Connection refused from Karaf Shell after upgrade to Horizon 24

If you are no longer able to login to the Karaf Shell (e.g. ssh admin@localhost -p 8101) it is very likely, that the entry for the user in in ${OPENNMS_HOME}/etc/ is missing the role ssh.

Ensure that the user is assigned to the group admingroup and that group is assigned the ssh role.

admin = admin,_g_:admingroup
_g_\:admingroup = group,admin,manager,viewer,systembundles,ssh

See here for the full file.