====== Upgrade Graylog server from el7 to el8 ======

  * Install a new server with EL8, using our [[https://ks.fws.fr/el8.ks|kickstart file]]
  * On the old server, stop graylog and backup its mongo database

<code bash>
systemctl stop graylog-server
pre-backup
# Copy /home/lbkp/mongo/graylog somewhere
</code>

  * Shutdown the old server and start the new one with the same IP
  * Ensure log listeners won't be accessible yet (either disable rules on the main firewall, or set graylog_http_src_ip to an empty array)
  * Run the ansible playbook :

<code bash>
ansible-playbook -i inventories/fws.ini fws.yml -l graylog.fws.fr
</code>
  * Stop Graylog service, copy the mongo dump on the new server, and restore graylog's mongo database

<code bash>
systemctl stop graylog-server
mongo graylog --eval "db.dropDatabase()"
mongorestore -d graylog /home/lbkp/mongo/graylog/
systemctl start graylog-server
</code>