You can have a look at this document , this will help you
You are missing the part (Remove the udev persistent device rules)
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From: Mohd Zainal Abidin Rabani [mailto:zai...@nocser.net]
Sent: Wednesday, 21 September 2016 10:15 AM
Subject: Issue with template
I'm creating template from instance that install using ISO. After finish
install and reboot, I update OS from centos 5.6 to 6.8. Then I reboot again.
After reboot I shutdown the instance and create template from disk. After
creating template finish and available for use I try create new instance from
template that I created. After instance up and running using new template I saw
eth0 not available. It show only eth1. So I need to change in
/etc/sysconfig/network-scripts. Is this normal or I miss any step?