Mageia2 on EC2: Cruising Altitude

This is my fourth post on getting Mageia2 running on Amazon Web Services' Elastic Compute Cloud. See my first post in the series for an overview.

In the last post, I addressed the problem of having only a test kernel by tweaking the Mageia kernel SRPM and creating a gzipped kernel that can be used with the version of PV-GRUB supplied by Amazon. Now I'll walk through the steps of building an EBS backend instance instead of an instance-store backed instance.

You need a working Mageia setup on an instance-store backed instance before you can create the EBS backed one. Just launch the AMI created in a previous step and then attach a 32GB EBS volume to it. Using the EC2 API tools, you attach the volume like this:

SIZE=32
TARGETAZ=us-east-1a
INSTID=i-09abcdef

CMD=($(ec2-create-volume --size $SIZE --availability-zone $TARGETAZ --type standard))
VOLID=${CMD[1]}
ec2-attach-volume $VOLID --instance $INSTID --device /dev/sdg


You will also need some other components:

1. "kernel-server" RPM created in a last post.
2. A copy of ec2-get-ssh.sh for the mageia user

The second component is so you don't have to embed passwords in your AMI, but instead uses ssh public keys that are imported to (or generated by) AWS.

Another difference is that we add the kernel to the skip.list for upgrades, as we don't want to get a non-gzipped kernel. So, here's the steps for setting it up:

mkdir $HOME/ec2

# everything forward needs to be done as root 
sudo bash -o vi
cd $HOME/ec2
export PATH=$PATH:/sbin:/usr/sbin

# setup the filesystem
/sbin/mkfs -t ext4 /dev/xvdg

# mount the image for chroot
export CHRDIR=$HOME/ec2/loop
mount /dev/xvdg $CHRDIR

# create the minimum devices
mkdir $CHRDIR/dev
/sbin/makedev $CHRDIR/dev console
/sbin/makedev $CHRDIR/dev null
/sbin/makedev $CHRDIR/dev zero

# setup the minimum filesystems
mkdir $CHRDIR/etc
cat > $CHRDIR/etc/fstab << EOF
/dev/xvda1 /         ext3    defaults        1 1
none       /dev/pts  devpts  gid=5,mode=620  0 0
none       /dev/shm  tmpfs   defaults        0 0
none       /proc     proc    defaults        0 0
none       /sys      sysfs   defaults        0 0
EOF

# add required /proc filesystem
mkdir $CHRDIR/proc
mount -t proc none $CHRDIR/proc

# choose the best/fastest mirror
GET http://mirrors.mageia.org/api/mageia.2.x86_64.list | grep country=US
# setup the urpmi media locations in the chroot
urpmi.addmedia --distrib --urpmi-root $CHRDIR http://mirrors.kernel.org/mageia/distrib/2/x86_64
# install the minimum packages
urpmi --auto --urpmi-root $CHRDIR basesystem urpmi locales-en sshd sudo dhcp-client

# MASSIVE HACK TIME
rpm --root=$CHRDIR -Uhv custom-kernel/kernel-server-3.3.8-2.mga2-1-1.mga2.x86_64.rpm

# cleanup desktop kernel
chroot $CHRDIR
urpme kernel-desktop-3.3.8-2.mga2-1-1.mga2
rm -f initrd-desktop.img  vmlinuz-desktop 
# confirm there's a good initrd
cd /boot
stat initrd-3.3.8-server-2.mga2.img
mkinitrd initrd-3.3.8-server-2.mga2.img 3.3.8-server-2.mga2
exit

# set the kernel to load on boot
cat > $CHRDIR/boot/grub/menu.lst << EOF
default=0
timeout=0
title linux
  root (hd0)
  kernel /boot/vmlinuz-server ro root=/dev/xvda1 console=hvc0 BOOT_IMAGE=linux-nonfb
  initrd /boot/initrd-server.img
EOF

# do not upgrade the kernel, until upstream fixes the xz/gz issue
test -f $CHRDIR/etc/urpmi/skip.list || cp -p $CHRDIR/etc/urpmi/skip.list $CHRDIR/etc/urpmi/skip.list.orig
cat > $CHRDIR/etc/urpmi/skip.list << EOF
# Here you can specify the packages that won't be upgraded automatically
# for example, to exclude all apache packages :
# /^apache/
/^kernel/
EOF

# configure the chroot network for ec2
cat > $CHRDIR/etc/sysconfig/network-scripts/ifcfg-eth0 << EOF
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
TYPE=Ethernet
USERCTL=yes
PEERDNS=yes
IPV6INIT=no
EOF
cat > $CHRDIR/etc/sysconfig/network << EOF
NETWORKING=yes
CRDA_DOMAIN=US
EOF

# configure ssh
test -f $CHRDIR/etc/ssh/sshd_config.orig || cp -p $CHRDIR/etc/ssh/sshd_config $CHRDIR/etc/ssh/sshd_config.orig
cat $CHRDIR/etc/ssh/sshd_config.orig |
    sed -e 's/^#UseDNS yes/UseDNS no/g' |
    sed -e 's/^PermitRootLogin no/PermitRootLogin without-password/g' > $CHRDIR/etc/ssh/sshd_config
# create login account
chroot $CHRDIR /usr/sbin/useradd --create-home --home /home/mageia --shell /bin/bash mageia
(umask 0227; echo "mageia ALL=(ALL) NOPASSWD:ALL" > $CHRDIR/etc/sudoers.d/mageia)

# setup ssh public key
cp ec2-get-ssh $CHRDIR/etc/rc.d/init.d/ec2-get-ssh
chmod 0750 $CHRDIR/etc/rc.d/init.d/ec2-get-ssh
chown root:root $CHRDIR/etc/rc.d/init.d/ec2-get-ssh
chroot $CHRDIR /sbin/chkconfig ec2-get-ssh on

# dismount the chroot
umount $CHRDIR/proc
umount -d $CHRDIR

Now that the EBS volume is all set, it needs to be snapshotted and registered as an AMI. Here's what you do:

ec2-detach-volume $VOLID --instance $INSTIT--device /dev/sdg

# create a snapshot
CMD=($(ec2-create-snapshot --description "Mageia 2" $EBSVOL))
SNAPID=${CMD[1]}

# create AMI
AKIID="aki-88aa75e1"
ec2-register --name "Mageia 2" --description "Mageia 2" \
    --architecture x86_64 --root-device-name /dev/sda1 \
    --block-device-mapping /dev/sda1=$SNAPID --kernel $AKIID

Now you're ready to launch your EBS back Mageia2 Linux instance! Enjoy!