[Koha] Load Balancing with Koha

[Dave Sherohman]

On Tue, Dec 04, 2018 at 02:35:39PM +0200, Mutsikiwa Admire wrote:
> Just wondering if it is possible to have a Koha implementation in which we
> have a front-end Load Balancer such as NGINX or HAProxy, several Koha  web
> server instances powered by one database server running on a separate server
> with balancing from source with stick-table in the case of HAProxy.

Yep!  I'm currently handling the sysadmin side of an installation which
runs the koha web interface on two mirrored web servers behind an F5
BIG-IP load balancer, with a third non-web server to handle cron jobs,
outgoing mail, etc.  All three servers talk to a three-node
mariadb/galera cluster (although they only actually talk to a single
node because koha doesn't play well with multi-master database
configurations) for data storage and a five-node elasticsearch cluster
for indexing.

On each individual web server (after passing through the load balancer),
the request path is nginx => apache => starman/plack.  nginx serves
static files, apache handles shibboleth authentication, and starman runs
the koha scripts.

I opted to go with the F5 device instead of nginx for the front-end load
balancing because it was already available through the campus data
center and I didn't want to deal with setting up failover on an IP
address myself, but I can't see any reason that it wouldn't work just as
well (from koha's perspective) with nginx or haproxy as the load
balancer instead of a dedicated device.

-- 
Dave Sherohman