Recently a number of jobs have been OOMing. I asked on IRC:
13:56:06 <legoktm> I remember someone (dancy probably) saying that there is way to enable larger instances as CI runners, is there docs or pointers on how to do that? 14:01:24 <dancy> legoktm: You can add the `memory-optimized` tag to jobs that need more memory. Right now those are 3.5GB.