Hi Johan

On Mon, Oct 30, 2017 at 01:27:50PM +0000, Johan Wassberg wrote:
> > If you load balance behind a single name, is there any way you can
> > ensure that all instances provide the same content?
> Yes, the service is load balanced between two hosts. I didn't thought
> that should be a problem.

It's no problem.  We just flag that as irregularities as the contents
are not the same, even if almost the same.

> How do you normally handle this kind of issues?

Each backend system gets it's own mirror name configured in
ftpsync.conf.  The backends can be reached directly.  How they can be
reached is not important; we have the following mechanisms in the wild:
- The mirrors have public IP on their own and can be reached using it,
- the load balancer exposes the systems directly by name, and
- the load balancer exposes the systems by using different ports.

We will add entries for each backend to our internal mirror list and
make the public name an alias.  We then check each system seperately, so
we can asses the health of each one.  For examples see:
https://mirror-master.debian.org/status/mirror-status.html#&sort[results]=0-0&filter[results]=azure.com--------
https://mirror-master.debian.org/status/mirror-status.html#&sort[results]=0-0&filter[results]=kernel.org--------

Depending on the importance of the mirror we have a bunch of other
things we use to make sure they are in sync, but this does not need to
concern you.

> 2. Allow http access directly to the machines without the load balancer.

For now we would like to start with this one.  You have to select names
for both mirrors and ways to access them.  Currently the backends are
named mirror-prod-debian0[12].it.su.se and are published in DNS with
public IP.  So you could set MIRRORNAME in ftpsync.conf to that hostname
and allow access to the IP from the outside.

Regards,
Bastian
Debian mirror team

-- 
Vulcans believe peace should not depend on force.
                -- Amanda, "Journey to Babel", stardate 3842.3

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