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Hardware introspection for OpenStack Ironic

Project description


ironic-discoverd project was renamed to ironic-inspector and its new home is at Some links are already pointing at the new location in this document.

ironic-discoverd 1.1 branch will only receive critical bug fixes, other branches are not supported at all. Please switch to ironic-inspector as soon as time allows.

This is an auxiliary service for discovering hardware properties for a node managed by OpenStack Ironic. Hardware introspection or hardware properties discovery is a process of getting hardware parameters required for scheduling from a bare metal node, given it’s power management credentials (e.g. IPMI address, user name and password).

A special discovery ramdisk is required to collect the information on a node. The default one can be built using diskimage-builder and ironic-discoverd-ramdisk element (see Configuration below).

Support for ironic-discoverd is present in Tuskar UI – OpenStack Horizon plugin for TripleO.

ironic-discoverd requires OpenStack Juno (2014.2) release or newer.

Please use launchpad to report bugs and ask questions. Use PyPI for downloads and accessing the released version of this README.

Please contribute to the renamed ironic-inspector project - see CONTRIBUTING.rst for details.


Usual hardware introspection flow is as follows:

  • Operator installs undercloud with ironic-discoverd (e.g. using instack-undercloud).

  • Operator enrolls nodes into Ironic either manually or by uploading CSV file to Tuskar UI. Power management credentials should be provided to Ironic at this step.

  • Nodes are put in the correct state for introspection as described in Node States.

  • Operator sends nodes on introspection either manually using ironic-discoverd API (see Usage) or again via Tuskar UI.

  • On receiving node UUID ironic-discoverd:

    • validates node power credentials, current power and provisioning states,
    • allows firewall access to PXE boot service for the nodes,
    • issues reboot command for the nodes, so that they boot the discovery ramdisk.
  • The discovery ramdisk collects the required information and posts it back to ironic-discoverd.

  • On receiving data from the discovery ramdisk, ironic-discoverd:

    • validates received data,
    • finds the node in Ironic database using it’s BMC address (MAC address in case of SSH driver),
    • fills missing node properties with received data and creates missing ports.


    ironic-discoverd is responsible to create Ironic ports for some or all NIC’s found on the node. ironic-discoverd is also capable of deleting ports that should not be present. There are two important configuration options that affect this behavior: add_ports and keep_ports (please refer to example.conf for detailed explanation).

    Default values as of ironic-discoverd 1.1.0 are add_ports=pxe, keep_ports=all, which means that only one port will be added, which is associated with NIC the ramdisk PXE booted from. No ports will be deleted. This setting ensures that deploying on introspected nodes will succeed despite Ironic bug 1405131.

    Ironic inspection feature by default requires different settings: add_ports=all, keep_ports=present, which means that ports will be created for all detected NIC’s, and all other ports will be deleted. Refer to the Ironic inspection documentation for details.

  • Separate API (see Usage) can be used to query introspection results for a given node.

  • Nodes are put in the correct state for deploying as described in Node States.

Starting DHCP server and configuring PXE boot environment is not part of this package and should be done separately.


ironic-discoverd is available as an RPM from Fedora 22 repositories or from Juno (and later) RDO for Fedora 20, 21 and EPEL 7. It will be installed and preconfigured if you used instack-undercloud to build your undercloud. Otherwise after enabling required repositories install it using:

yum install openstack-ironic-discoverd

To install only Python packages (including the client), use:

yum install python-ironic-discoverd

Alternatively (e.g. if you need the latest version), you can install package from PyPI (you may want to use virtualenv to isolate your environment):

pip install ironic-discoverd


Copy example.conf to some permanent place (/etc/ironic-discoverd/discoverd.conf is what is used in the RPM). Fill in at least these configuration values:

  • os_username, os_password, os_tenant_name - Keystone credentials to use when accessing other services and check client authentication tokens;
  • os_auth_url, identity_uri - Keystone endpoints for validating authentication tokens and checking user roles;
  • database - where you want ironic-discoverd SQLite database to be placed;
  • dnsmasq_interface - interface on which dnsmasq (or another DHCP service) listens for PXE boot requests (defaults to br-ctlplane which is a sane default for TripleO based installations but is unlikely to work for other cases).

See comments inside example.conf for the other possible configuration options.


Configuration file contains a password and thus should be owned by root and should have access rights like 0600.

As for PXE boot environment, you’ll need:

  • TFTP server running and accessible (see below for using dnsmasq). Ensure pxelinux.0 is present in the TFTP root.

  • Build and put into your TFTP directory kernel and ramdisk from the diskimage-builder ironic-discoverd-ramdisk element:

    ramdisk-image-create -o discovery fedora ironic-discoverd-ramdisk

    You need diskimage-builder 0.1.38 or newer to do it (using the latest one is always advised).

  • You need PXE boot server (e.g. dnsmasq) running on the same machine as ironic-discoverd. Don’t do any firewall configuration: ironic-discoverd will handle it for you. In ironic-discoverd configuration file set dnsmasq_interface to the interface your PXE boot server listens on. Here is an example dnsmasq.conf:

    dhcp-range={DHCP IP RANGE, e.g.,}
    tftp-root={TFTP ROOT, e.g. /tftpboot}
  • Configure your $TFTPROOT/pxelinux.cfg/default with something like:

    default discover
    label discover
    kernel discovery.kernel
    append initrd=discovery.initramfs discoverd_callback_url=http://{IP}:5050/v1/continue
    ipappend 3

    Replace {IP} with IP of the machine (do not use loopback interface, it will be accessed by ramdisk on a booting machine).


    There are some prebuilt images which use obsolete ironic_callback_url instead of discoverd_callback_url. Modify pxelinux.cfg/default accordingly if you have one of these.

Here is discoverd.conf you may end up with:

debug = false
identity_uri =
os_auth_url =
os_username = admin
os_password = password
os_tenant_name = admin
dnsmasq_interface = br-ctlplane


Set debug = true if you want to see complete logs.


If you installed ironic-discoverd from the RPM, you already have a systemd unit, so you can:

systemctl enable openstack-ironic-discoverd
systemctl start openstack-ironic-discoverd

Otherwise run as root:

ironic-discoverd --config-file /etc/ironic-discoverd/discoverd.conf


Running as root is not required if ironic-discoverd does not manage the firewall (i.e. manage_firewall is set to false in the configuration file).

A good starting point for writing your own systemd unit should be one used in Fedora.


ironic-discoverd has a simple client library for Python and a CLI tool bundled with it.

Client library is in module ironic_discoverd.client, every call accepts additional optional arguments:

  • base_url ironic-discoverd API endpoint, defaults to,
  • auth_token Keystone authentication token.

CLI tool is based on OpenStackClient with prefix openstack baremetal introspection. Accepts optional argument --discoverd-url with the ironic-discoverd API endpoint.

  • Start introspection on a node:

    introspect(uuid, new_ipmi_username=None, new_ipmi_password=None)

    $ openstack baremetal introspection start UUID [--new-ipmi-password=PWD [--new-ipmi-username=USER]]
    • uuid - Ironic node UUID;
    • new_ipmi_username and new_ipmi_password - if these are set, ironic-discoverd will switch to manual power on and assigning IPMI credentials on introspection. See Setting IPMI Credentials for details.
  • Query introspection status:


    $ openstack baremetal introspection status UUID
    • uuid - Ironic node UUID.

Refer to HTTP-API.rst for information on the HTTP API.

Using from Ironic API

Ironic Kilo introduced support for hardware introspection under name of “inspection”. ironic-discoverd introspection is supported for some generic drivers, please refer to Ironic inspection documentation for details.

Node States

  • As of Ironic Kilo release the nodes should be moved to MANAGEABLE provision state before introspection (requires python-ironicclient of version 0.5.0 or newer):

    ironic node-set-provision-state <UUID> manage

    With Juno release and/or older python-ironicclient it’s recommended to set maintenance mode, so that nodes are not taken by Nova for deploying:

    ironic node-update <UUID> replace maintenance=true
  • After successful introspection and before deploying nodes should be made available to Nova, either by moving them to AVAILABLE state (Kilo):

    ironic node-set-provision-state <UUID> provide

    or by removing maintenance mode (Juno and/or older client):

    ironic node-update <UUID> replace maintenance=false


    Due to how Nova interacts with Ironic driver, you should wait 1 minute before Nova becomes aware of available nodes after issuing these commands.

Setting IPMI Credentials

If you have physical access to your nodes, you can use ironic-discoverd to set IPMI credentials for them without knowing the original ones. The workflow is as follows:

  • Ensure nodes will PXE boot on the right network by default.
  • Set enable_setting_ipmi_credentials = true in the ironic-discoverd configuration file.
  • Enroll nodes in Ironic with setting their ipmi_address only. This step allows ironic-discoverd to distinguish nodes.
  • Set maintenance mode on nodes. That’s an important step, otherwise Ironic might interfere with introspection process.
  • Start introspection with providing additional parameters:
    • new_ipmi_password IPMI password to set,
    • new_ipmi_username IPMI user name to set, defaults to one in node driver_info.
  • Manually power on the nodes and wait.
  • After introspection is finished (watch nodes power state or use ironic-discoverd status API) you can turn maintenance mode off.

Note that due to various limitations on password value in different BMC, ironic-discoverd will only accept passwords with length between 1 and 20 consisting only of letters and numbers.


ironic-discoverd heavily relies on plugins for data processing. Even the standard functionality is largely based on plugins. Set processing_hooks option in the configuration file to change the set of plugins to be run on introspection data. Note that order does matter in this option.

These are plugins that are enabled by default and should not be disabled, unless you understand what you’re doing:

reports error, if error field is set by the ramdisk, also optionally stores logs from logs field, see HTTP API for details.
validates and updates basic hardware scheduling properties: CPU number and architecture, memory and disk size.
validates network interfaces information.

Here are some plugins that can be additionally enabled:

example plugin logging it’s input and output.
gathers block devices from ramdisk and exposes root device in multiple runs.

Refer to CONTRIBUTING.rst for information on how to write your own plugin.


Errors when starting introspection

  • Refusing to introspect node <UUID> with provision state “available” and maintenance mode off

    In Kilo release with python-ironicclient 0.5.0 or newer Ironic defaults to reporting provision state AVAILABLE for newly enrolled nodes. ironic-discoverd will refuse to conduct introspection in this state, as such nodes are supposed to be used by Nova for scheduling. See Node States for instructions on how to put nodes into the correct state.

Introspection times out

There may be 3 reasons why introspection can time out after some time (defaulting to 60 minutes, altered by timeout configuration option):

  1. Fatal failure in processing chain before node was found in the local cache. See Troubleshooting data processing for the hints.
  2. Failure to load discovery ramdisk on the target node. See Troubleshooting PXE boot for the hints.
  3. Failure during ramdisk run. See Troubleshooting ramdisk run for the hints.

Troubleshooting data processing

In this case ironic-discoverd logs should give a good idea what went wrong. E.g. for RDO or Fedora the following command will output the full log:

sudo journalctl -u openstack-ironic-discoverd


Service name and specific command might be different for other Linux distributions.

If ramdisk_error plugin is enabled and ramdisk_logs_dir configuration option is set, ironic-discoverd will store logs received from the ramdisk to the ramdisk_logs_dir directory. This depends, however, on the ramdisk implementation.

Troubleshooting PXE boot

PXE booting most often becomes a problem for bare metal environments with several physical networks. If the hardware vendor provides a remote console (e.g. iDRAC for DELL), use it to connect to the machine and see what is going on. You may need to restart introspection.

Another source of information is DHCP and TFTP server logs. Their location depends on how the servers were installed and run. For RDO or Fedora use:

$ sudo journalctl -u openstack-ironic-discoverd-dnsmasq

The last resort is tcpdump utility. Use something like

$ sudo tcpdump -i any port 67 or port 68 or port 69

to watch both DHCP and TFTP traffic going through your machine. Replace any with a specific network interface to check that DHCP and TFTP requests really reach it.

If you see node not attempting PXE boot or attempting PXE boot on the wrong network, reboot the machine into BIOS settings and make sure that only one relevant NIC is allowed to PXE boot.

If you see node attempting PXE boot using the correct NIC but failing, make sure that:

  1. network switches configuration does not prevent PXE boot requests from propagating,
  2. there is no additional firewall rules preventing access to port 67 on the machine where ironic-discoverd and its DHCP server are installed.

If you see node receiving DHCP address and then failing to get kernel and/or ramdisk or to boot them, make sure that:

  1. TFTP server is running and accessible (use tftp utility to verify),
  2. no firewall rules prevent access to TFTP port,
  3. DHCP server is correctly set to point to the TFTP server,
  4. pxelinux.cfg/default within TFTP root contains correct reference to the kernel and ramdisk.

Troubleshooting ramdisk run

Connect to the remote console as described in Troubleshooting PXE boot to see what is going on with the ramdisk. The ramdisk drops into emergency shell on failure, which you can use to look around. There should be file called logs with the current ramdisk logs.

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