@glenngould Yep, that means your docker service isn't running and probably is hanging on some dependent modules.
First off, based on your shell status, you're running as root.
I've tried "sudo docker ps" but no output...
So you don't need sudo (superuser do). You can just run the commands below without that.
It should output all the failed units within systemd:
# systemctl --failed
UNIT LOAD ACTIVE SUB DESCRIPTION
● kdump.service loaded failed failed Crash recovery kernel arming
kdump.service "failing" is normal and will only activate when trying to capture a kernel dump, which you aren't experiencing at the moment.
The Docker / Rockstor services rely on the rockstor.service and the rockstor-bootstrap.service, so if these are failing then you have big problems. But since you're able to get to the dashboard I think you're okay here.
There are 2 sysd units that should be running related to Docker / Rock-ons:
● docker.socket - Docker Socket for the API
Loaded: loaded (/etc/systemd/system/docker.socket; disabled; vendor preset: disabled)
Active: active (running) since Wed 2017-01-11 17:20:23 MST; 1 day 6h ago
Listen: /var/run/docker.sock (Stream)
● docker.service - Docker Application Container Engine
Loaded: loaded (/etc/systemd/system/docker.service; enabled; vendor preset: disabled)
Active: active (running) since Wed 2017-01-11 17:20:38 MST; 1 day 6h ago\
These both should be Active status. To check these individually, run this:
systemctl status docker.socket
systemctl status docker.service