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Taikun OCP Guide

Table of Contents

Deploying with anaconda deploy interface

Ironic supports deploying an OS with the anaconda installer.
This anaconda deploy interface works with pxe and
ipxe boot interfaces.

Configuration

The anaconda deploy interface is not enabled by default. To enable
this, add anaconda to the value of the
enabled_deploy_interfaces configuration option in
ironic.conf. For example:

[DEFAULT]
...
enabled_deploy_interfaces = direct,anaconda
...

This change takes effect after all the ironic conductors have been
restarted.

The default kickstart template is specified via the configuration
option [anaconda]default_ks_template. It is set to this ks.cfg.template
but can be modified to be some other template.

[anaconda]
default_ks_template = file:///etc/ironic/ks.cfg.template

When creating an ironic node, specify anaconda as the
deploy interface. For example:

baremetal node create --driver ipmi \
    --deploy-interface anaconda \
    --boot-interface ipxe

You can also set the anaconda deploy interface via
--deploy-interface on an existing node:

baremetal node set <node> --deploy-interface anaconda

Creating an OS Image

While anaconda allows installing individual RPMs, the default
kickstart file expects an OS tarball to be used as the OS image.

This baremetal.yum file contains all the yum/dnf
commands that need to be run in order to generate the OS tarball. These
commands install packages and package groups that need to be in the
image:

group install 'Minimal Install'
install cloud-init
ts run

An OS tarball can be created using following set of commands, along
with the above baremetal.yum file:

export CHROOT=/home/<user>/os-image
mkdir -p $(CHROOT)
mkdir -p $(CHROOT)/{dev,proc,run,sys}
chown -hR root:root $(CHROOT)
mount --bind /var/cache/yum $(CHROOT)/var/cache/yum
mount --bind /dev $(CHROOT)/dev
mount -t proc proc $(CHROOT)/proc
mount -t tmpfs tmpfs $(CHROOT)/run
mount -t sysfs sysfs $(CHROOT)/sys
dnf -y --installroot=$(CHROOT) makecache
dnf -y --installroot=$(CHROOT) shell baremetal.yum
rpm --root $(CHROOT) --import $(CHROOT)/etc/pki/rpm-gpg/RPM-GPG-KEY-*
truncate -s 0 $(CHROOT)/etc/machine-id
umount $(CHROOT)/var/cache/yum
umount $(CHROOT)/dev
umount $(CHROOT)/proc
umount $(CHROOT)/run
umount $(CHROOT)/sys
tar cpzf os-image.tar.gz --xattrs --acls --selinux -C $(CHROOT) .

Configuring the OS Image in
glance

Anaconda is a two-stage installer — stage 1 consists of the kernel
and ramdisk and stage 2 lives in a squashfs file. All these components
can be found in the CentOS/RHEL/Fedora ISO images.

The kernel and ramdisk can be found at
/images/pxeboot/vmlinuz and
/images/pxeboot/initrd.img respectively in the ISO. The
stage 2 squashfs image can be normally found at
/LiveOS/squashfs.img or
/images/install.img.

The OS tarball must be configured with the following properties in
glance, in order to be used with the anaconda deploy driver:

  • kernel_id
  • ramdisk_id
  • stage2_id
  • disk_file_extension (optional)

Valid disk_file_extension values are .img,
.tar, .tbz, .tgz,
.txz, .tar.gz, .tar.bz2, and
.tar.xz. When disk_file_extension property is
not set to one of the above valid values the anaconda installer will
assume that the image provided is a mountable OS disk.

This is an example of adding the anaconda-related images and the OS
tarball to glance:

openstack image create --file ./vmlinuz --container-format aki \
    --disk-format aki --shared anaconda-kernel-<version>
openstack image create --file ./initrd.img --container-format ari \
    --disk-format ari --shared anaconda-ramdisk-<version>
openstack image create --file ./squashfs.img --container-format ari \
    --disk-format ari --shared anaconda-stage-<verison>
openstack image create --file ./os-image.tar.gz \
    --container-format bare --disk-format raw --shared \
    --property kernel_id=<glance_uuid_vmlinuz> \
    --property ramdisk_id=<glance_uuid_ramdisk> \
    --property stage2_id=<glance_uuid_stage2> disto-name-version \
    --property disk_file_extension=.tgz

Creating a bare metal server

Apart from uploading a custom kickstart template to glance and
associating it with the OS image via the ks_template
property in glance, operators can also set the kickstart template in the
ironic node’s instance_info field. The kickstart template
set in instance_info takes precedence over the one
specified via the OS image in glance. If no kickstart template is
specified (via the node’s instance_info or
ks_template glance image property), the default kickstart
template will be used to deploy the OS.

This is an example of how to set the kickstart template for a
specific ironic node:

openstack baremetal node set <node> \
    --instance_info ks_template=glance://uuid

Warning

In the Ironic Project terminology, the word template
often refers to a file which is supplied to the deployment, which Ironic
supplies parameters to render a specific output. One critical example of
this in the Ironic workflow, specifically with this driver, is that the
generated agent token is conveyed to the booting ramdisk,
facilitating it to call back to Ironic and indicate the state. This
token is randomly generated for every deploy, and is required.
Specifically this is leveraged in the template’s pre,
onerror, and post steps. For more infomation
on Agent Token, please see /admin/agent-token.

Standalone deployments

While this deployment interface driver was developed around the use
of other OpenStack services, it is not explicitly required. For example
HTTP(S) URLs can be supplied by the API user to explictly set the
expected baremetal node instance_info fields

baremetal node set <node> \
   --instance_info image_source=<Mirror URL> \
   --instance_info kernel=<Kernel URL> \
   --instance_info ramdisk=<Initial Ramdisk URL> \
   --instance_info stage2=<Installer Stage2 Ramdisk URL>

When doing so, you may wish to also utilize a customized kickstart
template, which can also be a URL. Please reference the ironic community
provided template ks.cfg.template and use it as a basis of your
own kickstart as it accounts for the particular stages and appropriate
callbacks to Ironic.

Warning

The default template (for the kickstart ‘liveimg’ command) expects an
instance_info\image_info setting to be provided by the
user, which serves as a base operating system image. In the context of
the anaconda driver, it should be thought of almost like “stage3”. If
you’re using a custom template, it may not be required, but proceed with
caution. See pykickstart
documentation
for more information on liveimg file format,
structure, and use.

baremetal node set <node> \
    --instance_info ks_template=<URL>

If you do choose to use a liveimg with a customized template, or if
you wish to use the stock template with a liveimg, you will need to
provide this setting.

baremetal node set <node> \
    --instance_info image_info=<URL>

Warning

This is required if you do not utilize a customised
template. As in use Ironic’s stock template.

The pattern of deployment in this case is identical to a deployment
case where Ironic is integrated with OpenStack, however in this case
Ironic collects the files, and stages them appropriately.

At this point, you should be able to request the baremetal node to
deploy.

Standalone using a
repository

Anaconda supports a concept of passing a repository as opposed to a
dedicated URL path which has a .treeinfo file, which tells
the initial boot scripts where to get various dependencies, such as what
would be used as the anaconda stage2 ramdisk.
Unfortunately, this functionality is not well documented.

An example .treeinfo file can be found at http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/.treeinfo.

Note

In the context of the .treeinfo file and the related
folder structure for a deployment utilizing the anaconda
deployment interface, images/install.img file represents a
stage2 ramdisk.

In the context of one wishing to deploy Centos Stream-9, the
following may be useful.

baremetal node set <node> \
    --instance_info image_source=http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/ \
    --instance_info kernel=http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/images/pxeboot/vmlinuz \
    --instance_info ramdisk=http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/images/pxeboot/initrd.img

Once set, a kickstart template can be provided via an
instance_info parameter, and the node deployed.

Deployment Process

At a high level, the mechanics of the anaconda driver works in the
following flow, where we also note the stages and purpose of each part
for informational purposes.

  1. Network Boot Program (Such as iPXE) downloads the kernel, and
    initial ramdisk.
  2. Kernel launches, uncompresses initial ramdisk, and executes init
    inside of the ramdisk.
  3. The initial ramdisk boot scripts, such as Dracut, recognize the
    kernel command line parameters Ironic supplied with the boot
    configuration, and downloads the second stage artifacts, in this case
    called the stage2 image. This image contains Anaconda and
    base dependencies.
  4. Anaconda downloads and parses the kickstart configuration which was
    also supplied on the kernel command line, and executes the commands as
    defined in the kickstart template.
  5. The kickstart template, if specified in its contents, downloads a
    liveimg which is used as the base operating system image to
    start with.

Limitations

This deploy interface has only been tested with Red Hat based
operating systems that use anaconda. Other systems are not
supported.

Runtime TLS certifiate injection into ramdisks is not supported.
Assets such as ramdisk or a stage2 ramdisk
image need to have trusted Certificate Authority certificates present
within the images or the Ironic API endpoint utilized should
utilize a known trusted Certificate Authority.

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