This page describes the steps required to revert back to the downlevel system after one or more REM nodes have been upgraded.

Rollback procedure

Repeat the following steps for every REM host which was either successfully or unsuccessfully upgraded. For hosts where an upgrade was planned but not yet run, no action is required.

Check for a backup

On any host that was (partially) upgraded, there will be a backup. List the backups using the status command.

> ./orca --hosts remhost1 status
...
backups =
  (#2) 20180503-134400 contains REM:2.6.1.1 Plugins:sentinel-gaa-em-2.8.0.3,sentinel-volte-element-manager-2.8.0.3
...

Look for a backup around the time that the upgrade was carried out (as recorded in the pre-upgrade checklist). If you find one, progress to the rollback-rem command below.

If there is no backup with the appropriate timestamp then orca failed early on in the upgrade process and will not have made any changes to this host, aside from possibly stopping Tomcat. In this case perform the following steps.

  • Log into the host and check if Tomcat is running: ps -ef | grep catalina | grep -v grep

  • If it is not, start it: cd to the directory where Tomcat is installed and run bin/catalina.sh start

With Tomcat restarted you can move on to the next host to rollback.

Run the rollback-rem command

After identifying the backup to rollback to, run the rollback-rem command as follows, replacing <backup ID> with the ID of the backup to roll back to (the number preceding it in the status output, without the leading # symbol).

orca --hosts remhost1 rollback-rem --target <backup ID>

Verify REM services are operating as expected

Follow these steps to verify REM is working as expected.

The rollback procedure for this host is now complete. Move on to the next host to be rolled back.

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