By default all VPX instances hosted on the SDX platform are configured to auto start. During a SDX migration project it was useful to prevent this behavior in the event that the SDX platform rebooted. The primary reason for this was because I used the same IP addresses on the new instances that the old instances had and did not want to cause an IP conflict by ARPing over the new instance if the SDX platform rebooted.
SSH to the underlying XenServer host on your SDX appliance
Discover the VM UUIDs by executing the following command
Note: this command will list all of the VMs on the appliance
Copy the UUID string from the VM you want to prevent from auto-starting
Execute the following command to set auto_poweron to false for that VM
xe vm-param-set uuid=yourUUID other-config:auto_poweron=false
Note: yourUUID will be populated with the UUID you copied in step 3
Verify the parameter was modified by executing
xe vm-list uuid=yourUUID params=other-config
The selected VPX instance defined by UUID will no longer auto-start if the SDX platform is rebooted.