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I think what I am trying to do can be achieved using bash scripts, but I could definitely use some help here ! Ok, here's the scenario:

I have a two-node MySQL cluster with Master-Master replication in place. Now, the application in question (SOGo) runs on those two nodes. At any given point of time, both instances of the application are supposed to read-from/write-to a single replica, to avoid duplicate entries, obviously.

So if instance A is writing to its local database, then B is also writing on that database, remotely. And vice-versa.

If A goes down, then I have to replace a configuration directive in B's SOGo instance to make it use its local database now. A simple sed statement and service restart does this.

After that, when A gets back again, then either I can instruct A to write to B's copy, or ask B to stop writing on its local copy, and instead write to A's copy.

So, to automate this procedure, what would be my best bet ?

Mohit Chawla
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1 Answers1

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You can install heartbeat package to provide the needed functionality. Heartbeat can be configured to assign an IP address called Virtual IP (VIP) to the currently active machine. This IP should be different from the other two IPs assigned to both servers.

So, your application can use this VIP to access the database. When one server fails, the VIP will be moved by heartbeat automatically to the other server. So, your application does not need to be restarted and/or configured to use a different IP. You may just need to check for connection break!

Khaled
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