As of 11121.0.0 there's a big spike in the number of failures in the CrostiniFiles and CrostiniStartEverything tests.

Here's a link to the test results:

https://stainless.corp.google.com/search?exclude_retried=true&first_date=2018-09-27&master_builder_name=&builder_name_number=&shard=&exclude_acts=true&builder_name=&master_builder_name_number=&owner=&retry=&exclude_cts=true&exclude_non_production=false&hostname=&board=&test=%5Etast%5C.vm%5C.CrostiniFiles%24&suite=&build=%5ER71%5C-11121%5C.0%5C.0%24&status=FAIL&status=ERROR&status=ABORT&reason=&waterfall=&exclude_not_run=false&last_date=2018-10-03&exclude_non_release=true&exclude_au=true&model=&view=list

I did a summary of all of the ones from this version here, and where they are failing. Nothing is really consistent between them, but something got broken in 11121.0.0 that's causing this. 

I also reproduced this on my first try with vm.CrostiniStartEverything on a kefka board, so this shouldn't be hard to reproduce.

sand - CrostiniFiles - timeout after starting lxd (no BTRFS lines)
sand - CrostiniStartEverything - timeout after starting lxd (with BTRFS lines)
celes - CrostiniFiles - timeout after starting lxd (with BTRFS lines)
celes - CrostiniStartEverything - timeout with failed mounting 9P server (occurs after starting lxd and before BTRFS lines)
relm - CrostiniFiles - timeout after lxd startup at a random point
setzer - CrostiniFiles - hung after SetupUser
nautlius - CrostiniFiles - hung task problem ( crbug.com/891806 )
nautilus - CrostiniStartEverything - timeout after starting lxd (no BTRFS lines)
nautliuslte - CrostiniFiles - hung task problem ( crbug.com/891806 )
nautilislte - CrostiniStartEverything - timeout after starting lxd (with BTRFS lines)
nami - CrostiniFiles - timeout after starting lxd (with BTRFS lines)
nami - CrostiniStartEverything - hung task problem ( crbug.com/891806 )
pantheon - CrostiniFiles - timeout starting the container
pantheon- CrostiniStartEverything - timeout after starting lxd (no BTRFS lines)
banon - CrostiniFiles - timeout stopping VM
banon - CrostiniStartEverything - container not found problem (this was seen the day before as well, so likely not related to this one)

Please get the tree green...we were almost there. :)