Partition image support for agent driver

This blueprint suggests to enhance agent driver to support deploy partition images with subsequent boot to happen over pxe or vmedia as specified by the driver.

Problem description

As of now agent driver support only whole disk images that can be deployed on the baremetal. With disk image based deploy, the subsequent boot will happen from the local hard drive. Ironic does not have control over the subsequent boots of the provisioned baremetal node.

Proposed change

  • Agent driver validate the specified image type is of partition image(raw) by looking for kernel_id and ramdisk_id image properties.

  • Send partition information(root, swap, etc) to the agent ramdisk through image_info.

  • Upon receiving the partition information, agent ramdisk will work on the given os_install disk and copy the partition image in the root partition.

  • Agent ramdisk sends back the root_uuid to the agent driver on the controller.

  • Post deploy, agent driver prepares the config for subsequent boot, either using pxe or vmedia as defined by the driver. Both agent_ipmitool and agent_ilo driver should support deploy with parition images.

  • Factor out the partitioning code from ironic into a different library and use it in both IPA and ironic code base.


We can use iscsi method to write partition image on to the target disk. We need agent ramdisk to support iscsi, similar to the ironic DIB element.

Data model impact


State Machine Impact


REST API impact


Client (CLI) impact


RPC API impact


Driver API impact


Nova driver impact


Ramdisk impact


Security impact


Other end user impact

Ability to deploy partition images on nodes managed by the agent.

Scalability impact


Performance Impact


Other deployer impact


Developer impact




Primary assignee:


Other contributors:


Work Items

  • Factor out the partitioning code from ironic into a common library for both IPA and ironic code base.

    1. Move the disk partition code from ironic/common to an oslo incubator project as oslo.libironic

      • ironic/common/

      • Some common disk related functions from ironic/drivers/modules/

      • Related test cases.

    2. Use oslo.libironic in IPA

  • Make necessary changes in agent driver common code, such as validate, deploy, etc.

  • Make necessary changes in agent_ipmitool driver to generate correct pxe config for subsequent reboot.

  • Make necessary changes in agent_ilo driver to generate iso for subsequent reboot.

  • Make changes in IPA (agent ramdisk) to recognize the incoming image information and take appropriate action to deploy partition image on the disk.



  • Unit testing with partition images with agent_ilo and agent_ipmitool drivers.

  • Add specific agent driver test cases with partition images in tempest/devstack.

Upgrades and Backwards Compatibility

Documentation Impact

  • Make changes to ironic install guide.