I've got 3 ubuntu servers connected with a Tinc VPN right now. 2 servers are running mysql 5.6 db's, and the 3rd is used only as a monitor. We're using mmm to do the monitoring and assign a floating ip to a writer role. (Before someone tells me that I shouldn't be using mmm, I know there are other solutions for HA db replication, however for our purposes an asynchronous solution is actually better than the newer synchronous options, and we've got mmm running on a different application so I'm somewhat familiar with it already, so that's why we chose it for this, and even with its faults, it's better than not having anything).

The problem I'm having is that the floating writer ip never gets routed properly. Here's the output from mmm_control show:

server4( master/ONLINE. Roles: writer(
server5( master/ONLINE. Roles:

So mmm thinks it's got the .201 ip assigned to direct to the .4 server, but when I ping .201, I get this:

From icmp_seq=1 Destination Net Unknown

The basic tinc setup is working - I can ping/ssh/etc between the 3 servers:

64 bytes from icmp_seq=1 ttl=64 time=0.740 ms

The basic mmm setup is working - if I move the writer role to server5, that works too (server4 becomes readonly, server5 is now writable, and the output of mmm_control shows that the .201 writer role is now on server5).

What I don't know is if there's some simple configuration that I've missed (my background is as a programmer, I learn the networking/sysadmin stuff on a need-to-know basis). Or perhaps the way mmm assigns floating ip's is incompatible with the way a tinc vpn works? (Our other system using mmm does not use a tinc vpn, so I can't compare it directly there).


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