ironic-specs/specs/approved/iscsi-deploy-in-band-cleaning.rst

In-band cleaning support in iSCSI deploy drivers

https://bugs.launchpad.net/ironic/+bug/1526405

Current deploy drivers that make use of iSCSI don't support in-band cleaning. We need to make these drivers support in-band cleaning operations as well.

Problem description

Drivers that do iSCSI based deployment don't support in-band cleaning today. Hence in-band cleaning steps like disk erase, in-band RAID configuration, etc cannot be performed on these nodes which are registered with these drivers.

The following drivers (omitting the testing drivers) do iSCSI based deployment today:

• pxe{ipmitool,ipminative,seamicro,iboot,ilo,

  drac,snmp,irmc,amt,msftocs,ucs,wol}

• iscsi_ilo
• iscsi_irmc

Proposed change

• Deprecate the opt CONF.agent.agent_erase_devices_priority and move that to CONF.deploy.agent_erase_devices_priority.
• Add the following methods to iscsi_deploy.ISCSIDeploy (these methods will do the same things as what AgentDeploy does today)

  • prepare_cleaning - This method will create the Neutron cleaning ports for each of the Ironic ports and will call self.boot to prepare for booting the ramdisk and return states.CLEANWAIT. The method definition will be as follows:

    def prepare_cleaning(self, task):
        """Boot into the agent to prepare for cleaning.
    
        :param task: a TaskManager object containing the node
        :raises NodeCleaningFailure: if the previous cleaning ports cannot
            be removed or if new cleaning ports cannot be created
        :returns: states.CLEANWAIT to signify an asynchronous prepare
        """

  • tear_down_cleaning - This method will delete the cleaning ports created for the Ironic ports and will call self.boot to clean up the ramdisk boot. It will return None. The method definition will be as follows:

    def tear_down_cleaning(self, task):
        """Cleans up the environment after cleaning.
    
        :param task: a TaskManager object containing the node
        :raises NodeCleaningFailure: if the cleaning ports cannot be
            removed
        """

  • execute_clean_step - This method will call deploy_utils.agent_execute_clean_step. The method definition will be as follows:

    def execute_clean_step(self, task, step):
        """Execute a clean step asynchronously on the agent.
    
        :param task: a TaskManager object containing the node
        :param step: a clean step dictionary to execute
        :raises: NodeCleaningFailure if the agent does not return a command
            status
        :returns: states.CLEANWAIT to signify the step will be completed
            async
        """

  • get_clean_steps - This method will call deploy_utils.agent_get_clean_steps to get the cleaning steps from the agent ramdisk. It will also reassign the cleaning priority to disk erase.

    This will return an empty list if bash ramdisk is used. It will be detected by checking if agent_url is present in node's driver_internal_info.

    The method definition will be as follows:

    def get_clean_steps(self, task):
        """Get the list of clean steps from the agent.
    
        :param task: a TaskManager object containing the node
        :returns: A list of clean step dictionaries. Returns an
            empty list if bash ramdisk is used.
    """

• For deployers who have been using DIB ramdisk, the node will be stuck i n states.CLEANWAIT when they try to do cleaning. This is because DIB ramdisk doesn't heartbeat like agent ramdisk. Hence, such deployers might face the issue with nodes moving to states.CLEANFAIL as node enters cleaning. To overcome this problem, the following will be done:
  • Send the bash ramdisk parameters (deploy_key, iscsi_target_iqn, etc) while booting the deploy ramdisk for cleaning. It will enable bash ramdisk to invoke pass_deploy_info vendor passthru.
  • If node is in CLEANWAIT in pass_deploy_info vendor passthru, then we set the clean steps for the node and ask conductor to resume cleaning.
  • We also skip validation for pass_deploy_info vendor passthru if node is in CLEANWAIT state.

Alternatives

None.

Data model impact

None.

State Machine Impact

None.

REST API impact

None.

Client (CLI) impact

None.

RPC API impact

None.

Driver API impact

None.

Nova driver impact

None.

Ramdisk impact

N/A

Security impact

Drivers using iscsi_deploy.ISCSIDeploy will do in-band disk erase which will be a security benifit for tenants.

Other end user impact

None.

Scalability impact

None.

Performance Impact

None.

Other deployer impact

None.

Developer impact

None.

Implementation

Assignee(s)

Primary assignee:

rameshg87

Work Items

• Add new methods the iscsi_deploy.ISCSIDeploy for in-band cleaning.
• Modify pass_deploy_info to make it ready when it is invoked during cleaning.

Dependencies

• Completion of work for deploy-boot interface separation [2] to enable in-band cleaning for all drivers.

Testing

Unit tests will be added.

Upgrades and Backwards Compatibility

None.

Documentation Impact

The new CONF option and it's impact will be documented.

References

[1] http://specs.openstack.org/openstack/ironic-specs/specs/approved/deprecate-bash-ramdisk.html [2] https://blueprints.launchpad.net/ironic/+spec/new-boot-interface