Install Alpine on Rackspace

== Create a minimal rackspace server ==
Debian 7
512MB, 20GB
== Copy settings from existing server into apkovl ==
The first step is to create Alpine configuration file with basic configuration of the host. We need the new box to start networking and ssh in the beginning so we can reconnect to it after reboot.
Create basic layout for the overlay:
 mkdir overlay
 cd overlay
 mkdir -p etc/ssh etc/network etc/runlevels/{default,boot,sysinit,shutdown} root/.ssh etc/lbu etc/apk
If you want to keep the existing host identity (e.g. SSH key), you can copy them over:
 cp -a /etc/{passwd,group,shadow,gshadow,hostname,network/interfaces,ssh} etc/
 cp /etc/network/interfaces etc/network
 echo "nameserver 8.8.8.8" > etc/resolv.conf
Copy over your ssh authorized_keys and make sure its included in future:
 cp -a /root/.ssh/authorized_keys root/.ssh
 echo "/root/.ssh" > etc/lbu/include
Edit etc/passwd and change bash to /bin/sh.
 sed -i -e '/^root:/s:/bin/bash:/bin/sh:' etc/passwd
Make sure there is no whitespace at end of lines in interfaces file. Busybox ifup is very picky.
 sed -i -e 's/ *$//' etc/network/interfaces
Create the apk world (/etc/apk/world) with essential packages:
 echo "alpine-base iproute2 openssh bash" > etc/apk/world
(bash is technically not needed, but include it in case you forgot to edit your etc/passwd file correctly)
Double check the IP configuration and ssh keys.
Finally, make the essential services start up automatically and create the overlay file:
 ln -s /etc/init.d/{hwclock,modules,sysctl,hostname,bootmisc,syslog} etc/runlevels/boot/
 ln -s /etc/init.d/{devfs,dmesg,mdev,hwdrivers} etc/runlevels/sysinit/
 ln -s /etc/init.d/{networking,sshd} etc/runlevels/default/
 ln -s /etc/init.d/{mount-ro,killprocs,savecache} etc/runlevels/shutdown/
 tar czf ../host.apkovl.tar.gz *
Verify the overlay with "tar tzf" to see that it contains everything in proper places, and ensure it is in the / directory
 tar tzvf ../host.apkovl.tar.gz
 cp ../host.apkovl.tar.gz /
== Install Alpine cd-rom image to hard disk ==
We need to copy over two sets of information: the boot kernel (kernel, initramdisk and boot configuration) and operating system boot data (overlay, apk packages and kernel modules).
Download an alpine iso and mount it; for example
 wget https://dl-3.alpinelinux.org/alpine/v3.2/releases/x86_64/alpine-xen-3.2.2-x86_64.iso
 # We will grab the sha512 sum from another mirror
 wget https://nl.alpinelinux.org/alpine/v3.2/releases/x86_64/alpine-xen-3.2.2-x86_64.iso.sha512
 sha512sum -c alpine-xen-3.2.2-x86_64.iso.sha512 
 mkdir /cdrom
 mount alpine*.iso /cdrom -o loop
Copy the contents of cd-rom image to root of current installation, then setup grub:
cp -a /cdrom/* /
mkdir /cache
umount /cdrom
cat - >/boot/grub/grub.cfg <<EOF 
set default="0"
set timeout="3"
menuentry "Alpine Linux" {
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='(hd0,msdos1)'
	linux /boot/vmlinuz-grsec root=$(blkid /dev/xvda1 | awk '{ print $2 }' | sed 's/"//g') modules=sd-mod,usb-storage,ext3 quiet
 initrd /boot/initramfs-grsec
}
EOF
Download the base iso and copy the apks
wget https://dl-3.alpinelinux.org/alpine/v3.2/releases/x86_64/alpine-3.2.2-x86_64.iso
# We will grab the sha512 sum from another mirror
wget https://nl.alpinelinux.org/alpine/v3.2/releases/x86_64/alpine-3.2.2-x86_64.iso.sha512
sha512sum -c alpine-3.2.2-x86_64.iso.sha512 
mount alpine-3*.iso /cdrom -o loop
cp -a /cdrom/apks/* /apks
Reboot and check that all came back as expected.
== Cleanup == 
Once your server comes back, you are good to go. However, the old Debian system is still on xvda1; and ipv6 is not enabled. These optional steps will fix that:
Enable ipv6
echo "ipv6" >> /etc/modules
modprobe ipv6
You can either reboot or restart networking (and re-log in).
Clear out old stuff:
mount /media/UUID* -o remount,rw
cd /media/UUID*
rm -rf $( find -type d -maxdepth 1 | grep -v 'apks' | grep -v 'boot' | grep -v 'lost+found' )
# the above command will take a while
rm *.iso
find -type l -exec rm {} \;
rm $( find boot -maxdepth 1 -type f | grep -v grsec)
# Now we blank out the disk - this will take a long time
dd if=/dev/zero of=foo
rm foo
sync
reboot and you should be good to go.
Category:Installation