Alibaba Cloud Elasticsearch allows you to perform the following operations to make changes to a cluster: restart the cluster or a node in the cluster, upgrade or downgrade the configuration of the cluster, upgrade the version of the cluster, and migrate nodes in the cluster across zones. If the cluster is a multi-zone cluster, you can also perform a switchover on faulty nodes in the cluster. After you perform the preceding operations, you can view the progress of the operations in the Elasticsearch console. This topic describes the scenarios in which you can perform the preceding operations.

Notice When you make a change to a multi-zone cluster, make sure that the number of replica shards of each index in the cluster is less than the number of zones in which the cluster is deployed. After the change is complete, you can manually increase the number of replica shards based on your business requirements. For more information about how to change the number of replica shards of indexes in a cluster, see Index Templates.
Operation Use scenario
Restart a cluster or node If your cluster is in an abnormal state, you can restart or forcibly restart the cluster based on its health status. For more information, see Restart a cluster or node.
Upgrade or downgrade the configuration of a cluster
  • If the configuration of your cluster cannot meet your business requirements, you can upgrade the configuration of your cluster. For more information, see Upgrade the configuration of a cluster.
    Note To ensure the health and stability of your cluster, Alibaba Cloud no longer provides data nodes with the specifications of 1 vCPU and 2 GiB of memory, dedicated master nodes with the specifications of 2 vCPUs and 2 GiB of memory, and Elasticsearch V7.4 clusters since May 2021. If your cluster contains the preceding nodes or your cluster is of V7.4, we recommend that you perform the following operations before you upgrade the configuration of your cluster:
    • If your cluster contains the preceding nodes, upgrade the specifications of the nodes to other specifications that are provided on the buy page. For more information about the specifications that are provided on the buy page, see Parameters on the buy page.
    • If your cluster is of V7.4, purchase a V7.10 cluster and migrate data from the original cluster to the V7.10 cluster.
  • If your business has traffic peak and off-peak hours, the node specifications of your cluster may be higher than those required by your business during off-peak hours. In this case, you can downgrade the configuration of your cluster or scale in your cluster to reduce costs. For more information, see Downgrade the configuration of a cluster or Scale in a cluster.
Upgrade the version of a cluster You can perform an in-place upgrade for your cluster version or kernel. In-place upgrades do not affect your business. Only some versions support in-place upgrades. For more information, see Upgrade the version of a cluster.
Perform a switchover on faulty nodes in a cluster Multi-zone clusters offer enhanced disaster recovery capabilities. If your cluster is a multi-zone cluster and the nodes in one zone become faulty, the nodes in the remaining zones can still provide services without interruption. In addition, you can perform a switchover on the faulty nodes in the Elasticsearch console to isolate the faulty nodes. Then, the system adds computing resources to the remaining zones to make up for the resource loss that is caused by the faulty nodes. For more information, see Deploy and use a multi-zone Elasticsearch cluster.
Migrate nodes across zones If you want to upgrade the configuration of your cluster but the zone where the cluster resides does not provide sufficient resources for the upgrade, you can first migrate nodes in the cluster to a different zone. For more information, see Migrate nodes in a zone.
View the progress of a cluster task After you perform an operation to make a change to your cluster, you can click the Tasks icon on the Basic Information page of the cluster in the Elasticsearch console to view the progress of the operation. In the Tasks dialog box, you can view the progress of a running task, such as a cluster creation task, cluster restart task, or data migration task. For more information, see View the progress of a cluster task.