[routing-wg] Changes to the RRDP repository

Dear colleagues,

Over the past months, we have been working on the RIPE NCC RPKI repositories.
We have an update to the RRDP repository that we plan to deploy on 9 November.
This will create a regular RRDP event (a session change) but will have no other
externally visible impact. We want to share some of the improvements this change
has to offer and highlight two areas in particular. 

First, we have improved the publication server software [0]. The current
publication server uses an embedded NoSQL/schemaless database. We have changed
the project to use PostgreSQL instead, which allows us to move several integrity
checks to the publication server’s database.

Second, we have changed how the publication server is deployed, which is part of
our work to move components of our infrastructure on-premise. Initially, we will
run two independent instances, with separate database servers and data centres,
with each instance receiving all objects in the repository. We aim to keep this
simple at an initial stage, closely monitor how the environment behaves, and
expand later if we need to. Because the RRDP session differs between the
instances, one instance is (and can be) active at each moment in time. This
allows us to swap them out during an upgrade and allows us to fall back to the
second one if any issue is being detected.

Both instances are behind a load-balancer, which is the origin for the Content
Delivery Network (CDN) that we use. By using a CDN, we (a) reduce the latency
from various geographical locations, (b) protect ourselves from network glitches,
and (c) reduce the bandwidth peak after a session change that would interfere
with other services on the RIPE NCC network (for example during a deployment). 

This change is an intermediate step in our work on the resiliency of our
publication infrastructure. We have extensively looked at possible architectures
that can solve the issues we are facing now and considered numerous failure
modes, and we think this design strikes a good balance between resilience and
simplicity. 

We will discuss our architectural changes with the community at RIPE 83 and look
forward to hearing your feedback.

If you have any questions, please get in touch with us. 

Kind regards,
Ties de Kock

[0]: https://github.com/RIPE-NCC/rpki-publication-server