The node name reuse function enables users to reuse the node names of historical VMs for new VMs. It prevents the rapid increase of differently named nodes, especially when the nodes are identical processes that run over different times. This helps you monitor environments with short-life VMs.

To enable this function, specify the following in the IIB configuration (controller-info.xml) file.

<node-reuse>true</node-reuse>
<node-reuse-prefix>prefixName</node-reuse-prefix>

The node-reuse-prefix property allows the controller to generate node names dynamically using the prefix <prefixName>. The nodes running in parallel are differentiated by suffixes (-1, -2, -3, and so on), depending on the number of nodes running. It generates a node name with App, Tier, and Sequence number when enabled. It also pools the node names. For example, the sequence numbers are reused when the nodes are purged (based on the node lifetime).

Once a node shuts down, it becomes a historical node, and its name can be used as a new node. However, if a node shuts down unexpectedly or forcefully, the agent does not inform the controller about the shutdown. In this case, the node name is not reused. To avoid forceful shutdowns, you can use terminationGracePeriod. IIB agent recommends terminationGracePeriod of 60 seconds.

For more information on terminationGracePeriod, see Kubernetes best practices: terminating with grace.

If you do not specify this function, the IIB agent generates internal node names based on IBM standards.