Mocking RPMs on CentOS
Mock is a Fedora project that allows you to build RPM packages within a chroot environment, allowing you to build packages for other systems than the one you're running on (e.g. building CentOS 4 32-bit RPMs on a CentOS 5 64-bit host), and ensuring that all the required build dependencies are specified correctly in the RPM spec file.
It's also pretty under-documented, so these are my notes on things I've figured out over the last week setting up a decent mock environment on CentOS 5.
First, I'm using mock 1.0.2 from the EPEL repository, rather than older 0.6.13 available from CentOS Extras. There are apparently backward-compatibility problems with versions of mock > 0.6, but as I'm mostly building C5 packages I decided to go with the newer version. So installation is just:
# Install mock and python-ctypes packages (the latter for better setarch support) $ sudo yum --enablerepo=epel install mock python-ctypes # Add yourself to the 'mock' group that will have now been created $ sudo usermod -G mock gavin
The mock package creates an /etc/mock directory with configs for various OS
versions (mostly Fedoras). The first thing you want to tweak there is the
site-defaults.cfg file which sets up various defaults for all your builds. Mine now
looks like this:
# /etc/mock/site-defaults.cfg # Set this to true if you've installed python-ctypes config_opts['internal_setarch'] = True # Turn off ccache since it was causing errors I haven't bothered debugging config_opts['plugin_conf']['ccache_enable'] = False # (Optional) Fake the build hostname to report config_opts['use_host_resolv'] = False config_opts['files']['etc/hosts'] = """ 127.0.0.1 buildbox.openfusion.com.au nox.openfusion.com.au localhost """ config_opts['files']['etc/resolv.conf'] = """ nameserver 127.0.0.1 """ # Setup various rpm macros to use config_opts['macros']['%packager'] = 'Gavin Carr <[email protected]>' config_opts['macros']['%debug_package'] = '%{nil}'
You can use the epel-5-{i386,x86_64}.cfg configs as-is if you like; I copied them
to centos-5-{i386,x86_64}.cfg versions and removed the epel 'extras', 'testing',
and 'local' repositories from the yum.conf section, since I typically want to build
using only 'core' and 'update' packages.
You can then run a test by doing:
# e.g. initialise a centos-5-i386 chroot environment $ CONFIG=centos-5-i386 $ mock -r $CONFIG --init
which will setup an initial chroot environment using the given config. If that seemed to work (you weren't inundated with error messages), you can try a build:
# Rebuild the given source RPM within the chroot environment # usage: mock -r <mock_config> --rebuild /path/to/SRPM e.g. $ mock -r $CONFIG --rebuild ~/rpmbuild/SRPMS/clix-0.3.4-1.of.src.rpm
If the build succeeds, it drops your packages into the /var/lib/mock/$CONFIG/result
directory:
$ ls -1 /var/lib/mock/$CONFIG/result build.log clix-0.3.4-1.of.noarch.rpm clix-0.3.4-1.of.src.rpm root.log state.log
If it fails, you can check mock output, the *.log files above for more info, and/or
rerun mock with the -v flag for more verbose messaging.
A couple of final notes:
the chroot environments are cached, but rebuilding them and checking for updates can be pretty network intensive, so you might want to consider setting up a local repository to pull from. mrepo (available from rpmforge) is pretty good for that.
there don't seem to be any hooks in mock to allow you to sign packages you've built, so if you do want signed packages you need to sign them afterwards via a
rpm --resign $RPMS.