Before an SSRM provisioning job can be considered complete it must successfully provision the virtual machine and then discover it. After VM cloning was completed it may experience an unusually high number of discovery failures (message = "CAAP8103 System <system name> discovery failed") before finally successfully discovering the provisioned virtual machine.
Usual reason for these delays were failing name resolutions of the new VM’s host name on the Server Automation system during discovery attempts. Several configuration settings were found to, some times significantly, decrease the amount of time it took to successfully discover these machines. The configuration changes included:
- Disable Client-Side DNS Caching – to disable caching of failed name resolution attempts
- Change the Zone SOA Minimum TTL Default (15 minutes) in DNS Server – to increase rechecks for failed name resolution attempts
- Add preferred DNS server in VM Customization Specification – to support VM host name registration in DNS
It is important to keep in mind that the options listed below may offer faster SSRM discoveries. They are not guaranteed to provide faster SSRM discoveries. Also, any one of these settings may offer improvement. This article is not recommending an all or none approach. Evaluate each of the options below and determine which of them may help. You may find that one, all, or none offer improved discoveries.
Disable Client-Side DNS Caching
These Microsoft KB articles offer guidance for disabling Client-Side DNS Caching
Change the Zone SOA Minimum TTL Default (15 Minutes) in DNS Server
The Microsoft KB article below offers guidance for modifying TTL on Domain Name System Records
Add preferred DNS server in VM Customization Specifications
Within your VMware Customization Specification you can find DNS Server settings by navigating to the Network settings. Once there open the details for the NIC that you want Server Automation to discover the system with. The "Network Properties" dialog open now will give you the option to specify a preferred DNS Server. Set the preferred DNS server here if desired.