unsuccessful upgrade, I was forced to completely remove HDP 2.4, Ambari 2.5 and
install HDP 2.6. I wanted to avoid reinstalling the OS, so I took advantage of this instruction. Unfortunately, it is not complete. For the problem-free
installation of HDP 2.6, you also need to do things like removing service
users, cleaning the cron.
is my plan of action:
all services in Ambari or kill them. In my case, Ambari damaged his database
during downgrade and could not start. So I manually killed all the processes on
ps –u hdfs (see list of all services below)