a little bit of background Information before asking the question: Our current setup is:
- 1 Master bind and 1 Slave bind in Datacenter A
- 2 Slave binds in Datacenter B
- 2 Unbounds in Datacenter A
- 2 Unbounds in Datacenter B
All managed by Puppet. No dynamic Zones.
Today our management decided to test an emergency shutdown of Datacenter A next Week. Therefore, I need to verify the functionality of our DNS System, since everything is bound to it and will crash if it isn't reachable anymore.
So far I've managed to test wheter or not the DNS resolving still works even if the Master is down for a few days and the result was pleasing (it worked perfectly fine). Therefore, the overall functionality is still given, even if Datacenter A is going down. Nevertheless, I do have concerns about AdHoc changes of some CNAMES or Records during this shutdown (which is quite likely, since some of our backupsystems need a CNAME swap to work). So far, I've seen that you can't change things on a Slave (which was my first hope, cause we wouldn't need to change a thing then). At least it didn't work me.
Therefore, my thoughts are, that we need another master. But I wasn't able to find anything on the web whether or not those thoughts actually work.
Coming to the question(s):
1.: Is it possible to change one of the Slave Servers in Datacenter B to be a second Master? Therefore, having 1 Master and 1 Slave in each Datacenter. What are common problems that can occur in such a setup?
2.: Is it possible to run a Master-only setup? Therefore having 2 Masters in each Datacenter and not a single slave. What are common problems that can occur in such a setup?
3.: Is there any other way to solve this Issue? Is there any best-pracitce example?