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Howdy.

I'm working with a group of people who are interested in enabling some
form of baremetal leasing/reservations using Ironic.  There are three
key features we're looking for that aren't (maybe?) available right
now:

- multi-tenancy: in addition to the ironic administrator, we need to
  be able to define a node "owner" (someone who controls a specific
  node) and a node "consumer" (someone who has been granted temporary
  access to a specific node).  An "owner" always has the ability to
  control node power or access the console, can mark a node as
  available or not, and can set lease policies (such as a maximum
  lease lifetime) for a node.  A "consumer" is granted access to power
  control and console only when they hold an active lease, and
  otherwise has no control over the node.

- leasing: a mechanism for marking nodes as available, requesting
  nodes for a specific length of time, and returning those nodes to
  the available pool when a lease has expired.

- hardware only: we'd like the ability to leave os provisioning up to
  the "consumer".  For example, after someone acquires a node via the
  leasing mechanism, they can use Foreman to provisioning an os onto
  the node.

For example, a workflow might look something like this:

- The owner of a baremetal node makes the node part of a pool of
  available hardware. They set a maximum lease lifetime of 5 days.

- A consumer issues a lease request for "3 nodes with >= 48GB of
  memory and >= 1 GPU" and "1 node with >= 16GB of memory and >= 1TB
  of local disk", with a required lease time of 3 days.

- The leasing system finds available nodes matching the hardware
  requirements and with owner-set lease policies matching the lease
  lifetime requirements.

- The baremetal nodes are assigned to the consumer, who can then
  attach them to networks and make use of their own provisioning tools
  (which may be another Ironic instance?) to manage the hardware. The
  consumer is able to control power on these nodes and access the
  serial console.
  
- At the end of the lease, the nodes are wiped and returned to the
  pool of available hardware. The previous consumer no longer has any
  access to the nodes.

Our initial thought is to implement this as a service that sits in
front of Ironic and provides the multi-tenancy and policy logic, while
using Ironic to actually control the hardware.

Does this seem like a reasonable path forward? On paper there's a lot
of overlap here between what we want and features provided by things
like the Nova schedulers or the Placement api, but it's not clear
we can leverage those at the baremetal layer.

Thanks for your thoughts,

-- 
Lars Kellogg-Stedman <lars at redhat.com> | larsks @ {irc,twitter,github}
http://blog.oddbit.com/                |