Debugging openstack ....logs , services e.t.c

Something is broken ...
lets say heat is not starting up ..
what do we do ?

calm down!
check logs ( /var/log/heat-api.log,  /var/log/heat-api-cfn.log, /var/log/heat-engine.log)

Do you see any errors there ?? ( most of the times this should be sufficient)

but what if there is not error in the logs.. since the service is not even starting ?
try restarting the service(systemctl comes to rescue)

systemctl list-units |grep heat

systemctl status openstack-heat-api.service

systemctl status openstack-heat-api-cfn.service

systemctl status openstack-heat-engine.service

Just getting a failed status but no details ?try debugging

journalctl -u openstack-heat-api-cfn.service

here are few links which will help

https://access.redhat.com/articles/systemd-cheat-sheet

https://cdn.rawgit.com/ruzickap/linux.xvx.cz/gh-pages/files/systemd_cheatsheet/systemd_cheatsheet.pdf