I would like to downgrade Ambari server (from 2.7.3 to 2.6.2). This is a new installation and since Ambari was never upgraded, there are no database back up files (as referenced here: https://community.hortonworks.com/questions/175812/downgrade-procedure-from-ambari-version-2610-to-lo.html). Therefore, I modified the instructions as follows (omitting the old database import steps and re-running ambari-server setup). Will this work without negatively affecting the other HDP 2.6.4 components? If not, is there a procedure to downgrade Ambari in a new installation? 1. Stop the ambari-server. # ambari-server stop 2. Stop all the ambari-agents on all hosts. # ambari-agent stop 3. Download the ambari.repo of the downgraded version on all agent hosts and ambari server host. Example: # wget -nv http://public-repo-1.hortonworks.com/ambari/centos7/2.x/updates/2.4.2.0/ambari.repo -O /etc/yum.repos.d/ambari.repo 4. (omitting this step) Then take a backup of "/etc/ambari-server/conf" and "/etc/ambari-agent/conf" directories (for backup). 5. Erase the ambari Binaries from Ambari Server and Ambari Agent hosts like (basically cleaning up the Ambari Server and agent binaries) yum remove ambari-server ambari-agent rm -f /usr/sbin/ambari* rm -f /usr/lib/python2.6/site-packages/ambari_commons rm -f /usr/lib/python2.6/site-packages/ambari_server rm -rf /usr/lib/python2.6/site-packages/resource_management rm -rf /usr/lib/python2.6/site-packages/ambari_jinja2 rm -f /usr/lib/python2.7/site-packages/ambari_commons rm -f /usr/lib/python2.7/site-packages/ambari_server rm -rf /usr/lib/python2.7/site-packages/resource_management rm -rf /usr/lib/python2.7/site-packages/ambari_jinja2 rm -rf /var/lib/ambari-server rm -rf /var/lib/ambari-agent/ rm -rf /usr/lib/ambari-agent/ rm -rf /usr/lib/ambari-server/ 6. Perform yum cleanup # yum clean all 7. (omitting this step) Import the OLD Database Dump of previous ambari version to the Database. (for example ambari 2.4.2 DB dump) # su postgres -c 'psql -c "drop database ambari" ' # su postgres -c 'psql -c "create database ambari" ' # su postgres -c 'psql -f ./ambari_old_242.sql -d ambari' 8. Install ambari-server and ambari agents (agent on all hosts) # yum install ambari-server ambari-agent -y (On Ambari Server) # yum install ambari-agent -y (On all cluster nodes) 9. Rerun ambari-server setup # ambari-server setup 10. Start ambari agents and ambari server. # ambari-server start # ambari-agent start ... View more