make custom-first-boot script to work on bootc

[mrguitar]

1. this is putting the cart before the horse big time and is maybe the lowest priority ever.

2. this may be a dumb idea :)

Anyway, I took the first boot unit file from Terry's blog here: https://www.redhat.com/en/blog/first-boot-scripts-with-Insights-image-builder

This line will fail on a bootc system where /usr is RO. ExecStartPost=mv /usr/local/sbin/custom-first-boot /usr/local/sbin/custom-first-boot.done

I combined your unit file w/ the FCOS example and I think something like this might work better across both rpm & bootc installs. We're clearly a ways away from hitting this with bootc images, but I thought I'd call this out now since I just ran into it.
...just an idea.

[Unit]
Description=Run first boot script
Wants=network-online.target
After=network-online.target
ConditionPathExists=!/var/lib/firstboot

[Service]
Type=oneshot
ExecStart=/usr/local/sbin/custom-first-boot
ExecStartPost=/usr/bin/touch /var/lib/firstboot
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

[ezr-ondrej]

@lzap @amirfefer sounds like an easy change to do, right? 🤔

[lzap]

Nice catch, indeed this is a problem and your solution is something we can easily adopt. Let’s discuss the condition file location tho, looks like /var/lib has no files on my Fedora system. Is this a good place? Since this systemd unit is not part of any RPM file, I suggest /var/local. To prevent cluttering the directory perhaps even hidden file:

ConditionPathExists=!/var/local/.firstboot

ExecStartPost=/usr/bin/touch /var/local/.firstboot
RemainAfterExit=yes

@amirfefer I tried to find where the constant is stored in the frontend repo but could not find it at all :-) I could do this patch perhaps but unable to locate the code...

[amirfefer]

Thanks @mrguitar, nice catch 👍
@lzap, the constant is FIRST_BOOT_SERVICE_DATA in src/constants.ts, it's already base64 encoded.

I wonder though, would we use the same first boot customization on bootc images? Users can customize and run whatever they wish for in the Containerfile, no?

[ezr-ondrej]

Something might make sense to run as a firstboot script anyway tho (registration to domain/monitoring tool is a good example).

[lzap]

Yeah not everything you can bake into an image. Firstboot is still a useful feature for bootc. Lemme do a quick PR.

[lzap]

PR: osbuild/image-builder-frontend#2473