo <benjamin@kubesphere.io>

Author: benjaminhuo

content/en/blog/releases/release_v0.8.0.md

@@ -0,0 +1,73 @@
+---
+title: "Announcing OpenFunction 0.8.0: Speed up function launching with Dapr Proxy"
+linkTitle: "Release v0.8.0"
+date: 2022-10-28
+weight: 93
+
+---
+
+One of the unique features of OpenFunction is its simple integration with various backend services (BaaS) through [Dapr](https://docs.dapr.io/concepts/components-concept/). Currently, OpenFunction supports Dapr [pub/sub](https://docs.dapr.io/reference/components-reference/supported-pubsub/) and [bindings](https://docs.dapr.io/reference/components-reference/supported-bindings/) building blocks, and more will be added in the future.
+
+In OpenFunction v0.7.0 and versions prior to v0.7.0, OpenFunction integrates with BaaS by injecting a dapr sidecar container into each function instance's pod, which leads to the following problems：
+
+- The entire function instance's launch time is slowed down by the launching of the dapr sidecar container.
+- The dapr sidecar container may consume more resources than the function container itself.
+
+To address the problems above, OpenFunction introduces the `Dapr Standalone Mode` in v0.8.0.
+
+## Dapr Standalone Mode
+
+In Dapr standalone mode, one `Dapr Proxy service` will be created for each function which is then shared by all instances of this function. This way, there is no need to launch a seperate Dapr sidecar container for each function instance anymore which reduces the function launching time significantly.
+
+<div align=center><img width="100%" height="100%" src=/images/docs/en/concepts/function/dapr_proxy.png/></div>
+
+## Choose the appropriate Dapr Service Mode
+
+So now you've 2 options to integrate with BaaS:
+
+- `Dapr Sidecar Mode`
+- `Dapr Standalone Mode`
+
+You can choose the appropriate Dapr Service Mode for your functions. The `Dapr Standalone Mode` is the recommened and default mode. You can use `Dapr Sidecar Mode` if your function doesn't scale frequently or you've difficulty to use the `Dapr Standalone Mode`.
+
+You can control how to integrate with BaaS with 2 flags, both can be set in function's `spec.serving.annotations`:
+
+- `openfunction.io/enable-dapr` can be set to `true` or `false`
+- `openfunction.io/dapr-service-mode` can be set to `standalone` or `sidecar`
+- When `openfunction.io/enable-dapr` is set to `true`, users can choose the `Dapr Service Mode` by setting `openfunction.io/dapr-service-mode` to `standalone` or `sidecar`.
+- When `openfunction.io/enable-dapr` is set to `false`, the value of `openfunction.io/dapr-service-mode` will be ignored and neither `Dapr Sidecar` nor `Dapr Proxy Service` will be launched. 
+
+There're default values for both of these two flags if they're not set.
+
+- The value of `openfunction.io/enable-dapr` will be set to `true` if it's not defined  in `spec.serving.annotations` and the function definition contains either `spec.serving.inputs` or `spec.serving.outputs`. Otherwise it will be set to `false`.
+- The default value of `openfunction.io/dapr-service-mode` is `standalone` if not set.
+
+Below you can find a function example to set these two flags:
+
+```yaml
+apiVersion: core.openfunction.io/v1beta1
+kind: Function
+metadata:
+  name: cron-input-kafka-output
+spec:
+  ...
+  serving:
+    annotations:
+      openfunction.io/enable-dapr: "true"
+      openfunction.io/dapr-service-mode: "standalone"
+    template:
+      containers:
+        - name: function # DO NOT change this
+          imagePullPolicy: IfNotPresent 
+    runtime: "async"
+    inputs:
+      - name: cron
+        component: cron
+    outputs:
+      - name: sample
+        component: kafka-server
+        operation: "create"
+    ...
+```
+
+[Here](https://github.com/OpenFunction/OpenFunction/releases/tag/v0.8.0) you can find more information about OpenFunction v0.8.0.