bifrost文档中的“ clouds”是什么意思？

Question

当我读到documentation时：

clouds.yaml¶
During installation, Bifrost creates a clouds.yaml file with credentials necessary to access Ironic. A cloud called bifrost is always available. For example:

> export OS_CLOUD=bifrost
> openstack baremetal node list


In noauth mode, a cloud called bifrost-inspector is also included that allows access to the Ironic Inspector API. For example:

> export OS_CLOUD=bifrost-inspector
> openstack baremetal introspection list

1. 我不明白那里的clouds的含义。
2. 如果我们配置export OS_CLOUD=bifrost，那么为什么可以访问Ironic？