How to make a custom ISO image

One way to completely re-build custom images is to use a script like alpine-make-vm-image.

• If you want to make a customized installer, you need to create .default_boot_services which will cause mkinitfs to create the defaults for the live image.

But there is also an alternative:

ISO image customizations with an APKOVL

The "diskless" Alpine ISO images seem to look for an .apkovl volume in system partitions, and offer to save local backups and package cache to mountpoints below /media/. (Besides supporting a boot parameter that points to a web server.)

So

1. Boot the diskless system from ISO, and if necessary create and format a partition.
2. Edit /etc/fstab and mount the writable partition below /media/.
3. Run alpine-setup and choose to save the state to the mounted partition.
4. Customize the system.
5. Generate an APKOVL file with lbu by executing lbu commit

(If instead you put the APKOVL file on a webserver, you would need to supply a custom url with the APKOVL kernel boot parameter.)

Notes:

• See Alpine_Linux_package_management#Local_Cache about managing included packages.
• See lbu about how to customize it to cover files outside of /etc.
• Any packages you add to /etc/apk/world of your lbu will also automatically be installed in the live system.
• If you don't have a web server you can run busybox's httpd temporarily - busybox httpd -p 127.0.0.1:80

Booting an ISO image with local customizations

• From dedicated boot media, obviously.
• (Example included:) Booting and customizing an ISO image with an .apkovl in a Qemu virtual machine.
• Using e.g. Debian's grub-imageboot package and booting .iso files directly, instead of partitions.