OSDOCS-1630 - RHCOS bootupd overview

[bobfuru]

OSDOCS-1630 (docs epic) tracking feature complete work for RHCOS bootupd in OCP 4.7, as described in GRPA-2895. The purpose of this PR is to include an overview of bootupd, and to determine whether additional task-based docs are required for RHCOS/OCP users.

PREVIEW LINKS
"Key RHCOS features":
https://osdocs-1630--ocpdocs.netlify.app/openshift-enterprise/latest/architecture/architecture-rhcos.html#rhcos-key-features_architecture-rhcos

Manual enable/machine config methods:
https://osdocs-1630--ocpdocs.netlify.app/openshift-enterprise/latest/architecture/architecture-rhcos.html#architecture-rhcos-updating-bootloader.adoc_architecture-rhcos

@cgwalters @ashcrow
This is a relatively new realm for me, so I've been reading up on https://github.com/coreos/bootupd/ and related discussions. I'm trying to determine whether a mention of bootupd in the "Key RHCOS features" list is sufficient, or if I should build this out as a larger section, possibly with commands.

From an OCP user's perspective, I have some open questions that I am seeking your input on:

• Is it enough to be telling users that bootupd is enabled by default? Anything else they need to do to enable bootupd?
• Assuming this runs in background, should we describe how often and when firmware and bootloader updates happen?
• Can a cluster admin perform any bootupd commands/updates via CLI? For example, borrowing from fwupd examples, are there commands that we want to document for bootupd? Such as:

The following commands allow you to check for updates on a device with firmware supported by bootupd.

To display all devices detected by bootupd:
# bootupd get-devices

To download the latest metadata from bootupd:
# bootupd refresh

To see if you have updates available for any devices on the system:
#bootupd get-updates

To download and apply all updates for your system:
# bootupd update

Any feedback is greatly appreciated, thanks!

[openshift-docs-preview-bot]

The preview will be available shortly at:

• https://OSDOCS-1630--ocpdocs.netlify.com/

[ashcrow]

From an OCP user's perspective, I have some open questions that I am seeking your input on:

* Is it enough to be telling users that bootupd is enabled by default? Anything else they need to do to enable bootupd?

* Assuming this runs in background, should we describe how often and when firmware and bootloader updates happen?

My $0.02 is that we should not as it is meant to run with OCP update process. Noting it's new and enabled in 4.7 should be enough IMHO.

* Can a cluster admin perform any bootupd commands/updates via CLI? For example, borrowing from [fwupd](https://github.com/fwupd/fwupd/) examples, are there commands that we want to document for bootupd? Such as:

Can they? Yes. Should they? Probably not. It should be done as part of the OCP update process. Similar to how one could run rpm-ostree commands on the host but they generally should let the product handle it.

However, pointing over to the bootupd project for folks to learn more would be nice for those interested.

@cgwalters Your thoughts?

[cgwalters]

My $0.02 is that we should not as it is meant to run with OCP update process.

Well we...aren't doing that right now by default. Lots of discussion in coreos/bootupd#8 and coreos/fedora-coreos-docs#203

(And ideally I was hoping that we could keep FCOS/RHCOS in sync regarding this - the FCOS docs PR hasn't merged because the latest bootupd isn't in FCOS stable because of coreos/fedora-coreos-tracker#649 )

I think basically for 4.7 (same as FCOS) we are just saying this is something one can run manually for now, or provide a MachineConfig with the simple systemd unit. And note that we may automate it in the future.

[bobfuru]

Thanks for the comments, @cgwalters. I wasn't aware of coreos/fedora-coreos-docs#2. I'll take that and the other conversation into consideration and figure out how to get this PR updated.

[bobfuru]

However, pointing over to the bootupd project for folks to learn more would be nice for those interested.

I'd like to avoid the upstream docs as there are likely to be parity and maintenance issues between the 2 sets.

I think basically for 4.7 (same as FCOS) we are just saying this is something one can run manually for now, or provide a MachineConfig with the simple systemd unit. And note that we may automate it in the future.

I've made a few revisions so that we have a general overview in the "Key RHCOS features" section, plus steps for how to enable bootupd via bootctl or machine config later on in the same page but as a distinct module taken from the FCOS docs PR (coreos/fedora-coreos-docs#203).

I'd also like to avoid making statements that predict future availability.

[bobfuru]

@cgwalters and @ashcrow - I'd like your feedback on the manual install/MachineConfig instructions I've added. Not sure if you had it in mind that we should include that level of detail or not. Thanks.

[bobfuru]

@cgwalters and @ashcrow - Bump, PTAL and let me know if you have any additional feedback or if this looks good to you.
Preview here

[bobfuru]

@openshift/team-documentation PTAL

[bobfuru]

/cherrypick enterprise-4.7

[openshift-cherrypick-robot]

@bobfuru: new pull request created: #28658

In response to this:

/cherrypick enterprise-4.7

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