After upgrading from 1.6 to 1.7.3 you are not able to launch DC/OS UI
Steps taken to resolve
systemctl list-units| grep dcos
you may see a problem with "dcos-gunicorn-bouncer.service" it is not getting started.
It appears as
jdcos-gunicorn-bouncer.service loaded activating
You see an error in the journalctl log
Process: 12547 ExecStart=/opt/mesosphere/packages/bouncer--415369472893c05b041e9003ee9b672cfc12a70e/bouncer/bin/bouncer-gunicorn.sh (code=exited, status=2'''
Reviewing the bouncer json,
& using a jsonlint, here http://jsonlint.com/ showed it was invalid.
We figured out that the bouncer-config.json was formatted incorrectly due to a typo in the creation of the DC/OS 1.8 config.yaml
should have been
Reference: https://docs.mesosphere.com/1.7/administration/installing/custom/cli/ Section: "Create configuration file"
The DC/OS UI became available after executing
sed 's/True/true/g' /opt/mesosphere/etc/bouncer-config.json