Seamless live data center transition?

HI all,

I need to move a few dozen FreePBXen with some commercial modules running in individual VMs to a new data center.

I’m trying to work out a plan to move the PBXes to the new data center in a way that will be transparent to the endpoints, or at the very least cause minimal downtime.

Some of the installations are rather old, and there’s a handful of peculiarities on each, so the typical backup/restore process hasn’t gone smoothly, at least in our tests.

My current approach is to put a clone the VMs in the new data center and use something like Kamailio to route the SIP traffic to the new servers/IPs. I’ve never used it before, so I may be barking up the wrong tree, but it appears to do what I’m suggesting.

If so, I’m thinking I can install Kamailio on each VM, point it to the local asterisk/FreePBX initially, clone the VM, then after the new instance is up and running, point the proxy on the original VM to the cloned one, followed by the appropriate DNS changes.

Endpoints are mostly Yealink, and I’m not sure if they’ll feel the need to restart when the registration/SIP server’s IP changes, but a quick bounce when not in use isn’t the end of the world. I’d very much like to avoid having to send an update to each phone manually, but I can script a SIP NOTIFY if required.

Anything stupid, wrong, ignorant, or just smelly about this tactic? Or, for that matter, any other suggestions?

Thanks for the feedback.

Are your phones programmed to point to a DDNS or to specific IP’s? If you are using DDNS, you simply change the IP that the DDNS translates for the phones. I think the whole proxy thing is complicated and will bite you.

Another approach is that if you are using the EPM module, you can make the changes in that and push it out to the phones just before you take the old site down.

The endpoints are provisioned with DNS (not dynamic DNS), which do indeed point to a specific IP - kinda the whole point of DNS :laughing:.

The challenge with simply altering the DNS is there’s no good way of knowing when the phone will pull the new IP. It could be minutes; it could be hours, or even days.

Plus, since not all phones on all servers reside in the same location, it’s possible some would be updated before others. It all really depends on the upstream provider’s DNS cache policy. These days, most providers don’t cache for a long period, but I’ve seen it take more than 24 hours.

Of course, we will be changing the DNS, but the proxy allows us to buffer that change, and point all originations and terminations to the new server, until all endpoints are updated.

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