On Tuesday 15 September 2020, Anthony Stone wrote:
> On Tuesday 15 September 2020 at 11:45:05, martin doc wrote:
> > What I'm after advice on is how to replicate tables from a number of single
> > host instances of MariaDB to a single HA pair of MariaDB servers
> > (HA-1/HA-2) that have a VIP that moves between them.
> > One way of looking at this might be to say that the single host instances
> > of MariaDB are satellite servers that I need to pull table data back into
> > a primary pair. Kind of like a backup.

> Do you need this to be immediate replication (data written to a single host
> must be replicated immedately to the HA pair) or is a delay of some minutes
> acceptable?

Good question.
A delay of 1 minute or two would be acceptable.
More than 5 minutes, not so much.

> That would be your other problem - you say you have a number of single host
> instances which you want to replicate from, but you can't point a slave at
> more than one master in standard M-M or M-S replication.

I've also used multi-master configurations with GTID before but there's still
the problem of how to restrict the connection accepted on the slave to only
be the host with the VIP.

> a) runs a query on the single hosts to extract updates since the last time the
> query was run, and send this over to the HA pair (eg: rsync and then an
> equivalent script to write into the HA pair, or an SSH tunnel streaming the
> query output into a MariaDB client instance on the HA pair), or

Ok, sounds like I need to write some python to run as a background service
on each of the "satellite" servers that does SELECT/INSERT manually.