No idea what's going on here. How can it not find that class? It's defined at manifests/role/ci.pp and used to work fine.
Apr 2 22:34:44 integration-slave-precise-1011 puppet-agent[16458]: Could not retrieve catalog from remote server: Error 400 on SERVER: Could not find class role::ci::slave::labs for i-00000a44.eqiad.wmflabs on node i-00000a44.eqiad.wmflabs