How to make a custom ISO image
This document explains how to build a custom ISO image using the alpine-iso scripts.
First make sure we have the needed tools
Then create signing keys (-i installs them in /etc/apk/keys which is required for later)
Clone (or update) the alpine-iso git repository.
The alpine-iso scripts is a simple makefile which you need to feed with a <name>.conf.mk file and a <name>.packages.
In the <name>.conf.mk we specify
- name of iso image
- (optional) version string. Will default to todays date.
- (optional) either grsec, vserver or pae. Will default to grsec.
- (optional) Extra kernel module packages for the modloop image. For example: dahdi-linux-vserver
- (optional) Path to addidtional apk repository.
The <name>.packages is just a plaintext list of packages that should be included in the ISO image. You should always add alpine-base in there or the CD might not be able to boot. The dependencies for the packages will automatically be pulled in.
A rescue CD example
As an example, let us make a rescue ISO image with packages needed for rescue operations. We call it alpine-rescue
We create the alpine-rescue.conf.mk as follows:
ALPINE_NAME := alpine-rescue KERNEL_FLAVOR := grsec MODLOOP_EXTRA :=
If you are going to use a custom kernel, don't forget to specify KERNEL_FLAVOR_DEFAULT which will set the default kernel to boot.
And then the alpine-rescue.packages as:
alpine-base bkeymaps openssh e2fsprogs mdadm lvm2 parted debootstrap ntfs-3g
Make sure the apk index is up to date (so apk finds the packages):
We create the ISO image by telling the makefile the profile name. The makefile target is iso.
To generate the sha1 sum we use the sha1 make target.
Beside the plaintext package lists in the git repository, there are more documented package lists contributed by Alpine users. Those lists can be transformed into a plain text description by
apk search --exact -v $(cat alpine.packages).
So far the lists below are available (check here for more.)
Live Disk Setup with APKOVL
Once you have customized your custom ISO, you can now setup the live environment to operate outside of the standard installer as follows:
- Generate an APKOVL file with lbu,
- Alpine ISO requires the OVL Volume to be hosted on a web server. Put the APKOVL file on a webserver and identify the url.
- Uncomment the
APKOVLline in the alpine flavor of your choice and set it to the address of your ovl volume.
- Any packages you add to /etc/apk/world of your lbu will automatically be installed onto the live system image.
- If you don't have a web server you can run busybox's httpd temporarily -
busybox -p 127.0.0.1:80
- In general,
lbuwill only handle files in
/etc, to customize this further, you need to add additional files.
- If you want to make a customized installer, you need to create
.default_boot_serviceswhich will cause
mkinitfsto create the defaults for the live image.
Testing your ISO image
Qemu is useful for a quick test of your created ISO image.