After having had some issues with the new default Solr port in Rosetta 5.4.0.0, I suggest creating a startup checker plugin for Rosetta to test for Solr availability. Possible error scenarios involve:
1.) network down
2.) Name resolution down/misconfigured
3.) Solr default port closed in the local firewall / Solr not listening

1. & 2. could be checked by pinging the other servers' DNS names (NOT the IPs), which would test network availability and DNS resolution in one step. As Rosetta servers usually are located in the same subnet, we don't have to worry about ICMP firewall restrictions.
2. could be tested by using "$> telnet $HOSTNAME $PORT", like "$> telnet rosetta-host-1 8983" and SSH-ing into the remote systems to list processes listening on specific ports, like "netstat -tulpn | grep 8983" or "ss -tulpn | grep 8983".