Cluster restart

A Kingsoft Cloud Elasticsearch Service (KES) cluster can be restarted in rolling or force mode. Choose a proper mode to restart a cluster based on the usage of the cluster.

• Rolling restart: In rolling restart, each node is restarted in phased mode. The restart takes a long time and is secure. Before you perform rolling restart, ensure that the cluster is in the Green service state and the resource utilization is not high. You can view the resource utilization on the Cluster Monitoring page. For example, the CPU usage cannot exceed 80%, the heap memory usage of a node must be about 50%, and node load_1m must be smaller than the number of CPU cores of the current data node.) During the restart of a node, the CPU and memory usage of the node may experience a sharp increase temporarily. Jitter may occur on the services that are run on this node. In most cases, the services will be restored to normal in a period of time.

• Force restart: Force restart is used when the cluster is in the Yellow or Red service state or the cluster has no replica indexes. The force restart operation takes a short time, has high risks, and may lead to data loss. We recommend that you restore a cluster to the Green state before you forcibly restart the cluster. If the cluster status cannot be restored, fully understand the risks of force restart before you perform forcibly restart the cluster.