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Taikun OCP Guide

Table of Contents

Conductor Groups

Overview

Large scale operators tend to have needs that involve creating well
defined and delinated resources. In some cases, these systems may reside
close by or in far away locations. Reasoning may be simple or complex,
and yet is only known to the deployer and operator of the
infrastructure.

A common case is the need for delineated high availability domains
where it would be much more efficient to manage a datacenter in
Antarctica with a conductor in Antarctica, as opposed to a conductor in
New York City.

How it works

Starting in ironic 11.1, each node has a conductor_group
field which influences how the ironic conductor calculates (and thus
allocates) baremetal nodes under ironic’s management. This calculation
is performed independently by each operating conductor and as such if a
conductor has a [conductor]conductor_group configuration
option defined in its ironic.conf
configuration file, the conductor will then be limited to only managing
nodes with a matching conductor_group string.

Note

Any conductor without a [conductor]conductor_group
setting will only manage baremetal nodes without a
conductor_group value set upon node creation. If no such
conductor is present when conductor groups are configured, node creation
will fail unless a conductor_group is specified upon node
creation.

Warning

Nodes without a conductor_group setting can only be
managed when a conductor exists that does not have a
[conductor]conductor_group defined. If all conductors have
been migrated to use a conductor group, such nodes are effectively
“orphaned”.

How to use

A conductor group value may be any case insensitive string up to 255
characters long which matches the ^[a-zA-Z0-9_\-\.]*$
regular expression.

  1. Set the [conductor]conductor_group option in
    ironic.conf on one or more, but not all conductors:

    [conductor]
    conductor_group = OperatorDefinedString
  2. Restart the ironic-conductor service.

  3. Set the conductor group on one or more nodes:

    baremetal node set \
        --conductor-group "OperatorDefinedString" <uuid>
  4. As desired and as needed, remaining conductors can be updated
    with the first two steps. Please be mindful of the constraints covered
    earlier in the document related to ability to manage nodes.