How to replicate data from 1 VM into another VM on-prem with linux/ubunto server

Question

VM = Application on Ruby on rails using docker, memory = m5 16xlarge, 256, 1tb

Both VM(Primary & Backup) will be deploy on on-prem.

I have requirement where i need to sync both VM's simultaneously to get the latest data in both, if in case of failover user can access to VM2 using load balancer.

how can i replicate data from Primary VM to Backup VM

Thanks in advance.