I am trying to remove a node from a cluster but the machine itself is no longer around. We removed the node from the database before decommissioning it but did not realized it needed to be removed from the cluster as well.
Can you try dropping the node?
DROP NODE <<node_name>> CASCADE;
If that does't work, you'll have to use the catalog editor to remove the node. Do you have Vertica Support? If so, open a support case and they can help you do that.