When you research server clustering, you frequently hear the terms failover and failback. Failover refers to the failure of the active service provider node and passive node's taking over of its responsibilities. At that point, the server that was the passive node becomes the active node. It services clients and handles the cluster's duties. Once the original active node returns to service, you may set it to act as the new passive node, or you may shift the services back to it, causing it to take back its active node role and relegating the formerly passive server to its original role. The term failback refers to the service returning to the original active node.

Requiring a boot password upon execution of the boot loader will prevent an unauthorized user from entering boot parameters or changing the boot partition. This prevents users from weakening security (e.g. turning off SELinux at boot time).
What is a UEFI password?
A UEFI, or BIOS, password is a password that must be entered when the machine is powered on or rebooted in order to continue. Without the password the machine cannot be booted at all - even from external media - and no configuration changes to the UEFI or BIOS settings can be made.
https://www.tenable.com/audits/items/CIS_Red_Hat_EL7_STIG_v2.0.0_STIG.audit:1ee8630516d a75be0fabf64c11ab70c6
https://askleo.com/how_do_i_remove_a_bios_password/#

Tabletop/Simulated failover - the disaster recovery procedures are implemented on a limited scale. Participants engage in role-playing to ensure comprehension and realism.
Parallel recovery using a non-production test environment - the disaster recovery procedures are implemented in a non-production environment. VMs work especially well for this kind of test. The production environment remains unaffected.