Add document for etcd state store

Signed-off-by: taenyang <taenyang@outlook.com>

daprdocs/content/en/reference/components-reference/supported-state-stores/setup-etcd.md

@@ -0,0 +1,86 @@
+---
+type: docs
+title: "Etcd"
+linkTitle: "Etcd"
+description: Detailed information on the Etcd state store component
+aliases:
+- "/operations/components/setup-state-store/supported-state-stores/setup-etcd/"
+---
+
+## Component format
+
+To setup Etcd state store create a component of type `state.etcd`. See [this guide]({{< ref "howto-get-save-state.md#step-1-setup-a-state-store" >}}) on how to create and apply a state store configuration.
+
+
+```yaml
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: <NAME>
+spec:
+  type: state.etcd
+  version: v1
+  metadata:
+  - name: endpoints
+    value: <CONNECTION STRING> # Required. Example: 192.168.0.1:2379,192.168.0.2:2379,192.168.0.3:2379
+  - name: keyPrefixPath
+    value: <KEY PREFIX STRING> # Optional. default: "". Example: "dapr"
+  - name: tlsEnable
+    value: <ENABLE TLS> # Optional. Example: "false"
+  - name: ca
+    value: <CA> # Optional.
+  - name: cert
+    value: <CERT> # Optional.
+  - name: key
+    value: <KEY> # Optional.
+```
+
+{{% alert title="Warning" color="warning" %}}
+The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described [here]({{< ref component-secrets.md >}}).
+{{% /alert %}}
+
+## Spec metadata fields
+
+| Field              | Required | Details | Example |
+|--------------------|:--------:|---------|---------|
+| endpoints          | Y        | Connection string to Etcd server | `"192.168.0.1:2379,192.168.0.2:2379,192.168.0.3:2379"`
+| keyPrefixPath      | N        | Key prefix path in Etcd. Default is `""` | `"dapr"`
+| tlsEnable          | N        | Whether to enable tls  | `"false"`
+| ca                 | N        | Contents of Etcd server CA file | `"ca value"`
+| cert               | N        | Contents of Etcd server certificate file | `"cert value"`
+| key                | N        | Contents of Etcd server key file | `"key value"`
+
+## Setup Etcd
+
+{{< tabs "Self-Hosted" "Kubernetes" >}}
+
+{{% codetab %}}
+
+You can run Etcd locally using Docker Compose:
+```
+version: '2'
+services:
+  etcd:
+    image: gcr.io/etcd-development/etcd:v3.4.20
+    ports:
+      - "12379:2379"
+    command: etcd --listen-client-urls http://0.0.0.0:2379 --advertise-client-urls http://0.0.0.0:2379```
+```
+You can then interact with the server using `localhost:12379`.
+
+{{% /codetab %}}
+
+{{% codetab %}}
+
+We can use [Helm](https://helm.sh/) to quickly create an Etcd instance in our Kubernetes cluster. This approach requires [Installing Helm](https://github.com/helm/helm#install).
+
+Follow the instructions [here](https://github.com/bitnami/charts/tree/main/bitnami/etcd) to get started with setting up Etcd in Kubernetes.
+
+{{% /codetab %}}
+
+{{< /tabs >}}
+
+## Related links
+- [Basic schema for a Dapr component]({{< ref component-schema >}})
+- Read [this guide]({{< ref "howto-get-save-state.md#step-2-save-and-retrieve-a-single-state" >}}) for instructions on configuring state store components
+- [State management building block]({{< ref state-management >}})