Changing Specifications

Prerequisites

• The target cluster is available and has no tasks in progress.
• The target cluster has sufficient quotas available.
• When changing the node specifications, ensure that all service data has replicas so the services will not be interrupted.

  Run the GET _cat/indices?v command in Kibana. If the returned rep value is greater than 0, the data has replicas. If the returned rep value is 0, the data has no replicas. In this case, create snapshots for the cluster by referring to Manually Creating a Snapshot.

• If the data volume is large, it may take long to modify the node specifications. You are advised to modify specifications during off-peak hours.

Constraints

• The number of nodes and the capacity of node storage cannot be changed. You can add nodes and increase the node storage capacity by referring to Scaling Out a Cluster. For details about how to reduce the number of nodes, see Scaling in a Cluster.
• After decreasing cluster specifications, the cluster performance will deteriorate and service capabilities will be affected. Exercise caution when performing this operation.
• If a cluster has multiple node types, you can change the specifications of only one type at a time. After the change, nodes in other types still maintain their original specifications.
• Kibana is unavailable during specification change.
• During the specification modification, the nodes are stopped and restarted in sequence. It is a rolling process.

Procedure

1. Log in to the CSS management console.
2. In the navigation pane, choose a cluster type. The cluster management page is displayed.
3. Choose More > Modify Configuration in the Operation column of the target cluster. The Modify Configuration page is displayed.
4. On the Modify Configuration page, choose the Scale Cluster tab and click Change Specifications to set parameters.
   • Action: select Change specifications.
   • Resources: The changed amount of resources.
   • Nodes: Specifications of the default data nodes. Select the required specifications from the Node Specifications drop-down list and select the node that you want to change the specifications.
   • If a cluster has master nodes, client nodes, or cold data nodes, you can change their specifications.
5. Click Next.
6. Confirm the information and click Submit.
7. In the displayed Verify Index Copy dialog box, select Verify index copies if you need. Click OK.
   • Check items for node specifications change: Verify index copies and Cluster status check.

     Table 1 Check item description

     Check Item	Description
     Verify index copies	By default, CSS checks for indexes that do not have any replicas created for them. You can skip this step, but the lack of index replicas may impact service availability during a cluster specifications change. If you select Verify index copies and the cluster has no master node, each index is required to have at least one replica and the cluster must have at least three nodes. If you select Verify index copies and the cluster has a master node, each index is required to have at least one replica, but there is no requirement on how many nodes the cluster must have.
     Cluster status check	By default, the cluster status is checked before specifications change. The specifications of nodes are changed one by one to ensure service availability and data security. If a cluster is overloaded and services are faulty, the request for a specifications change may fail to be delivered. In this case, you can skip cluster status check, but doing so may cause the cluster to become faulty and services become interrupted. Exercise caution when performing this operation.

8. Click Back to Cluster List to switch to the Clusters page. The Cluster Status is Configuration modified. When Cluster Status changes to Available, the cluster specifications have been successfully modified.