I have a cluster that has been running pretty smoothly for over a month now that is rather large. I had just fixed an issue with a few DataNodes and was left with the web interface saying that 5 hosts were in maintenance mode when they were not. I tried turning mm on/off but it didn't help so I finally tried a sudo ambari-server restart Afterwards, I tried to login again and the web interface wouldn't load. Waited a few minutes, still nada. Looking at today's entries in /var/log/ambari-server/ambari-server.log had errors regarding the metric server but nothing that seemed relevant. The network settings are all the same and haven't changed, I am not sure what went wrong? Any ideas of what logs I should read or what I should try? EDIT: Thanks for the fast replies!! I have attached the info requested as files so this post doesn't extend down a mile. It looks like the ambari service is not listening on port 8080. EDIT2: I ended up rolling back the ambari server vm to an earlier checkpoint and luckily there weren't too many errors to deal with. I will update again if the issue comes back. ... View more