About the Control Plane group
A Control Plane is a group of cluster control nodes. They host the ETCD database and some critical services. For test clusters, as a rule, 1 node in a group is enough, for fault-tolerant clusters - 3. We do not recommend creating more than 3 nodes, because this can cause the cluster to slow down due to the complex ETCD quorum mechanism on the nodes. Only one Control Plane group can be created in a cluster.
Information about the node group/its status can be monitored on the “Manage Nodes” page of the cluster being viewed, as well as in the management cluster in the Administration/Custom Resources section using the MachineDeployment custom resource in the cluster.x-k8s.io API group.
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On the Manage Nodes page you can change the configuration of the Control Plane group. To do this, to the right of the name of the group of Control Plane nodes, click on the “Group Configuration” button. The configuration includes: the number of nodes, parameters for joining a node to a group, sizing of nodes and the self-healing mechanism. Managing the number of nodes in a group is available on the ClusterAPI Configuration tab.
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The following tabs are available on the page that opens: