Removing OSG Software

While yum is excellent at installing software, it's not very good at removing unused software. As most OSG functional units are spread across many RPMs, it is difficult to remove each RPM individually.

OSG provides a plugin, yum-remove-osg, to assist sysadmins in removing our software. It has two design goals:

  • Remove as many unnecessary RPM packages as possible when one of the top-level packages are removed.
  • Provide strong guarantees that removing OSG software will not damage the rest of the system.

The yum-remove-osg plugin is a fork of the standard remove-leaves plugins, except it will only remove packages if they are only available from a repository considered as part of OSG.

Pitfalls / Gotchas

Please read this section before first using this plugin!

  • The plugin will only remove packages if the corresponding .repo file in /etc/yum.repos.d contains consider_as_osg=yes.
    • All OSG repos have this by default.
    • Packages from EPEL will not be removed by default. OSG uses quite a few packages from EPEL. If you want to remove EPEL packages that got brought in by OSG, add consider_as_osg=yes to the [epel] section in /etc/yum.repos.d/epel.repo.
  • The plugin will only remove packages if they are from an "OSG" repo, and that repo is enabled. If the OSG repo isn't enabled by default, you'll want to add --enablerepo=osg to your yum remove command line.
  • If you remove a package foo, yum will first try to remove all packages that depend on foo, then remove all unused packages.
    • Suppose you have package bar depending on foo and foo depends on baz (and nothing else on the system needs baz). Then, yum remove --osg foo will first remove bar, then foo, then baz.
  • osg-ce depends on osg-client, which depends on osg-wn-client. Hence, if you remove osg-client or osg-wn-client on a CE, then this will remove the CE also.
  • Even with this plugin, yum remove is not the perfect reversal of a yum install command. If you need a perfect reversal, restore from backup. This plugin will be acceptable for many, but not all, sites.
    • For example, if an RPM package installed a Unix user named glexec, the user will remain on the system after the package removal.

Before any action happens, yum will print out the list of packages it will remove. Please review this list before you confirm!

Installing and Using

To install the plugin, do the following with the appropriate osg repo enabled:

[root@client ~]$ yum install yum-remove-osg

Then, to remove a package (such as osg-ce):

[root@client ~]$ yum remove --osg osg-ce

The two prompts above assume that the osg repo is enabled (osg-testing if you are an ITB site).

Topic revision: r3 - 17 Nov 2011 - 19:01:41 - AlainRoy?
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