Hi Andy,
Could VMs run with both sets of IPs?
ie:
Step 1: give new ips to customers
Step 2: customer adds new ip(s) as a extra virtual interfaces
Step 3: customer checks service works okay on new ips, updates their
dns, requests bitfolk backup/nagios change to new ips
Step 4: sometime later customer remove the old ips, and hopefully
nothing breaks (but if it does they can temporarily add old ips back
whilst they fix it)
Step 5: sometime later bitfolk remove routing to the old ips
Cheers,
Joseph