This popped up in a sensu-client docker container log while running tail from the host.
*** Booting runit daemon... *** Runit started as PID 7 tail: unrecognized file system type 0x794c7630 for ‘/var/log/syslog’. please report this to bug-coreutils@gnu.org. reverting to polling {"timestamp":"2016-09-15T19:30:05.818329+0000","level":"warn","message":"loading config files from directory","directory":"/etc/sensu"} # uname -r 4.4.0-36-generic # lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 14.04.5 LTS Release: 14.04 Codename: trusty # docker info Containers: 4 Running: 4 Paused: 0 Stopped: 0 Images: 179 Server Version: 1.12.1 Storage Driver: overlay2 Backing Filesystem: extfs Logging Driver: json-file Cgroup Driver: cgroupfs Plugins: Volume: local Network: host null bridge overlay Swarm: inactive Runtimes: runc Default Runtime: runc Security Options: apparmor Kernel Version: 4.4.0-36-generic Operating System: Ubuntu 14.04.5 LTS OSType: linux Architecture: x86_64 CPUs: 2 Total Memory: 1.954 GiB Docker Root Dir: /var/lib/docker Debug Mode (client): false Debug Mode (server): false Registry: https://index.docker.io/v1/ WARNING: No swap limit support Please let me know if you need/want anything else. Damion Waltermeyer DevOps Connectify -- -- http://www.connectify.me/ This email message is for the sole use of the intended recipient(s) and may contain Connectify confidential or privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not an intended recipient, please contact the sender by reply email and destroy all copies of the original message.