We log a bunch of useful info at the top of a docker-worker job. But not instance type! Most users also can't see that in the workerType definitions.
Commits pushed to master at https://github.com/taskcluster/docker-worker https://github.com/taskcluster/docker-worker/commit/0e47adde62bd6d94d18d1d1872159c26d54d4e14 Bug 1289511: log instance type, too https://github.com/taskcluster/docker-worker/commit/9fb079cfda45b1b91d528dc71d680d4710d7956f Merge pull request #236 from djmitche/bug1289511 Bug 1289511: log instance type, too
This was merged and Wander published new amis.