title: Changes to Repository Sync

layout: post

Void is a complex system, and over time we make changes to reduce this

complexity, or shift it to easier to manage components. Recently

through the fantastic work of one of our maintainers `classabbyamp`

our repository sync system has been dramatically improved.

Previously our system was based on a series of host managed rsyncs

running on either snooze or cron based timers. These syncs would push

files to a central location to be signed and then distributed. This

central location is sometimes referred to as the "shadow repo" since

its not directly available to end users to synchronize from, and we

don't usually allow anyone outside Void to have access to it.

As you might have noticed from the [Fastly

Overview](/news/2023/02/1-new-repo-fastly.html) the packages take a

long path from builders to repos. What is not obvious from the graph

shown is that the shadow repo previously lived on the musl builder,

meaning that packages would get built there, copied to the glibc

builder, then copied back to the musl builder and finally copied to a

mirror. So many copies! To streamline this process, the shadow

mirror is now just the glibc server, since that's where the packages

have to wind up for architectural reasons anyway. This means we were

able to cut out 2 rsyncs and reclaim a large amount of space on the

musl builder, making the entire process less fragile and more

streamlined.

But just removing rsyncs isn't all that was done. To improve the time

it takes for packages to make it to users, we've also switched the

builders from using a time based sync to using lsyncd to take more

active management of the synchronization process. In addition to

moving to a more sustainable sync process, the entire process was

moved up into our Nomad managed environment. Nomad allows us to more

easily update services, monitor them for long term trends, and to make

it clearer where services are deployed.

In addition to fork-lifting the sync processes, we also forklifted

void-updates, xlocate, xq-api (package search), and the generation of

the docs-site into Nomad. These changes represent some of the very

last services that were not part of our modernized container

orchestrated infrastructure.

Visually, this is what the difference looks like. Here's before:


And here's what the sync looks like now, note that there aren't any

cycles for syncs now:


*If you run a downstream mirror we need your help!* If your mirror

has existed for long enough, its possible that you were still

synchronizing from alpha.de.repo.voidlinux.org, which has been a dead

servername for several years now. Since moving around sync traffic is

key to our ability to keep the lights on, we've provisioned a new

dedicated DNS record for mirrors to talk to. The new

`repo-sync.voidlinux.org` is the preferred origin point for all sync

traffic and using it means that we can transparently move the sync

origin during maintenance rather than causing an rsync hang on your

sync job. Please check where you're mirroring from and update

accordingly.