Fix docs of gcs offload (apache#6943)

wolfstudy · web-flow · commit 73172ce1695a · 2020-05-12T14:08:17.000+08:00
* Fix docs of gcs offload

Signed-off-by: xiaolong.ran &lt;rxl@apache.org&gt;

* fix comments

Signed-off-by: xiaolong.ran &lt;rxl@apache.org&gt;
diff --git a/site2/docs/cookbooks-tiered-storage.md b/site2/docs/cookbooks-tiered-storage.md
@@ -168,12 +168,15 @@ a Json file, containing the GCS credentials of a service account.
 more information of how to create this key file for authentication. More information about google cloud IAM
 is available [here](https://cloud.google.com/storage/docs/access-control/iam).
 
-Usually these are the steps to create the authentication file:
-1. Open the API Console Credentials page.
-2. If it's not already selected, select the project that you're creating credentials for.
-3. To set up a new service account, click New credentials and then select Service account key.
-4. Choose the service account to use for the key.
-5. Download the service account's public/private key as a JSON file that can be loaded by a Google API client library.
+To generate service account credentials or view the public credentials that you've already generated, follow the following steps:
+
+1. Open the [Service accounts page](https://console.developers.google.com/iam-admin/serviceaccounts).
+2. Select a project or create a new one.
+3. Click **Create service account**.
+4. In the **Create service account** window, type a name for the service account, and select **Furnish a new private key**. If you want to [grant G Suite domain-wide authority](https://developers.google.com/identity/protocols/OAuth2ServiceAccount#delegatingauthority) to the service account, also select **Enable G Suite Domain-wide Delegation**.
+5. Click **Create**.
+
+> Notes: Make ensure that the service account you create has permission to operate GCS, you need to assign **Storage Admin** permission to your service account in [here](https://cloud.google.com/storage/docs/access-control/iam).
 
 ```conf
 gcsManagedLedgerOffloadServiceAccountKeyFile="/Users/hello/Downloads/project-804d5e6a6f33.json"
