nimbus-reset-state -e deletes SSH keypairs

[priteau]

nimbus-reset-state -e is supposed to reset IaaS databases, the runtime tracking of VM/VMM state, network leases, etc.

It deletes elastic.db, which also contains SSH keypairs uploaded with the EC2 API. Generally an administrator will want to keep these keypairs, so nimbus-reset-state should instead only purge the instances and reservations tables.