Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin

sean1 — Wed, 14 Aug 2019 13:00:09 GMT

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

Re: Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin

jsensharma — Mon, 19 Aug 2019 07:43:33 GMT

@sean1

As you mentioned that . "This is a new installation and since Ambari was never upgraded," .... "there are no database back up files"

1. If this a new installation then what is the reason for downgrading ambari?

If ambari was never upgraded (as it is a new installation) then what is the need to downgrade it ?

2. If you do not have the Ambari DB backup then you can not recover the cluster installation even if you installed the Ambari 2.6.2 (So backup is must)

Re: Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin

sean1 — Mon, 19 Aug 2019 18:05:20 GMT

@jsensharma,

Thank you very much for your prompt reply and clear answer.

The reason for wanting to downgrade was to avoid a complete re-install (for logistical reasons). The version should have been 2.6.2.0 per spec request.

question Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin in Support Questions

Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin

Re: Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin

Re: Downgrade Ambari 2.7.3 to 2.62 on New HDP 2.6.4 Installatioin