Here’s a little snippet I use to remove multiarch / i386 support from Ubuntu with Puppet.
if versioncmp( $::lsbdistrelease, "12.04" ) > 0 {
exec { "remove-architecture i386":
command => "/usr/bin/dpkg --remove-architecture i386",
onlyif => "/usr/bin/dpkg --print-foreign-architectures | /bin/grep -q i386",
}
} else {
file { "/etc/dpkg/dpkg.cfg.d/multiarch": ensure => absent, }
}