Simplify the alpine image build

This fix an issue with apk 3.0 in alpine 3.22.0, which now requires some privileges to create another db

Author: sprat

Dockerfile

@@ -58,14 +58,12 @@ SHELL ["/bin/ash", "-euxo", "pipefail", "-c"]
 
 # install the alpine-base package (for the user space)
 # TODO: or a subset of the packages?
-RUN \
-mkdir -p /out/etc; \
-cp -R /etc/apk/ /out/etc/apk/; \
-apk add --no-cache --root /out --initdb alpine-base
+RUN apk add --no-cache alpine-base
 
 # install the kernel (without installing the dependencies)
 ARG FLAVOR=lts
-RUN apk fetch --no-cache --quiet --stdout linux-$FLAVOR | tar -xz --directory=/out --exclude=.*
+# RUN apk add --no-cache linux-$FLAVOR linux-firmware-none && apk del mkinitfs
+RUN apk fetch --no-cache --quiet --stdout linux-$FLAVOR | tar -xz --directory=/ --exclude=.*
 
 # setup the system
 # by default, we remove all the TTYs in inittab, so they should be added back with the INITTAB_TTYS argument
@@ -80,23 +78,23 @@ BOOT_SERVICES="modules sysctl hostname bootmisc syslog networking hwclock" \
 DEFAULT_SERVICES="acpid ntpd" \
 SHUTDOWN_SERVICES="mount-ro killprocs savecache"
 
-RUN \
-echo "$HOSTNAME" >/out/etc/hostname; \
-mv /out/etc/hosts /out/etc/hosts.target; \
-printf "127.0.1.1\t%s\n" "$HOSTNAME" >>/out/etc/hosts.target; \
-printf "%b\n" "$CMDLINE" >/out/boot/cmdline; \
-sed -i -E '/tty/d;/^#/d;/^$/d' /out/etc/inittab; \
-printf "%b\n" "$INITTAB_TTYS" >>/out/etc/inittab; \
-printf "%b\n" "$NETWORK_INTERFACES" >/out/etc/network/interfaces; \
-rc_add() { for svc in $2; do ln -s "/etc/init.d/$svc" "/out/etc/runlevels/$1/$svc"; done; }; \
+RUN --mount=type=bind,from=alpine-base,source=/,destination=/base \
+echo "$HOSTNAME" >/etc/hostname; \
+cp /base/etc/hosts /etc/hosts.target; \
+printf "127.0.1.1\t%s\n" "$HOSTNAME" >>/etc/hosts.target; \
+printf "%b\n" "$CMDLINE" >/boot/cmdline; \
+sed -i -E '/tty/d;/^#/d;/^$/d' /etc/inittab; \
+printf "%b\n" "$INITTAB_TTYS" >>/etc/inittab; \
+printf "%b\n" "$NETWORK_INTERFACES" >/etc/network/interfaces; \
+rc_add() { for svc in $2; do rc-update add $svc $1; done; }; \
 rc_add sysinit "$SYSINIT_SERVICES"; \
 rc_add boot "$BOOT_SERVICES"; \
 rc_add default "$DEFAULT_SERVICES"; \
 rc_add shutdown "$SHUTDOWN_SERVICES"
 
 # =========================================================
 FROM scratch AS bootable-alpine
-COPY --from=bootable-alpine-rootfs /out /
+COPY --from=bootable-alpine-rootfs / /
 ENTRYPOINT ["/bin/sh"]
 
 # =========================================================