We are currently using Cloudera Express 5.10.0 on Ubuntu 14.04.5. This cluster was installed using cloudera manager.

We need to ugprade to Ubuntu 16.04 as 14.04 is approaching EOL. What is the recommended process?

Do we upgrade Cloudera first and then Ubuntu or Ubuntu first and then Cloudera?

I have tried to upgrade ubuntu first. But Ubuntu (do-release-upgrade) upgrades postgres from 9.3 to 9.5. Since the database formats between 9.3 and 9.5 are not compatible, the cloudera-scm-server-db doesn't start. I have tried to migrate the database using pg_dump/pg_restore etc but have failed so far.

If there is a document available somewhere, please let me know.