Build Alpine image via Docker

[owenthereal]

I wonder whether anyone knows how to build an Alpine image via Docker similar to tools/docker/debian. I'm stuck at mounting the 9p filesystem

[SuperMaxusa]

Here is my proof-of-work Alpine Linux on 9pfs, feel free for suggestions.

1. Create Dockerfile

FROM i386/alpine:3.18.6

ENV KERNEL=lts
ENV HOSTNAME=localhost
ENV ROOT_PASSWORD=root

# Installing base packages, you can add additional packages here (community repo is enabled)
RUN apk add openrc alpine-base agetty alpine-conf

# Install newer mkinitfs from edge (todo: remove this when 3.19+ has worked properly with 9pfs)
RUN apk add mkinitfs --no-cache --allow-untrusted --repository https://dl-cdn.alpinelinux.org/alpine/edge/main/ 

# Installing kernel and remove unused drivers for linux-lts
RUN if [ "$KERNEL" == "lts" ]; then \
    apk add linux-lts linux-firmware-none; \
else \
    apk add linux-$KERNEL; \
fi

# Setting root password and hostname
RUN echo "root:$ROOT_PASSWORD" | chpasswd
RUN setup-hostname $HOSTNAME

# Enable autologin into root on tty1, also you can use autologin.c instead agetty
# (see https://wiki.alpinelinux.org/wiki/TTY_Autologin#By_compiling_your_own_autologin_wrapper)
RUN sed -i 's/getty 38400 tty1/agetty --autologin root tty1 linux/' /etc/inittab

# Adding networking.sh script (works only on lts kernel yet)
# (https://github.com/copy/v86/blob/master/tools/docker/debian/networking.sh)
RUN if [ "$KERNEL" == "lts" ]; then \ 
    echo -e "rmmod ne2k-pci && modprobe ne2k-pci\nhwclock -s\nsetup-interfaces -a -r" > /root/networking.sh && \ 
    chmod +x /root/networking.sh; \ 
fi

# Enable minimal needed OpenRC services
# (see https://wiki.alpinelinux.org/wiki/Alpine_Linux_in_a_chroot#Preparing_init_services)
RUN for i in devfs dmesg mdev hwdrivers; do rc-update add $i sysinit; done
RUN for i in hwclock modules sysctl hostname syslog bootmisc; do rc-update add $i boot; done
RUN rc-update add killprocs shutdown

# Generate initramfs with 9p modules
RUN mkinitfs -F "ata base ide scsi virtio ext4 9p" $(cat /usr/share/kernel/$KERNEL/kernel.release)

2. Create image container following by tools/docker/debian/build-container.sh

v86/tools/docker/debian/build-container.sh

Lines 11 to 16 in 360d569

	mkdir -p "$IMAGES"
	docker build . --platform linux/386 --rm --tag "$IMAGE_NAME"
	docker rm "$CONTAINER_NAME" || true
	docker create --platform linux/386 -t -i --name "$CONTAINER_NAME" "$IMAGE_NAME" bash
	docker export "$CONTAINER_NAME" > "$OUT_ROOTFS_TAR"

"$(dirname "$0")"/../../../tools/fs2json.py --exclude /.dockerenv --out "$OUT_FSJSON" "$OUT_ROOTFS_TAR"
# make sure that .dockerenv not included in fs.json (if this happened, remove it from "fsroot" in json)

v86/tools/docker/debian/build-container.sh

Lines 20 to 22 in 360d569

	# Note: Not deleting old files here
	mkdir -p "$OUT_ROOTFS_FLAT"
	"$(dirname "$0")"/../../../tools/copy-to-sha256.py "$OUT_ROOTFS_TAR" "$OUT_ROOTFS_FLAT"

3. Extract kernel and initrd

tar -zxf "$OUT_ROOTFS_TAR" --strip-components=1 boot/*-<lts or virt>

4. Add to V86 starter on your page (or use examples/arch.html):

  var emulator = new V86({
        ...
        bzimage: {
            url: "vmlinuz-...",
        },
        initrd: {
            url: "initramfs-...",
        },
        filesystem: {
            baseurl: "path/to/OUT_ROOTFS_FLAT/",
            basefs: "path/to/OUT_FSJSON",
        },
        bzimage_initrd_from_filesystem: false,
        cmdline: [
            "rw",
            "root=host9p rootfstype=9p rootflags=trans=virtio,cache=loose",
            "nowatchdog"
        ].join(" "),
    });

---

Notes:

• Alpine Linux v3.19.x is not working, it has some problems with writing files into 9p root, that ruined start some services in OpenRC
• Firefox has a long startup problem, probably by Kernel hang with CONFIG_DEBUG_NMI_SELFTEST (Alpine Linux) #797
• For network, set networking_proxy url and run /root/networking.sh

[owenthereal]

@SuperMaxusa:

Can I clarify the values for these two fields? I couldn't find any references:

 bzimage: {
            url: "vmlinuz-...",
        },
        initrd: {
            url: "initramfs-...",
        },

And I followed your guide, but I couldn't get it to work. Would it be possible to provide the build-state.js script and add the alpine.html like the Debian one? I appreciate any help you can provide.

[SuperMaxusa]

Can I clarify the values for these two fields? I couldn't find any references

On step 3 in first version need to extract from rootfs tar files from /boot/, and you have vmlinuz-<virt or lts from $KERNEL> (bzimage field) and initramfs-<virt or lts> (initrd field), next step - insert URL paths to these files in fiels, as step 4.

v86/src/browser/starter.js

Lines 31 to 34 in 2bcfa9d

	* - `bzimage Object` - A Linux kernel image to boot (only bzimage format), see below.
	* - `initrd Object` - A Linux ramdisk image, see below.
	* - `bzimage_initrd_from_filesystem boolean` - Automatically fetch bzimage and
	* initrd from the specified `filesystem`.

However v86 can automatically use kernel and initrd from 9p filesystem, so you can just leave bzimage_initrd_from_filesystem: true, as that mentioned in alpine.md.

v86/tools/docker/alpine/Readme.md

Lines 8 to 13 in 2bcfa9d

	filesystem: {
	baseurl: "../images/alpine-rootfs-flat",
	basefs: "../images/alpine-fs.json"
	},
	bzimage_initrd_from_filesystem: true,

And I followed your guide, but I couldn't get it to work.

Can you tell more about this please, it's about building a filesystem or running into browser/nodejs? I'm have tested now on new cloned repo and it's worked for me without any problems (make sure that your tar from coreutils, Busybox's tar can't delete files into archive):

$ git clone https://github.com/copy/v86.git
$ cd v86/tools/docker/alpine
$ chmod +x build-container.sh
$ ./build-container.sh

Would it be possible to provide the build-state.js script and add the alpine.html like the Debian one?

I'm forget to add autologin on ttyS0, so build-state.js will not works. Here is branch in my fork that has this: https://github.com/SuperMaxusa/v86/tree/alpine-docs

[farhan-ct]

@SuperMaxusa is the 'Invalid argument' issue still there for you when the image is created with 9p?

[SuperMaxusa]

Yes, in Alpine Linux only branch v3.18 has kernel version 6.1.86-r0 at this moment: https://pkgs.alpinelinux.org/package/v3.18/main/x86/linux-lts