Sometimes, when upgrading to a newer release of CloudBolt, This error occurs:
Restarting rabbitmq-server: RabbitMQ is not running
This usually means one of two things, either the RabbitMQ port is blocked by the firewall, or the DNS server can't resolve the hostname 'cloudbolt'. The latter is the more common of the two.
To check the RabbitMQ port run this command:
Make sure the port number is 4369.
To fix the DNS server not resolving the hostname edit the '/etc/hosts' file and add 'cloudbolt' to the list of hostnames so that the server sees it as 127.0.0.1
The upgrader should run without any errors now.