Classic install or sys mode on Raspberry Pi
This page documents the traditional or sys mode installation of Alpine Linux on a Raspberry Pi.
Preparation
Download the Alpine for Raspberry Pi tarball. Use the compatibility list when choosing image/file to download. Sha256 and GPG links appear next to the link to check the download.
Create an MBR partition table with two partitions on an 8 GB (or larger) class 10 sd-card:
- First one, a fat16 type, of 256MB. You may have to set
bootandlbaflags - The second one, an ext4 type, occupying the remaining space on the media
Eject and re-insert your SD card to ensure recognition of all the partitions.
Go into the first partition (fat16).
Untar the archive with tar:
tar zxvf ~/Download/alpine-rpi-3.21.3-armhf.tar.gz
If using the UART is required, add a file named usercfg.txt into the partition containing the following single line:
enable_uart=1
For headless use, you can add the following parameters to maximize available memory (32 megs is required for the rpi bootloader):
gpu_mem=32
to enable audio support:
dtparam=audio=on
Eject the SD card properly. Insert it into the Raspberry Pi. Plug in a usb keyboard as well as the HDMI and network cables. Power on.
When the command prompt displays, log in as root. (no password)
Installation
Alternate Installation Method1
 The below section needs to be integrated into this page |
Split your SD card into two partitions: the FAT32 boot partition described above (in this example it'll be mmcblk0p1) , and a second partition to hold the root filesystem (here it'll be mmcblk0p2). Boot and configure your diskless system as above, then create a root filesystem:
apk add e2fsprogs mkfs.ext4 /dev/mmcblk0p2
Now do a disk install via a mountpoint. The setup-disk script will give some errors about syslinux/extlinux, but you can ignore them.
The Raspberry Pi doesn't need them to boot.
mkdir /stage mount /dev/mmcblk0p2 /stage setup-disk -o /media/mmcblk0p1/MYHOSTNAME.apkovl.tar.gz /stage # (ignore errors about syslinux/extlinux)
Add a line to /stage/etc/fstab to mount the Pi's boot partition again:
/dev/mmcblk0p1 /media/mmcblk0p1 vfat defaults 0 0
Now add a root=/dev/mmcblk0p2 parameter to the Pi's boot command line, either cmdline-rpi2.txt or cmdline-rpi.txt depending on model:
mount -o remount,rw /media/mmcblk0p1 sed -i '$ s/$/ root=\/dev\/mmcblk0p2/' /media/mmcblk0p1/cmdline-rpi2.txt
You might also consider overlaytmpfs=yes here, which will cause the underlying SD card root filesystem to be mounted read-only, with an overlayed tmpfs for modifications which will be discarded at shutdown.
N.B. the contents of /boot will be ignored when the Pi boots. It will use the kernel, initramfs, and modloop images from the FAT32 boot partition. To update the kernel, initfs or modules, you will need to manually (generate and) copy these to the boot partition or you could use bind mount, in which case, copying the files to boot partition manually, is not needed.
echo /media/mmcblk0p1/boot /boot none defaults,bind 0 0 >> /etc/fstab
Execute the following commands. Make sure there is an internet connection available otherwise setting up the apk mirrors will fail.
setup-alpine
Set the keyboard map, the timezone, how to connect to the network (dhcp is the best method), say none at save config and save cache.
apk update
If the extra space in the sd card was left empty, a partition must be created now:
apk add cfdisk e2fsprogs # or the tool of your choice cfdisk /dev/mmcblk0 # create the new partition with the free space mkfs.ext4 /dev/mmcblk0p2 # create the ext4 filesystem in the new partition
Raspberry Pi has no hardware clock, so synchronize with an ntp server:
apk add chrony
service chronyd restart
#12353
mount /dev/mmcblk0p2 /mnt # The second partition, in ext4 format, where Alpine Linux is installing in sys mode export FORCE_BOOTFS=1 # work around for issue 12353 setup-disk -m sys /mnt mount -o remount,rw /media/mmcblk0p1 # An update in the first partition is required for the next reboot.
You may get some warning about syslinux when you run setup-disk. You can safely ignore this.
Update boot partition (keep alpine-rpi* image layout)
From here we can either update boot partition to keep the alpine-rpi* image layout or to keep the system partition/setup-alpine's layout (see next section). We only need one of the two. Not both.
Clean up the boot folder in the first partition to drop unused files:
rm -f /media/mmcblk0p1/boot/* cd /mnt # We are in the second partition rm boot/boot # Drop the unused symbolic link
Move the image and initramfs for Alpine Linux into the right place:
mv boot/* /media/mmcblk0p1/boot/ rm -Rf boot mkdir media/mmcblk0p1 # It's the mount point for the first partition on the next reboot
Don't worry about the error when you execute the following:
ln -s media/mmcblk0p1/boot boot
Update boot partition (keep system partition/setup-alpine layout)
It turns out that the system partition created by setup-alpine has a working boot layout. To keep this, perform the following steps instead of the steps in the previous chapter.
Clean up the boot / first partition to drop unused files:
rm -Rf /media/mmcblk0p1/* cd /mnt # We are in the second partition rm boot/boot # Drop the unused symbolink link
Move the boot folder created by setup-alpine into the right place:
cd /media/mmcblk0p1 mkdir boot
cd /mnt mv boot/* /media/mmcblk0p1/ rm -Rf boot mkdir media/mmcblk0p1 # It's the mount point for the first partition on the next reboot
Don't worry about the error when you execute the following:
ln -s media/mmcblk0p1 boot
End of update boot partition - continue here in both cases
Update /etc/fstab:
echo "/dev/mmcblk0p1 /media/mmcblk0p1 vfat defaults 0 0" >> etc/fstab sed -i '/cdrom/d' etc/fstab # Of course, you don't have any cdrom or floppy on the Raspberry Pi sed -i '/floppy/d' etc/fstab cd /media/mmcblk0p1
If you want to activate the edge repository:
sed -i '/edge/s/^#//' etc/apk/repositories # But enable the repository for community if you want vim, mc, php, apache, nginx, etc.
For the next boot, indicate that the root filesystem is on the second partition. If the cmdline.txt file
contains a line that starts with /root, then use sed:
sed -i 's/$/ root=\/dev\/mmcblk0p2 /' /media/mmcblk0p1/cmdline.txt reboot
That works on Raspberry Pi 3B and 1B, but if you have the 1B version, you'll need to be very, very patient (several tens of minutes).
If a hard disk is connected via usb, you can replace the /dev/mmcblk0p2 above with /dev/sda1, for example.
If you don't want to use sed, you can use the nano editor instead, after executing the following command:
apk add nano
Post-installation
See the Raspberry_Pi#Post_Installation for common post-installation steps.
Additionally, the following may be of value on a sys mode installation:
If you want a cool editor (vim), a file manager (mc), and to determine which tasks are running and which services are starting on boot (htop), install the packages with this command:
apk add vim mc htop
The RPI 3B has wifi on board. To start the service for the encrypted key using wpa2 protocol:
apk add wpa_supplicant
rc-update add wpa_supplicant boot
service wpa_supplicant start
setup-interfaces
Replace the IP address by dhcp for all the interfaces if necessary; select the SSID network for wifi, add the password.
ip addr # to find the IP address for all interfaces
If you want to connect to your RPI via ssh, an additional user (foo) and the sudo package are required because it's forbidden to connect as root:
apk add sudo adduser foo adduser foo wheel visudo
Uncomment line #82 with wheel ALL=(ALL) ALL. If vim is installed, save the changes by typing Esc :x
Troubleshooting
Following the preparation instructions for setting up the boot partition as outlined, using the armv7 image (3.10.3), my rpi2 would not even boot, and I was trapped at the dreaded rainbow screen, with the green led blinking a few times in a row, repeatedly.
The rpi2 I had appears to require fat32 for the boot partition, NOT fat16 as suggested in the instructions. Use linux fdisk to set the boot partition type as "c" (for fat32/lba) and set the lba and boot flags for the partition as suggested. Create the boot partition filesystem as fat32 with:
mkdosfs -F 32 /dev/sdX1
Mount and unpacke the tarball to that, and everything should work as documented after the prep instructions.
After booting, you may find less system memory available than you expect. Currently the Pi requires a minimum of 32 megs of memory for the gpu, to boot unless you have the cut down boot loader installed, in which case you can use 16. However, you may find more gpu memory is still being used, even if you configure it for less, if you enable audio or camera support. To find out how your system is actually split:
apk add raspberrypi-utils-vcgencmd
vcgencmd get_mem gpu
vcgencmd get_mem arm