Help: failed building Alpine ISO image

Question

I plan to build a custom Alpine ISO image for Raspberry Pi by following instructions in https://wiki.alpinelinux.org/wiki/How_to_make_a_custom_ISO_image. However, when I followed the instructions, I got errors:

$ apk update && apk add alpine-sdk xorriso syslinux
$ abuild-keygen -i -a -n
$ git clone "http://git.alpinelinux.org/cgit/alpine-iso"
$ make PROFILE=alpine-rpi ALPINE_ARCH=armhf iso
==> modloop: Unpacking kernel modules
fetch 'http://dl-cdn.alpinelinux.org/alpine/v3.5/main/x86_64/APKINDEX.tar.gz'
fetch 'http://dl-cdn.alpinelinux.org/alpine/v3.5/community/x86_64/APKINDEX.tar.gz'
ERROR: unsatisfiable constraints:
  linux-rpi (missing):
    required by: world[linux-rpi]
make: *** [Makefile:85: /root/alpine-iso/isotmp.alpine-rpi/stamp.modloop.kernel.rpi] Error 1

Note that I was running the above commands on an Alpine x86 VM. Did I miss some configurations/commands?

--- Edited ---

Using the following patch (it passes ALPINE_ARCH when updating apk index files), I finally passed the above errors.

diff --git a/Makefile b/Makefile
index f88a6a9..0850156 100755
--- a/Makefile
+++ b/Makefile
@@ -87,6 +87,7 @@ $(MODLOOP_KERNELSTAMP):
    --update \
    --no-script \
    --root $(MODLOOP_DIR)/tmp \
+   --arch $(ALPINE_ARCH) \
    $(MODLOOP_PKGS) $(UBOOT_PKGS)
  @mv "$(MODLOOP_DIR)"/tmp/lib/modules/* "$(MODLOOP_DIR)"/lib/modules/
  @if [ -d "$(MODLOOP_DIR)"/tmp/lib/firmware ]; then \
@@ -144,6 +145,7 @@ $(INITFS_DIRSTAMP):
    --update \
    --no-script \
    --root $(INITFS_DIR) \
+   --arch $(ALPINE_ARCH) \
    $(INITFS_PKGS)
  @cp -r $(APK_KEYS) $(INITFS_DIR)/etc/apk/ || true
  @if ! [ -e "$(INITFS_DIR)"/etc/mdev.conf ]; then \
diff --git a/alpine-rpi.conf.mk b/alpine-rpi.conf.mk
index 53349ca..18ca2bf 100644
--- a/alpine-rpi.conf.mk
+++ b/alpine-rpi.conf.mk
@@ -1,4 +1,5 @@
 ALPINE_NAME     := alpine-rpi
+ALPINE_ARCH     := armhf
 KERNEL_FLAVOR   := rpi rpi2
 MODLOOP_EXTRA   :=
 BOOT_OPTS  := dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1

Unfortunately, I hit another error:

$ make PROFILE=alpine-rpi iso
...
==> initramfs: creating /root/alpine-iso/isotmp.alpine-rpi/isofs/boot/initramfs-rpi
/root/alpine-iso/isotmp.alpine-rpi/initfs.rpi/lib/ld-musl-x86_64.so.1: Not found.
libc.musl-x86_64.so.1: Not found.
/usr/bin/lddtree: cd: line 284: can't cd to libc.musl-x86_64.so.1
...
==> initramfs: creating /root/alpine-iso/isotmp.alpine-rpi/isofs/boot/initramfs-rpi2
/root/alpine-iso/isotmp.alpine-rpi/initfs.rpi2/lib/ld-musl-x86_64.so.1: Not found.
libc.musl-x86_64.so.1: Not found.
/usr/bin/lddtree: cd: line 284: can't cd to libc.musl-x86_64.so.1
==> iso: generating repository
mkdir -p "/root/alpine-iso/isotmp.alpine-rpi/isofs/apks/armhf"
sed -e 's/\#.*//' alpine-rpi.packages \
    | xargs apk fetch  --keys-dir /etc/apk/keys --repositories-file /etc/apk/repositories \
        --output /root/alpine-iso/isotmp.alpine-rpi/isofs/apks/armhf \
        --recursive || { rm /root/alpine-iso/isotmp.alpine-rpi/isofs/apks/armhf/*.apk; exit 1; }
raspberrypi: unable to select package (or it's dependencies)
omxplayer: unable to select package (or it's dependencies)
rm: can't remove '/root/alpine-iso/isotmp.alpine-rpi/isofs/apks/armhf/*.apk': No such file or directory
make: *** [Makefile:281: /root/alpine-iso/isotmp.alpine-rpi/isofs/apks/armhf/APKINDEX.tar.gz] Error 1

After investigating Makefile, it seems that ALPINE_ARCH was not passed to mkinitfs. It's not clear to force mkinitfs to use armhf instead of x86_64 since there is no option available to do that.

Answer 1

Your problem lies here in the links where you are using the fetch command:

fetch 'http://dl-cdn.alpinelinux.org/alpine/v3.5/main/x86_64/APKINDEX.tar.gz'
fetch 'http://dl-cdn.alpinelinux.org/alpine/v3.5/community/x86_64/APKINDEX.tar.gz'

These links might be broken or the location could have been changed. Check to see if these are the right links or if there is any mirror sites available. If you can find a mirror link and try it, that will resolve your issue.