Add documentation for ISO boot

Split ramdisk deploy information away from other deploy interfaces,
since it's so different from the other interfaces (and to highlight
it in the top-level index).

Change-Id: Id3a5d71141451a45e89ffdba903966bb7da84d55
This commit is contained in:
Dmitry Tantsur 2020-09-24 14:25:25 +02:00
parent 28c0f38322
commit 8d8d9de90c
3 changed files with 83 additions and 42 deletions

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@ -30,6 +30,7 @@ the services.
Power Sync with the Compute Service <power-sync>
Node Multi-Tenancy <node-multitenancy>
Fast-Track Deployment <fast-track>
Booting a Ramdisk or an ISO <ramdisk-boot>
Advanced Topics
---------------

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@ -145,45 +145,5 @@ Ramdisk deploy
==============
The ramdisk interface is intended to provide a mechanism to "deploy" an
instance where the item to be deployed is in reality a ramdisk.
Most commonly this is performed when an instance is booted via PXE, iPXE or
Virtual Media, with the only local storage contents being those in memory.
It is suported by ``pxe`` and ``ilo-virtual-media`` boot interfaces.
As with most non-default interfaces, it must be enabled and set for a node
to be utilized:
.. code-block:: ini
[DEFAULT]
...
enabled_deploy_interfaces = iscsi,direct,ramdisk
...
Once enabled and the conductor(s) have been restarted, the interface can
be set upon creation of a new node or update a pre-existing node:
.. code-block:: shell
openstack baremetal node create --driver ipmi \
--deploy-interface ramdisk \
--boot-interface pxe
openstack baremetal node set <NODE> --deploy-interface ramdisk
The intended use case is for advanced scientific and ephemeral workloads
where the step of writing an image to the local storage is not required
or desired. As such, this interface does come with several caveats:
* Configuration drives are not supported.
* Disk image contents are not written to the bare metal node.
* Users and Operators who intend to leverage this interface should
expect to leverage a metadata service, custom ramdisk images, or the
``instance_info/ramdisk_kernel_arguments`` parameter to add options to
the kernel boot command line.
* Bare metal nodes must continue to have network access to PXE and iPXE
network resources. This is contrary to most tenant networking enabled
configurations where this access is restricted to the provisioning and
cleaning networks
* As with all deployment interfaces, automatic cleaning of the node will
still occur with the contents of any local storage being wiped between
deployments.
instance where the item to be deployed is in reality a ramdisk. It is
documented separately, see :doc:`/admin/ramdisk-boot`.

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@ -0,0 +1,80 @@
Booting a Ramdisk or an ISO
===========================
Ironic supports booting a user provided ramdisk or an ISO image (starting with
the Victoria release) instead of deploying a node.
Most commonly this is performed when an instance is booted via PXE, iPXE or
Virtual Media, with the only local storage contents being those in memory.
It is suported by ``pxe``, ``ipxe``, ``redfish-virtual-media`` and
``ilo-virtual-media`` boot interfaces.
Configuration
-------------
Ramdisk/ISO boot requires using the ``ramdisk`` deploy interface. As with most
non-default interfaces, it must be enabled and set for a node to be utilized:
.. code-block:: ini
[DEFAULT]
...
enabled_deploy_interfaces = iscsi,direct,ramdisk
...
Once enabled and the conductor(s) have been restarted, the interface can
be set upon creation of a new node:
.. code-block:: shell
openstack baremetal node create --driver ipmi \
--deploy-interface ramdisk \
--boot-interface ipxe
or update an existing node:
.. code-block:: shell
openstack baremetal node set <NODE> --deploy-interface ramdisk
Using virtual media:
.. code-block:: shell
openstack baremetal node create --driver redfish \
--deploy-interface ramdisk \
--boot-interface redfish-virtual-media
.. TODO(dtantsur): document how exactly to create and boot a ramdisk
Booting an ISO
--------------
The ``ramdisk`` deploy interface can also be used to boot an ISO image.
For example,
.. code-block:: shell
openstack baremetal node set <NODE> \
--instance-info boot_iso=http://path/to/boot.iso
openstack baremetal node deploy <NODE>
Limitations
-----------
The intended use case is for advanced scientific and ephemeral workloads
where the step of writing an image to the local storage is not required
or desired. As such, this interface does come with several caveats:
* Configuration drives are not supported.
* Disk image contents are not written to the bare metal node.
* Users and Operators who intend to leverage this interface should
expect to leverage a metadata service, custom ramdisk images, or the
``instance_info/ramdisk_kernel_arguments`` parameter to add options to
the kernel boot command line.
* When using PXE/iPXE boot, bare metal nodes must continue to have network
access to PXE and iPXE network resources. This is contrary to most tenant
networking enabled configurations where this access is restricted to
the provisioning and cleaning networks
* As with all deployment interfaces, automatic cleaning of the node will
still occur with the contents of any local storage being wiped between
deployments.