When deploying VMware Cloud Foundation (VCF), proper setup of DNS and NTP services is crucial for success. These fundamental infrastructure components often seem simple, but they’re frequently the source of deployment issues and troubleshooting headaches. Here’s what you need to know before starting your VCF deployment.

The Deployment Parameters Workbook

VCF provides a Deployment Parameters Workbook where you’ll need to specify:

  • DNS server information
  • NTP server details
  • IP addresses for:
    • vCenter Server
    • ESXi hosts
    • SDDC Manager
    • NSX Managers

DNS Requirements

Forward and Reverse Lookups

One of the most common oversights in VCF deployment is incomplete DNS configuration. You must configure:

  • Forward lookup (A records)
  • Reverse lookup (PTR records)
  • All components must have both types of records

DNS Access

Beyond just having the records, ensure that:

  • All machines can access the DNS server
  • Firewall rules allow DNS traffic from the VCF subnet
  • DNS server configuration (like BIND) allows queries from the VCF subnet
  • There are no typos in DNS records

Validation

VCF performs thorough DNS checks during deployment:

  • Validates forward lookups using fully qualified domain names
  • Checks reverse lookups for all IP addresses
  • Ensures DNS resolution works for all components

NTP Configuration

Time Synchronization

Time synchronization is critical for VCF operations:

  • All components must be in sync
  • NTP servers must be up and accessible
  • ESXi hosts must be able to reach NTP servers
  • All management components must synchronize with the same time source

Common NTP Issues

NTP problems can manifest in unexpected ways:

  • Random errors that seem unrelated to timing
  • Authentication failures
  • Certificate validation issues
  • Security service problems
  • Component communication failures

NTP Access

Ensure that:

  • NTP ports are open in firewalls
  • Security policies allow NTP traffic
  • NTP server has sufficient capacity for all clients

Best Practices

  1. Pre-deployment Checklist:

    • Verify all DNS records (forward and reverse) before starting
    • Test NTP synchronization on all networks
    • Confirm firewall rules for both DNS and NTP

  2. IP Address Management:

    • Use static IPs whenever possible
    • Document all IP assignments
    • Reserve IP ranges for VCF use

  3. Validation Steps:

    • Test DNS resolution from multiple points in the network
    • Verify NTP synchronization across all components
    • Document any subnet restrictions or security policies

Common Pitfalls to Avoid

  • Forgetting reverse DNS lookups
  • Overlooking subnet restrictions on DNS servers
  • Assuming NTP is working without verification
  • Not checking firewall rules for both DNS and NTP traffic
  • Typographical errors in DNS records
  • Incomplete DNS propagation before deployment

Conclusion

While DNS and NTP might seem like basic infrastructure components, they’re crucial for a successful VCF deployment. Taking the time to properly configure and verify these services before beginning your deployment can save hours of troubleshooting later. Remember: most VCF deployment issues can be traced back to these fundamental services, so get them right from the start.