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Owl River Company - Yum hints

We maintain several usage hints, which we have compiled over time using yum as an enabling technology in our systems administration practice. The home yum site is at the Duke LUG, and its lead maintainer is seth vidal. The yum Bugzilla is here. As these are a mouthful to remember and type (as when using lynx, w3m, or another textish web browser to go find a download, we maintain a 'convenience' shortcut URL at: http://www.owlriver.com/yum/

Using yum as a upgrade tool

We document Using yum to upgrade from Red Hat 8 to Red Hat 9, Red Hat Linux 7.3 to Red Hat Linux 8 Upgrade steps using 'yum' and Using yum to upgrade from cAos-1 to CentOS-3. We publish a more formal 'Tip' Using yum to upgrade from Red Hat Linux 9 to CentOS 3.1. We have used yum to move from as far back as Red Hat 7.2 to Centos-3. We have used it to move from Aurora 0.4 to Aurora 1.0 on that RPM based Sparc port.

Using yum as a chroot building tool

We have documented using yum as a tool to build a 'chroot' filesystem instance, in which to build packages. A 'chroot' instance is very useful for porting purposes, and indeed for day-to-day maintenance work, as it permits having a pristine 'sandbox' in a known state, clean of any unknown packages in the build environment.

Using yum as a build requirement dependency resolution and installation tool

We have documented using yum as a tool to assist getting the build environment complete, within a build 'chroot' filesystem instance (and indeed to do non-root, chroot based building). This code provided the basis of the cAos project build engine as that project began work.

Using yum as a server side 'up2date' management analogue

We published a generalized yum.conf web based CGI provider, back in February 2003, and released it to the community under the GPL. That was described here.

Red Hat has not released under an open source license, the code, or a full API for their 'up2date' tool. This is an approach to replicating some of that functionality.

For the cAos project, and its commercial adjunct CentOS (for each of which, we offer commercial support in our wings product family at: http://www.owlriver.com/wings/), we recently wrote a variant to handle load balancing in a mixed constellation of HTTP and FTP mirrors. A GPL subset stub is available as: yum-redirect.php here.

The approach of yum-redirect.php is somewhat sub-optimal, because yum does not remotely update its pointer of the archive to use; that is, it keeps re-querying the dispatcher. A change in yum as to archive redirect detection would be needed to make this more userful in a heavy load circumstance; there are. however, security concerns as to so-called Man in the Middle (also called "MitM", or even Monkey in the Middle after Dug Song's work with dsniff). Alternately at the provisioning site, putting the central redirector behind a load balancing tool would work, but all slave units behind the load balancer would need to access the same dispatch decision code results (which is currently a hardcoded set of variables in this demonstration stub.)

The release code points (as of January 2004) to an adjunct 'yum ready' archive for a cAos-1 pre-release variant. We offer support use of a larger and more complex variant of this code, with keying to our commercial support resources in production on our server side. We gratefully acknowledge the comments and testing assistance of Jacob Wilkins ('Bacon' on the cAos IRC at irc.freenode.net, channel #caos).

Yum and RPM versions post by seth: rpm-4.2

Other voices

GUI front ends for yum are often requested. There are two examples: yumgui, and yumtk.

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Last modified: Mon, 21 Jun 2004 14:27:31 -0400