Common features and scenarios for Alibaba Cloud Elasticsearch cluster modifications-Elasticsearch(ES)-阿里云帮助中心

Alibaba Cloud Elasticsearch provides several features for modifying your cluster, such as restarting instances or nodes, upgrading or downgrading instances, upgrading versions, deploying multi-zone instances, migrating nodes between zones, and using the high-availability (HA) write feature. After you modify a cluster, you can view the progress of ongoing tasks. This topic describes these features and their common scenarios.

Important

For multi-zone instances, before you make a change, ensure that the number of replicas for any index in the cluster is less than the number of zones. After the change is complete, you can manually increase the number of replicas as needed. For more information, see Index Templates.
Cluster modifications may affect billing. For more information about billing, see Product Billing and Unsubscription Rules.

Feature	Scenario
Restart an instance or node	Alibaba Cloud Elasticsearch provides a feature to restart clusters and nodes. If a cluster becomes abnormal, restart or force restart it based on its health status. For more information, see Restart a cluster or node. Note The service remains available during the restart. However, in some scenarios, such as during high-volume write and query operations, access timeouts may occur. To avoid write errors, perform this operation during off-peak hours.
Upgrade or downgrade an instance	If the cluster configuration does not meet your business needs, upgrade the instance or elastically scale cluster resources to meet your requirements. For more information, see Upgrade a cluster or Elastically scale cluster resources. Note For cluster health and stability, Alibaba Cloud Elasticsearch stopped selling instances with 1-core 2 GB specifications, dedicated master nodes with 2-core 2 GB specifications, and instances of version 7.4 in May 2021. If your purchased specifications are no longer available for sale, first perform the following operations: For the 1-core 2 GB and 2-core 2 GB specifications, upgrade to a stable specification that is available on the purchase page. For information about available specifications on the purchase page, see Parameters on the purchase page. For version 7.4, purchase a version 7.10 instance and then migrate your data. For more information about data migration, see Data migration solution guide. If your business has peak and off-peak hours or other variations that cause node specifications to be higher than required, downgrade the instance, elastically scale cluster resources, or scale in data nodes to reduce costs. For more information, see Downgrade a cluster, Elastically scale cluster resources, or Scale in data nodes of a cluster.
Upgrade version	Alibaba Cloud Elasticsearch supports direct upgrades for some versions. This feature lets you upgrade the instance version or update the kernel patch for a seamless business transition. For more information, see Upgrade the version of a cluster.
Deploy and use a multi-zone instance	Deploying across multiple zones improves the disaster recovery capability of your cluster. If a zone fails, the remaining zones can continue to provide services without interruption. You can also use the console to perform a traffic switchover to fence the failed zone. The system then automatically adds compute resources in the remaining zones to meet your business needs. For more information, see Deploy and use a multi-zone instance.
Migrate nodes in a zone	When you upgrade a cluster, you may find that the inventory for the required specifications is insufficient in a zone. In this case, migrate the data from the nodes in that zone before you upgrade. For more information, see Migrate and upgrade a zone.
Use the high-availability write feature	Use this feature if you have high requirements for cluster stability. This feature implements read/write splitting through an asynchronous high-availability architecture. It ensures cluster stability during high-concurrency writes. For more information, see Use the high-availability write feature.
View instance task progress details	When you modify an instance, you can view information about ongoing tasks in the task list. These tasks include instance creation, restart, and data migration. For more information, see View the progress of an instance task.