Repos are good. They elevate civilized operating systems above the neolithic systems that expect you to hunt down software and its dependenies, club them on their heads and then drag them back to your server for the final install. Truly, we’re fortunate to beyond such primitive practices.

But what happens if you’re behind a firewall, isolated to what you can dig from out the earth? What happens if you’ve limited bandwidth, and wish to feed a large population of servers, each hungry for the latest and great software updates?

Rsync is the traditional tool, and it does a grand job. It performs intelligently, analyzing the remote source and the local copy, picking out only the differences; thus it is bandwidth efficient. Also because of this, it can resume if interupted. Finally, passed the right options, it’ll cache all its updates until done, so that the repo remains consistent until the everything is in place (--delay-updates).

Unfortuneately, there are times when the remote repo you wish to mirror doesn’t offer rysnc access. The yum-utils rpm package already has a solution to this: reposync. It’s a straight-forward little utility, that’s easy to use. It’s smart about it’s work, detecting when local copies already exist. But coming from yum-utils, it carries some assumptions with it. These assumptions manifest as quirks we’ll have to learn to live with.

Assumption one: it takes a repoid as source. As such, the local system you’re operating from will need to have the repo installed. This assumption bothers me for two reasons. First, hygiene: what if you want to mirror a repo on a system that doesn’t need the software? Yes, the repo can be set to disabled, but still, I like to keep things clean; I’d much rather not install it in the first place. Second, portability: what if you’re constructing a centralized repo server in a heterogenous environment? What if I wanted to use ubuntu as the base OS? Yeah, I could probably mess around with alien to get the software installed, but that’s a lot of effort for an operation that should be relatively simple.

This second point, is probably more my assumption than the utility’s. With a name like reposync, it seems that given a repo it should output a repo. It does not. It dumps to a directory; and so we’ve got a little bit of prep work to do. As such, yum install createrepo.

So what did I do with all of the above? I generated a local copy of VMware’s OS Specific Packages.

Cheat Sheet:

rpm -ivh http://packages.vmware.com/tools/esx/latest/repos/vmware-tools-repo-RHEL6-9.0.5-1.el6.x86_64.rpm
reposync -r vmware-tools-collection -p /var/www/html/vmware/
createrepo /var/www/html/vmware/vmware-tools-collection/
cp /etc/yum.repos.d/vmware-osps.repo /var/www/html/yum.repos.d/vmware-osps-local.repo
vi vmware-osps-local.repo

As a last step, create a cron job to pull in updates.