Alpine LiveCD Pattern Notes

This file keeps examples and rationale. The normative rules live in contract.md.

Minimal mkimage Profile

profile_<name>() {
    arch="x86_64"
    hostname="<hostname>"
    apkovl="genapkovl-<name>.sh"
    image_ext="iso"
    output_format="iso"
    kernel_flavors="lts"
    initfs_cmdline="modules=loop,squashfs,sd-mod,usb-storage quiet"
    initfs_features="ata base cdrom ext4 mmc nvme raid scsi squashfs usb virtio"
    grub_mod="all_video disk part_gpt part_msdos linux normal configfile search search_label efi_gop fat iso9660 cat echo ls test true help gzio"
    apks="alpine-base linux-lts linux-firmware-none ..."
}

arch is the easiest field to miss. Without it, mkimage may silently skip the profile.

apkovl Placement

genapkovl-<name>.sh must be in the current working directory when mkimage runs.

Example:

cp "genapkovl-<name>.sh" ~/.mkimage/
cp "genapkovl-<name>.sh" /var/tmp/
cd /var/tmp
sh mkimage.sh --workdir /var/tmp/work ...

`/var/tmp` Build Root

Use /var/tmp instead of /tmp:

export TMPDIR=/var/tmp
cd /var/tmp
sh mkimage.sh ...

On Alpine builders, /tmp is often a small tmpfs and firmware/modloop builds overflow it.

Cache Reuse

Typical cache-preserving cleanup:

if [ -d /var/tmp/bee-iso-work ]; then
    find /var/tmp/bee-iso-work -maxdepth 1 -mindepth 1 \
        -not -name 'apks_*' \
        -not -name 'kernel_*' \
        -not -name 'syslinux_*' \
        -not -name 'grub_*' \
        -exec rm -rf {} +
fi

The apkovl section should still be rebuilt every time.

Faster Squashfs

mkdir -p /etc/mkinitfs
grep -q 'MKSQUASHFS_OPTS' /etc/mkinitfs/mkinitfs.conf 2>/dev/null || \
    echo 'MKSQUASHFS_OPTS="-comp lz4 -Xhc"' >> /etc/mkinitfs/mkinitfs.conf

Long-Running Builds

apk add screen
screen -dmS build sh -c "sh build.sh > /var/log/build.log 2>&1"
tail -f /var/log/build.log

Firmware Reminder

Typical extra firmware packages:

linux-firmware-intel
linux-firmware-mellanox
linux-firmware-bnx2x
linux-firmware-rtl_nic
linux-firmware-other

README.md