Digital Ocean: Alpine Linux

This guide instructs you on how to put Alpine Linux on a Digital Ocean (referral link for $10) droplet.

Requirements

• Digital Ocean account
• Local Docker installation (used to generate the Alpine root filesystem)

Process

Generate Alpine root file system

1. Ensure Docker is running locally.
2. Download and unzip gliderlabs/docker-alpine.
   • wget -O docker-alpine-master.zip https://github.com/gliderlabs/docker-alpine/archive/master.zip
   • unzip docker-alpine-master.zip
3. Build the builder.
   • docker build -t docker-alpine-builder docker-alpine-master/builder/
4. Build the root file system (change v3.3 to the Alpine version you want to build).
   • docker run --name alpine-builder docker-alpine-builder -r v3.4
5. Copy the root file system from the container.
   • docker cp alpine-builder:/rootfs.tar.gz .
6. (Optional) Clean up builder.
   • docker rm alpine-builder
   • docker rmi docker-alpine-builder
   • rm -rf docker-alpine-master{,.zip}

You should now have rootfs.tar.gz in your current directory.

Prepare droplet

1. Create droplet.
   • In your Digital Ocean control panel, click "Create Droplet".
   • Select the "Debian 7.11 x64" image, fill in the rest of your information, and click "Create Droplet".
2. Transfer rootfs.tar.gz to the droplet.
   • scp rootfs.tar.gz root@<IP address>:
3. SSH into the droplet.
   • ssh root@<IP address>
4. Inside the droplet, extract the Alpine files onto your hard drive.
   • mkdir /alpine
   • tar xf rootfs.tar.gz -C /alpine
   • poweroff

Setup root file system

1. In your Digital Ocean droplet control panel, click "Kernel".
2. Click "Mount Recovery Kernel".
3. Switch on your droplet.
4. Click "Console".
5. In the recovery console, move the extracted Alpine files into the root of your drive.
   • mkdir /mnt
   • mount -t ext4 /dev/vda1 /mnt
   • mv /mnt/etc/network/interfaces /mnt/alpine/etc/network/
   • mv /mnt/root/.ssh/ /mnt/alpine/root/
   • mv /mnt/etc/fstab /mnt/alpine/etc/
   • mv /mnt/alpine/ /tmp/
   • rm -rf /mnt/*
   • mv /tmp/alpine/* /mnt/
   • umount /mnt/
   • poweroff
6. Close the recovery console.
7. Select a kernel (e.g. search for "3.2.0-4-amd64"), then click "Change".
8. Switch on your droplet.

Configuring Alpine

1. Click "Console" in your droplet control panel.
2. Login as root.
3. Enable writing to the file system.
   • mount -o rw,remount /dev/vda1 /
   • vi /etc/fstab
   • Set the 4th column (options) of the / mount point to defaults
   • Save and exit.
4. Configure networking and SSH.
   • setup-hostname
   • setup-dns
   • service networking restart
   • apk update
   • setup-sshd
5. Enable services.
   • rc-update add hostname boot
   • rc-update add networking boot
   • rc-update add urandom boot
   • rc-update add crond
   • rc-update add swap boot
6. Reboot.
   • reboot
7. Close the console.

After removing the old SSH fingerprint from your local machine's ~/.ssh/known_hosts file, you should now be able to SSH into your droplet.

8. If you need a modules to work:
   • wget http://ftp.de.debian.org/debian/pool/main/l/linux/linux-image-3.16.0-4-amd64_3.16.7-ckt25-2_amd64.deb
   • apk add dpkg
   • apk add tar
   • dpkg-deb -x linux-image-3.16.0-4-amd64_3.16.7-ckt25-2_amd64.deb /tmp/out/
   • mv /tmp/out/lib/modules/ /lib/
   • depmod -a
   • rm linux-image-3.16.0-4-amd64_3.16.7-ckt25-2_amd64.deb
   • rm /tmp/out/ -fr

License

Creative Commons Attribution 4.0 International License

Author

Tim Cooper (tim.cooper@layeh.com)