[RFE] Support multi arch deployments

[Yibo Cai]

Depending on BIOS or UEFI node property, Ironic selects boot file based on "pxe_bootfile_name" and "uefi_pxe_bootfile_name" options. For each option, only one value can be set. For example, "uefi_pxe_bootfile_name = bootx64.efi" to deploy x86_64 nodes.

To deploy other architecture, say AArch64, we have to change the setting to something like "uefi_pxe_bootfile_name = grubaa64.efi". After that, this Ironic conductor can only deploy AArch64 nodes, not x86_64.

Some bare metal provisioning tools, like MaaS, support multi arch deployment by one server. I wonder if Ironic could also support it.

Proposal:
- Introduce two new dictionary options: "pxe_bootfile_name_by_arch" and "pxe_config_template_by_arch".
- "pxe_bootfile_name_by_arch" preempts "pxe_bootfile_name" and "uefi_pxe_bootfile_name" if node's cpu_arch is found in the dictionary.
- E.g. pxe_bootfile_name_by_arch = aarch64:grubaa64.efi,ppc64:bootppc64.bin
  * For x86_64 nodes, original "pxe_bootfile_name" and "uefi_pxe_bootfile_name" are used as usual.
  * For aarch64 nodes, boot file will be grubaa64.efi.
- Same rule for "pxe_config_template_by_arch".

[Lucas Alvares Gomes (lucasagomes)]

Before approving, can you give a more realistic example of how the pxe_bootfile_names will look like?

Your example:

pxe_bootfile_names = "def-filename" "arch2:filename2" "arch3:filename3"

Where's the boot mode (bios vs uefi) there?

...

Also, how do we handle backward compatibility with old options? Check if "pxe_bootfile_names" is set, if so use it, if not use the old pxe_bootfile_name/uefi_pxe_bootfile_name ?

[Yibo Cai (cyb70289)]

About "bios/uefi boot mode encoding"
====================================

In statement: pxe_bootfile_name = "def-filename" "arch2:filename2" "arch3:filename3".
"arch2","arch3" are not "x86","aarch64", but client-arch code from RFC4578(https://tools.ietf.org/html/rfc4578). The client-arch code contains both arch and boot mode information, as follows:
(copied from RFC4578)
Type Architecture Name
---- -----------------
0 Intel x86PC (BIOS)
...
6 EFI IA32
...
9 EFI x86-64
B EFI AArch64
C PowerPC64

The final statement looks like:
pxe_bootfile_name = pxelinux.0 09:bootx64.efi 0B:grubaa64.efi 0C:bootppc64.bin

About "backward compatibility"
==============================

Rather than introducing a new parameter, maybe we can extend current "pxe_bootfile_name". Its default value is still only "pxelinux.0". Arch specific extensions can be appended like upper example. Internal representation becomes a dictionary.

Add an optional property "pxe_client_arch" to Ironic node. If the node needs a arch specific bootfile, it can set this property to match arch in pxe_bootfile_name extensions.

"uefi_pxe_bootfile_name" is kept, which is "default bootfile for uefi node without pxe_client_arch specified".

By this way, looks current deployment and configurations won't be affected.

About boot template file
========================

"pxe_config_template" parameter should also be extended this way.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/322632

[Yibo Cai (cyb70289)]

Current code logic:

- Two new dictionary options are introduced: "pxe_bootfile_name_by_arch" and "pxe_config_template_by_arch".
- "pxe_bootfile_name_by_arch" preempts 'pxe_bootfile_name' and 'uefi_pxe_bootfile_name' if node's cpu_arch is found in the dictionary value.
- E.g. pxe_bootfile_name_by_arch = aarch64:grubaa64.efi,ppc64:bootppc64.bin
  * For x86/x86_64 nodes, original 'pxe_bootfile_name' and 'uefi_pxe_bootfile_name' are used as usual.
  * For aarch64 nodes, boot file will be grubaa64.efi.
- Same rule for "pxe_config_template_by_arch".

[Yibo Cai (cyb70289)]

Hi Lucas,

Would you have a look at current code and above comment? If it's okay, please help approving this rfe. Thanks.

BR,
Yibo

[Lucas Alvares Gomes (lucasagomes)]

Hi Yibo,

Sorry for the delay on this. Yes I like the last code logic (comment #4)!

[Lucas Alvares Gomes (lucasagomes)]

Btw, can you please update the bug description with the current proposed design ?

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/322632
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=f8ff1b26beb7c386429d1ddb2f869a225cc71d8d
Submitter: Jenkins
Branch: master

commit f8ff1b26beb7c386429d1ddb2f869a225cc71d8d
Author: Yibo Cai <email address hidden>
Date: Mon May 23 17:58:28 2016 +0800

    Support multi arch deployment

    Ironic is flexible for x86/x86_64 servers by supporting BIOS and UEFI.
    But to deploy servers of other architectures, such as aarch64 or ppc64,
    configuration(PXE boot file and config template) must be modified,
    which means one Ironic conductor can only deploy baremetal machines of
    one architecture.

    This patch adds multi arch deployment support. For example, to deploy
    x86_64 and aarch64 servers by one Ironic conductor.

    Closes-Bug: #1582964

    Change-Id: I628320aeb44b232a262d0843bc726a68d297e1f8

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/386313

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/386313
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=168d48eb76fdd39872f57b61f2d0e4e857ffd219
Submitter: Jenkins
Branch: master

commit 168d48eb76fdd39872f57b61f2d0e4e857ffd219
Author: Ruby Loo <email address hidden>
Date: Thu Oct 13 22:57:00 2016 -0400

    Update guide for PXE multi-architecture setup

    This updates documentation for PXE multi-architecture setup in
    the install guide. It clarifies the values for the two *_arch
    config options and combines the two examples into one.

    Change-Id: I10684e16dd6efcc6d17fb4a825e55286c16a20be
    Related-Bug: #1582964

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ironic 7.0.0 release.