Node Multi-Tenancy

This guide explains the steps needed to enable node multi-tenancy. This feature enables non-admins to perform API actions on nodes, limited by policy configuration. The Bare Metal service supports two kinds of non-admin users:

  • Owner: owns specific nodes and performs administrative actions on them

  • Lessee: receives temporary and limited access to a node

Setting the Owner and Lessee

Non-administrative access to a node is controlled through a node’s owner or lessee attribute:

baremetal node set --owner 080925ee2f464a2c9dce91ee6ea354e2  node-7
baremetal node set --lessee 2a210e5ff114c8f2b6e994218f51a904  node-10

Configuring the Bare Metal Service Policy

By default, the Bare Metal service policy is configured so that a node owner or lessee has no access to any node APIs. However, the policy policy file contains rules that can be used to enable node API access:

# Owner of node
#"is_node_owner": "project_id:%(node.owner)s"

# Lessee of node
#"is_node_lessee": "project_id:%(node.lessee)s"

An administrator can then modify the policy file to expose individual node APIs as follows:

# Change Node provision status
# PUT  /nodes/{node_ident}/states/provision
#"baremetal:node:set_provision_state": "rule:is_admin"
"baremetal:node:set_provision_state": "rule:is_admin or rule:is_node_owner or rule:is_node_lessee"

# Update Node records
# PATCH  /nodes/{node_ident}
#"baremetal:node:update": "rule:is_admin or rule:is_node_owner"

In addition, it is safe to expose the baremetal:node:list rule, as the node list function now filters non-admins by owner and lessee:

# Retrieve multiple Node records, filtered by owner
# GET  /nodes
# GET  /nodes/detail
#"baremetal:node:list": "rule:baremetal:node:get"
"baremetal:node:list": ""

Note that baremetal:node:list_all permits users to see all nodes regardless of owner/lessee, so it should remain restricted to admins.


Port APIs can be similarly exposed to node owners and lessees:

# Retrieve Port records
# GET  /ports/{port_id}
# GET  /nodes/{node_ident}/ports
# GET  /nodes/{node_ident}/ports/detail
# GET  /portgroups/{portgroup_ident}/ports
# GET  /portgroups/{portgroup_ident}/ports/detail
#"baremetal:port:get": "rule:is_admin or rule:is_observer"
"baremetal:port:get": "rule:is_admin or rule:is_observer or rule:is_node_owner or rule:is_node_lessee"

# Retrieve multiple Port records, filtered by owner
# GET  /ports
# GET  /ports/detail
#"baremetal:port:list": "rule:baremetal:port:get"
"baremetal:port:list": ""


Allocations respect node tenancy as well. A restricted allocation creates an allocation tied to a project, and that can only match nodes where that project is the owner or lessee. Here is a sample set of allocation policy rules that allow non-admins to use allocations effectively:

# Retrieve Allocation records
# GET  /allocations/{allocation_id}
# GET  /nodes/{node_ident}/allocation
#"baremetal:allocation:get": "rule:is_admin or rule:is_observer"
"baremetal:allocation:get": "rule:is_admin or rule:is_observer or rule:is_allocation_owner"

# Retrieve multiple Allocation records, filtered by owner
# GET  /allocations
#"baremetal:allocation:list": "rule:baremetal:allocation:get"
"baremetal:allocation:list": ""

# Retrieve multiple Allocation records
# GET  /allocations
#"baremetal:allocation:list_all": "rule:baremetal:allocation:get"

# Create Allocation records
# POST  /allocations
#"baremetal:allocation:create": "rule:is_admin"

# Create Allocation records that are restricted to an owner
# POST  /allocations
#"baremetal:allocation:create_restricted": "rule:baremetal:allocation:create"
"baremetal:allocation:create_restricted": ""

# Delete Allocation records
# DELETE  /allocations/{allocation_id}
# DELETE  /nodes/{node_ident}/allocation
#"baremetal:allocation:delete": "rule:is_admin"
"baremetal:allocation:delete": "rule:is_admin or rule:is_allocation_owner"

# Change name and extra fields of an allocation
# PATCH  /allocations/{allocation_id}
#"baremetal:allocation:update": "rule:is_admin"
"baremetal:allocation:update": "rule:is_admin or rule:is_allocation_owner"

Deployment and Metalsmith

Provisioning a node requires a specific set of APIs to be made available. The following policy specifications are enough to allow a node owner to use Metalsmith to deploy upon a node:

"baremetal:node:get": "rule:is_admin or rule:is_observer or rule:is_node_owner"
"baremetal:node:list": ""
"baremetal:node:update_extra": "rule:is_admin or rule:is_node_owner"
"baremetal:node:update_instance_info": "rule:is_admin or rule:is_node_owner"
"baremetal:node:validate": "rule:is_admin or rule:is_node_owner"
"baremetal:node:set_provision_state": "rule:is_admin or rule:is_node_owner"
"baremetal:node:vif:list": "rule:is_admin or rule:is_node_owner"
"baremetal:node:vif:attach": "rule:is_admin or rule:is_node_owner"
"baremetal:node:vif:detach": "rule:is_admin or rule:is_node_owner"
"baremetal:allocation:get": "rule:is_admin or rule:is_observer or rule:is_allocation_owner"
"baremetal:allocation:list": ""
"baremetal:allocation:create_restricted": ""
"baremetal:allocation:delete": "rule:is_admin or rule:is_allocation_owner"
"baremetal:allocation:update": "rule:is_admin or rule:is_allocation_owner"