"Change the DHCP scope options," she muttered, logging into the corporate DHCP server. Option 150, the Cisco magic. She replaced the dead physical server's IP with the new virtual Publisher's IP.
CUCM's virtualized heartbeat timers are notoriously sensitive. In a physical world, a 200ms delay is a shrug. In a hypervisor, if the ESXi host gets busy, that same delay can trigger a "node isolation" event. The cluster would split-brain faster than you could say "call manager group." cucm virtualization
She launched the Cisco-provided OVA template for CUCM 12.5. Four vCPUs. 8GB RAM. 110GB thick-provisioned eager-zeroed disk. The UCS blades hummed as the VM materialized on shared storage. No local disk failures. No proprietary hardware dependencies. Just pure, clean compute. "Change the DHCP scope options," she muttered, logging