If two jobs are pulling the same image simultaneously, which ever starts the pull first will set the pull timeout.
This can lead to a poor UX where the first job requested a short timeout while the second job requested a longer timeout
causing the pull to potentially timeout much sooner than expected by the second job.
* alloc_runner
* Random tests
* parallel task_runner and no exec compatible check
* Parallel client
* Fail fast and use random ports
* Fix docker port mapping
* Make concurrent pull less timing dependant
* up parallel
* Fixes
* don't build chroots in parallel on travis
* Reduce parallelism on travis with lxc/rkt
* make java test app not run forever
* drop parallelism a little
* use docker ports that are out of the os's ephemeral port range
* Limit even more on travis
* rkt deadline
This PR introduces a coordinator for doing CRUD on a Docker image. It
should fix racy deletion of images. The issue before was images would be
deleted between prestart and start causing an error.
