ironic-specs/specs/liberty/enroll-node-state.rst

Add "enroll" state to the state machine

https://blueprints.launchpad.net/ironic/+spec/enroll-node-state

This blueprint introduces a new state called enroll, which we previously agreed to introduce in the new state machine spec.

Problem description

Currently nodes on creation are put into available state, which is designed as a replacement for NOSTATE. Such nodes will instantly be available to Nova for deployment, provided they have all the required properties.

However, the new state machine lets the operator perform inspection on a node and zapping of a node. The state machine allows for them to be done before a node reaches the available state.

Even worse, the cleaning feature introduced in Kilo cycle should also happen before a node becomes available.

Proposed change

• Add a new state enroll, from which a node can transition into the manageable state by an action called manage.

• manage transition will cause power and management interfaces to be validated on the node. Also an attempt will be made to get the power state on a node to actually verify the supplied power credentials.

  On success, the node will go to the manageable state. On failure, it will go back to the enroll state and last_error will be set.

• Disable the sync_power_state for nodes in the enroll state, as nodes in this state are not expected to have valid power credentials.

• Introduce a new API microversion, making newly created nodes appear in the enroll state instead of the available state.

  After that the client-server interaction will be the following:

  • new client (with new API version) + new server: nodes appear in the enroll state.
  • new client + old server: client gets a response from the server stating that node is in available (or none) state. Client issues a warning to the user.
  • old client (or new client with old API version) + new server: due to versioning the node will appear in available (or none) state.

• Document that we are going to make a breaking move to the enroll state by default.

• Update DevStack gate to explicitly request the new microversion and fix the tests.

• Release a new version of ironicclient defaulting to this new microversion. Clearly document this breaking change in upgrade notes.

Alternatives

We can ask people to manually move nodes to the manageable state before inspection or zapping. We also won't validate power and management interfaces.

Data model impact

None

State Machine Impact

• enroll becomes a valid node state with transitions to:
  • verifying via manage action
• verifying becomes a valid transient node state with transitions to:
  • manageable on done
  • enroll on fail and last_error will be set.

REST API impact

• Add new API microversion. When it is declared by client, node creation API should default to creating nodes in the enroll state.

Client (CLI) impact

• New release of client will be issued defaulting to the new microversion (and breaking many flows).

RPC API impact

None

Driver API impact

None

Nova driver impact

• Double check that Nova driver won't use nodes in enroll state
• Sync nova/virt/ironic/ironic_states.py for the sake of consistency

No functionality impact expected.

Security impact

None expected

Other end user impact

With the new microversion, nodes will appear in the enroll state. Two more steps should be taken to make them available for deploy: manage and provide. Cleaning will happen, if enabled.

Scalability impact

None

Performance Impact

None

Other deployer impact

See Upgrades and Backwards Compatibility.

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Dmitry Tantsur, IRC: dtantsur, LP: divius

Other contributors:

None

Work Items

• Create new states and transitions
• Introduce new microversion with node defaulting to enroll on creation
• Make sure our tests do not break (fix devstack etc)
• Default ironicclient to the new microversion

Dependencies

None

Testing

• Tempest tests should be modified to test enroll state.

Upgrades and Backwards Compatibility

• Change is backwards compatible, while it's not the default in ironicclient.
• Once new microversion is the default in ironicclient, it will break existing flows, when explicit microversion is not in use.

Documentation Impact

• Working with the new state and the transition should be documented
• Upgrade notes should be updated

References