Upgrade PostgreSQL version 9 to 10

I had to perform multiple PostgreSQL database upgrades from version 9 to version 10. The database was used for vCloud Director but I believe it is generic enough for other purposes.

The base operating systems I am using is CentOS 7.

Here follows the step-by-step procedure:

1. Create database backup:
   su – postgres
   pg_dumpall > /tmp/pg9backup
   exit
2. Shutdown and uninstall old PostgreSQL v9:
   systemctl stop postgresql-9.5.service
   yum remove postgresql*
3. Archive old datafiles (you will need them later):
   mv /var/lib/pgsql/data/ /data.old
4. Install new PostgreSQL v10:
   yum -y install https://download.postgresql.org/pub/repos/yum/10/redhat/rhel-7-x86_64/pgdg-centos10-10-2.noarch.rpm
   yum -y install postgresql10-server
   systemctl enable postgresql-10
5. Initiate and start DB:
   su – postgres
   /usr/pgsql-10/bin/initdb
   cp /data.old/pg_hba.conf /var/lib/pgsql/10/data/
   cp /data.old/postgresql.conf /var/lib/pgsql/10/data/
   exit
   systemctl start postgresql-10
   
6. Restore backup
   su – postgres
   psql -d postgres -f /tmp/pg9backup
7. Reboot server. If everything works, you can delete your pg9backup and data.old archive.