cloud-init: unify `bootcmd` into `per-boot` script?

[AkihiroSuda]

lima/pkg/cidata/cidata.TEMPLATE.d/user-data

Lines 42 to 97 in 01b80e7

	write_files:
	- content: |
	#!/bin/sh
	set -eux
	LIMA_CIDATA_MNT="/mnt/lima-cidata"
	LIMA_CIDATA_DEV="/dev/disk/by-label/cidata"
	mkdir -p -m 700 "${LIMA_CIDATA_MNT}"
	mount -o ro,mode=0700,dmode=0700,overriderockperm,exec,uid=0 "${LIMA_CIDATA_DEV}" "${LIMA_CIDATA_MNT}"
	export LIMA_CIDATA_MNT
	exec "${LIMA_CIDATA_MNT}"/boot.sh
	owner: root:root
	path: /var/lib/cloud/scripts/per-boot/00-lima.boot.sh
	permissions: '0755'
	{{- if .DNSAddresses }}
	# This has no effect on systems using systemd-resolved, but is used
	# on e.g. Alpine to set up /etc/resolv.conf on first boot.
	manage_resolv_conf: true
	resolv_conf:
	nameservers:
	{{- range $ns := $.DNSAddresses }}
	- {{$ns}}
	{{- end }}
	{{- end }}
	{{ with .CACerts }}
	ca_certs:
	remove_defaults: {{ .RemoveDefaults }}
	{{- if .Trusted}}
	trusted:
	{{- range $cert := .Trusted }}
	- |
	{{- range $line := $cert.Lines }}
	{{ $line }}
	{{- end }}
	{{- end }}
	{{- end }}
	{{- end }}
	{{- if .BootCmds }}
	bootcmd:
	{{- range $cmd := $.BootCmds }}
	- |
	# We need to embed the params.env as a here-doc because /mnt/lima-cidata is not yet mounted
	while read -r line; do [ -n "$line" ] && export "$line"; done <<'EOF'
	{{- range $key, $val := $.Param }}
	PARAM_{{ $key }}={{ $val }}
	{{- end }}
	EOF
	{{- range $line := $cmd.Lines }}
	{{ $line }}
	{{- end }}
	{{- end }}
	{{- end }}

Is it possible to unify bootcmd into the /var/lib/cloud/scripts/per-boot scripts? (What are those differences?)

[jandubois]

(What are those differences?)

I think the main difference is that bootcmd is running much earlier in the boot sequence (as the cloud-init-local.service). I'm not sure when that is needed though.

[afbjorklund]

I'm not sure when that is needed though.

I think it originally came from this feature request:

• Allow further customization of Lima’s boot workflow #1093

[jandubois]

I think it originally came from this feature request:

Yes, but it was proposed as just something that might be useful, without an actual need for it:

Another nice to have feature is allowing Lima users to customize cloud init’s cloud-init-local.service behavior via bootCmds, which run very early in the boot process (more info here). Users can use this feature to disable unnecessary services via systemctl (or other means, depending on the OS), or run other arbitrary commands for other reasons.

It is totally possible that nobody is using it at all.