ironic-specs/specs/approved/inspection-abort.rst

Support baremetal inspection abort

https://bugs.launchpad.net/ironic/+bug/1703089

This spec aims to support aborting node inspection from ironic API. A dependency of inspect wait state in¹ is required for this spec to continue.

Problem description

Currently, we can't abort the process of node inspection from ironic API. When a node is not properly setup under inspection network, admins can only wait it to fail after specified timeout, or abort the inspection process from ironic inspector API/CLI (if the in-band inspect interface inspector is in use).

Although the inspection state will be synchronized to ironic by periodic task, it's not consistent for an operation started from ironic, then stopped by inspector, furthermore, it creates a little delay of time. Node state is inconsistent between ironic and inspector until next state synchronization. The default time interval for ironic-inspector state synchronization is 60 seconds, it may vary depending on user configuration.

Proposed change

Add state transition of inspect wait to inspect failed to state machine, add support to ironic to allow the verb abort can be requested when node in inspect wait state.

Add a method named abort into InspectInterface, so that inspect interface can provide implementation to support inspection abort. The default behavior is to raise an UnsupportedDriverExtension exception. Implement the abort operation for inspector inspect interface.

When an abort operation is requested from ironic API, and the node in the state of inspect wait, ironic calls abort method from inspect interface of driver API, and moves node state to inspect failed if the method executed successfully.

Note that, the abort request to ironic-inspector is asynchronous, ironic will move node to inspect failed once the request is accepted (202), disregard if the operation at ironic-inspector is performed successfully. This reduces the design complexity for this feature by handling failure at the side of ironic-inspector.

From the point of view of ironic-inspector, every inspect request will refresh local cache for the node, it assures that node state is in sync when starting node inspection. However, inconsistent node state do exist if abort request is accepted but not performed successfully at ironic-inspector. This inconsistency will be eliminated by ironic-inspector node cache clean up when timeout is reached.

Involved changes are:

• Add a method named abort() to base inspect interface (InspectInterface).
• Implement abort() for inspector inspect interface.
• Implement the logic for ironic handling the verb abort when provisioning state is inspect wait.

Alternatives

• Wait for inspect fail after specified timeout value.
• Request through ironic-inspector api or openstack baremetal introspection abort command. Be aware that it's only viable when using ironic inspector as inspect interface. Other inspect interfaces like out-of-band inspection may have different approach to achieve the same goal, that is beyond the scope of this spec.

Data model impact

None

State Machine Impact

Add a state transition of inspect wait to inspect failed with event abort to ironic state machine.

REST API impact

Modify provision state API to support the transition described in this spec. API microversion will be bumped. For clients with earlier microversion, the verb abort is not allowed when a node is in inspect wait state.

• PUT /v1/nodes/{node_ident}/states/provision

  • The same JSON Schema is used to abort a node in inspecting state:

    {
      "target": "abort"
    }

  • For client with earlier microversion, 406 (Not Acceptable) is returned

  • For client with supported microversion

    • 202 (Accepted) is returned if request accepted
    • 400 (Bad Request) is returned if current inspect interface does not support abort

Client (CLI) impact

"ironic" CLI

None

"openstack baremetal" CLI

None

RPC API impact

None

Driver API impact

A new method abort will be added to InspectInterface in base.py, the default behavior is to raise the exception UnsupportedDriverExtension:

def abort(self, task):
    raise exception.UnsupportedDriverExtension(
        driver=task.node.inspect_interface,
        extension='abort')

Nova driver impact

None

Ramdisk impact

None

Security impact

None

Other end user impact

None

Scalability impact

For multiple nodes under inspection in a notable scale, it will reduce a little time costs in case of inspection retry.

Performance Impact

None

Other deployer impact

Deployers can abort hardware introspection through ironic API/CLI, besides the inspector API/CLI, for nodes using inspector as the (in-band) inspection interface.

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

kaifeng

Work Items

• Add transition of inspect wait to inspect failed via abort.
• Add a new method abort() to the base inspect interface.
• Add the abort implementation to ironic inspector.Inspector.
• Implement the abort logic in ironic conductor.

Dependencies

None

Testing

Tempest test will be added to test the REST API change.

Upgrades and Backwards Compatibility

API will be bumped for backward compatibility. Client requests with microversion before this feature will be treated identically.

Documentation Impact

Related documents and state machine diagram will be updated accordingly.

References

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1. https://specs.openstack.org/openstack/ironic-specs/specs/approved/inspect-wait-state.html↩︎