boot2docker-qemu

gistfile1.txt

This is based on http://serverascode.com/2014/03/13/boot2docker-qemu.html

After running the script, you should be able to login using:

ssh-keygen -R $IP # if the host-key is already know for that IP-address
ssh-keyscan -p 22 $IP > /var/lib/libvirt/images/boot2docker1.hostfile
ssh-keygen -H -f /var/lib/libvirt/images/boot2docker1.hostfile
rm -f /var/lib/libvirt/images/boot2docker1.hostfile.old
ssh -p 22 -o UserKnownHostsFile=/var/lib/libvirt/images/boot2docker1.hostfile -i /var/lib/libvirt/images/boot2docker1.key docker@$IP

#!/bin/bash

vmtype=boot2docker
num_vms=1
backing_image=boot2docker.img

for ((i=1; i<=num_vms; i++)); do

  virsh destroy ${vmtype}$i > /dev/null
  virsh undefine ${vmtype}$i > /dev/null
  rm -f ./${vmtype}0${i}.xml > /dev/null
  rm -f /var/lib/libvirt/images/${vmtype}$i.img > /dev/null
  rm -f /var/lib/libvirt/images/${vmtype}$i-persist.img > /dev/null
  rm -f /var/lib/libvirt/images/boot2docker$i.key
  rm -f /var/lib/libvirt/images/boot2docker$i.key.pub

#
# Setup partitions for image
#

cat <<-SFDISKOUT > /var/tmp/sfdisk.out.${vmtype}${i}
# partition table of boot2docker1-persist.img
unit: sectors

${vmtype}${i}-persist.img1 : start=     2048, size= 10483712, Id=83
${vmtype}${i}-persist.img2 : start=        0, size=        0, Id= 0
${vmtype}${i}-persist.img3 : start=        0, size=        0, Id= 0
${vmtype}${i}-persist.img4 : start=        0, size=        0, Id= 0
SFDISKOUT

  #
  # Create images
  # 

  pushd /var/lib/libvirt/images > /dev/null
    qemu-img create -f qcow2 -b ${backing_image} ${vmtype}${i}.img > /dev/null
    qemu-img create -f raw ${vmtype}${i}-persist.img 5G
    #sfdisk --force ${vmtype}${i}-persist.img < /var/tmp/sfdisk.out.${vmtype}${i}
    #losetup --offset 1048576 /dev/loop0 ${vmtype}${i}-persist.img
    losetup /dev/loop0 ${vmtype}${i}-persist.img
    #mkfs.ext4 -F -L boot2docker-data /dev/loop0
    mkdir b2d-data
    mkdir -p .ssh
    ssh-keygen -f boot2docker$i.key -N ""
    cat boot2docker$i.key.pub > .ssh/authorized_keys
    chown 1000:50 .ssh -R
    touch "boot2docker, please format-me"
    tar --numeric-owner -cf userdata.tar "boot2docker, please format-me" .ssh/
    dd if=userdata.tar of=/dev/loop0
    rm -f .ssh/authorized_keys
    rmdir .ssh
    rm -f "boot2docker, please format-me"
    rm -f userdata.tar
    sync
    rmdir b2d-data
    losetup -d /dev/loop0
  popd > /dev/null

  rm -f /var/tmp/sfdisk.out.${vmtype}${i}

  chown libvirt-qemu:kvm /var/lib/libvirt/images/${vmtype}$i.img
  chown libvirt-qemu:kvm /var/lib/libvirt/images/${vmtype}$i-persist.img

  vm_uuid=`uuid`

  #
  # Build the libvirt xml file
  #

 cat <<-LIBVIRTXML > ${vmtype}${i}.xml
<domain type='kvm'>
    <uuid>${uuid}</uuid>
    <name>${vmtype}${i}</name>
    <memory>4194304</memory>
    <os>
            <type>hvm</type>
            <boot dev="hd" />
    </os>
    <features>
        <acpi/>
    </features>
    <vcpu>1</vcpu>
    <devices>
        <disk type='file' device='disk'>
            <driver type='qcow2' cache='none'/>
            <source file='/var/lib/libvirt/images/${vmtype}${i}.img'/>
            <target dev='vda' bus='virtio'/>
        </disk>
        <disk type='file' device='disk'>
      	    <driver type='raw' cache='none'/>
            <source file='/var/lib/libvirt/images/${vmtype}${i}-persist.img'/>
            <target dev='vdb' bus='virtio'/>
        </disk>

  <interface type='network'>
     <source network='default'/>
            <model type='virtio'/>
            <mac address='fa:16:3e:18:89:0${i}'/>
  </interface>


    </devices>
</domain>
LIBVIRTXML

  #
  # Define and start the vm
  #

  virsh define ${vmtype}${i}.xml > /dev/null
  if virsh start ${vmtype}${i} > /dev/null; then
	echo "${vmtype}${i} started"
  fi
  sleep 1

done

virsh list --all
exit 0

Darn, I thought when I would do it the boot2docker way. It would persist, but the SSH-key in /home/docker is gone after shutdown.

Update: OK, so the reason it doesn't work is, because the partition created by boot2docker isn't mounted the second time the VM starts.

This isn't working for some reason: blkid -o device -l -t LABEL=boot2docker-data

For some reason mkfs fails: https://github.com/boot2docker/boot2docker/blob/master/rootfs/rootfs/etc/rc.d/automount#L32

I tried doing it the same way boot2docker does it normally. And just mount the .iso. So there are not 2 disks.

But it doesn't solve the problem.

When the filesystem isn't created. the label isn't set, the filesystem isn't mounted and a tmpfs is mounted under /mnt/vda1/var/lib/docker/aufs. There is nothing mounted at /mnt/vda1. /mnt/vda1/var/lib/boot2docker/userdata.tar does contain the SSH-key.

/home/docker/log.log does contain:
NEW boot2docker managed disk image (/dev/vda): formatting it for use

hacked up a quick connect script:

#! /bin/bash

VM=1

IP=""
while [ "$IP" == "" ]; do
    IP=`grep -i "fa:16:3e:18:89:0$VM" /var/lib/libvirt/dnsmasq/default.leases | awk '{print $3}'`
    if [ "$IP" == "" ]; then
        sleep 1
    fi
done

echo $IP

rm /var/lib/libvirt/images/boot2docker$VM.hostfile
LINES=0
while [ "$LINES" == "0" ]; do
    ssh-keyscan -p 22 $IP 2> >(grep $IP) > /var/lib/libvirt/images/boot2docker$VM.hostfile
    LINES=`cat /var/lib/libvirt/images/boot2docker$VM.hostfile | wc -l`
    echo $LINES
    if [ "$LINES" == "0" ]; then
        sleep 1
    fi
done

ssh-keygen -H -f /var/lib/libvirt/images/boot2docker$VM.hostfile
rm -f /var/lib/libvirt/images/boot2docker$VM.hostfile.old
ssh -p 22 -o UserKnownHostsFile=/var/lib/libvirt/images/boot2docker$VM.hostfile -i /var/lib/libvirt/images/boot2docker$VM.key docker@$IP