I have 3 search head cluster nodes in my test env. I won't go into details on how I broke the SH cluster. I would like to know how to reinitialize the nodes and re-establishing the SH cluster again. Thanks in advance for your advice.
You can perform following steps to re-initialize the Search head Cluster.
1) Stop the Splunk Service for all Search Head Cluster Nodes.
2) Clear _raft folder from each SH Cluster ($SPLUNK_HOME/ var/run/splunk/_raft)
3) Start Splunk Service
4) Re-Initialize the Search Head Cluster Member using command below. Command provided in Splunk Documentation
5) Bootstrap SH Cluster Members - Command provided in Splunk Documentation
It would be better if we knew why you think you broke it. perhaps.