Update 9.upgrade-nebula-cluster.md

docs-2.0/nebula-operator/9.upgrade-nebula-cluster.md

@@ -7,7 +7,7 @@ This topic introduces how to upgrade a Nebula Graph cluster created with Nebula
 
 - Only Nebula Graph clusters created with Nebula Operator are supported.
 
-- Only Nebula Graph versions 2.5.x to 2.6.x are supported for upgrade.
+- Only upgrading Nebula Graph from 2.5.x to 2.6.x is supported.
 
 - Upgrading clusters created via Nebula Operator of version 0.8.0 is not supported.
 
@@ -121,7 +121,7 @@ The version of the Nebula Graph cluster to be upgraded in this topic is `2.5.1`,
   kubectl apply -f apps_v1alpha1_nebulacluster.yaml
   ```
 
-4. After waiting for about 2 minutes, run the following command to see the image versions of the services in the cluster have been changed to {{nebula.branch}}.
+4. After waiting for about 2 minutes, run the following command to see if the image versions of the services in the cluster have been changed to {{nebula.branch}}.
 
   ```bash
   kubectl get pods -l app.kubernetes.io/cluster=nebula  -o jsonpath="{.items[*].spec.containers[*].image}" |tr -s '[[:space:]]' '\n' |sort |uniq -c
@@ -143,7 +143,7 @@ You have created a Nebula Graph cluster with Helm. For details, see [Create a Ne
 
 ### Steps
 
-1. Update information of available charts locally from chart repositories.
+1. Update the information of available charts locally from chart repositories.
 
   ```bash
   helm repo update
@@ -169,7 +169,7 @@ You have created a Nebula Graph cluster with Helm. For details, see [Create a Ne
 
   The value of `--set nebula.version` specifies the version of the cluster you want to upgrade to.
 
-4. After waiting for a while, run the following command to check the status and version of the upgraded cluster.
+4. Run the following command to check the status and version of the upgraded cluster.
 
   Check cluster status: