after trying to express upgrade to 2.6.4 and failing because of Solr mpack, I proceeded to a downgrade back to 2.5.0.
The downgrade finished with:
org.apache.ambari.server.AmbariException: The following 3 host component(s) have not been downgraded to their desired versions:
host3-slave.domain.net: SOLR_SERVER (current = UNKNOWN, desired = 184.108.40.206-1245)
host4-slave.domain.net: SOLR_SERVER (current = UNKNOWN, desired = 220.127.116.11-1245)
host5-slave.domain.net: SOLR_SERVER (current = UNKNOWN, desired = 18.104.22.168-1245)
Because I have installed solr-service-mpack-22.214.171.124.5.tar.gz and the Ambari predict version of Solr is the same as HDP 2.5.0 stack, but it was 126.96.36.199.5 from mpack. This was the same reason why the upgrade did not finished.
Anyway, I removed from all slave hosts the Solr from mpack and succefully deleted Solr service from Ambari. When I try to do a new upgrade without cause of problems, I get those:
Reason: There is an existing downgrade from 188.8.131.52-91 which has not completed. This downgrade must be completed before a new upgrade or downgrade can begin.
I already tried those commands:
[hdfs@host1-master ~]$ hdfs dfsadmin -finalizeUpgrade
Finalize upgrade successful for host1-master.domain.net/184.108.40.206:8020
Finalize upgrade successful for host2-master.domain.net/220.127.116.11:8020
[hdfs@host1-master ~]$ hdfs dfsadmin -rollingUpgrade finalize
FINALIZE rolling upgrade ...
There is no rolling upgrade in progress or rolling upgrade has already been finalized.
I also tried to disable "preUpgradeCheck" in Ambari's experimental mode, but it didn't helped as well. I get:
An internal system exception occurred: Unable to perform upgrade as another downgrade (request ID 449) is in progress.