docker-cirros-builder

docker-cirros-builder is a docker container that ships everything needed to build (and customize) x86-64-cirros images.

You can find the home of cirros here.

The current container uses

• cirros 0.3.3
• buildroot 2015.2
• uClib 0.33.2
• busybox 1.23.1
• gcc 4.8.4

and offers some convenience scripts:

• cirros-build - build cirros firmware
• cirros-build-image - build cirros images
• cirros-config-image - config buildroot environment
• cirros-config-image-busybox - configure busybox used within cirros

NOTE: The first run of 'cirros-build-image' triggers the download of a grub package.

To make the generated images easily available on the host machine you may start the instance with a shared directory attached (see example below).

NOTE: This container must be run in privileged mode since it uses loop-mounts.

example

setup

Create the container on your own:

host> docker build -t cirros_x86_64_builder .
...
< this will take some time (for me ... ~15 min) >
...

Or just take the published one from docker hub:

host> docker pull hecke/cirros_x86_64_builder 

Start the instance:

host> docker run --privileged -i -v /tmp/cirros_img/:/root/build/cirros-0.3.3/output/x86_64/images/ -t hecke/cirros_x86_64_builder

Inside the container:

root@667d9cbe3a20:~/build/cirros-0.3.3# cirros-build-image
...
wrote /root/build/cirros-0.3.3/output/x86_64/images/part.img
wrote /root/build/cirros-0.3.3/output/x86_64/images/disk.img
wrote /root/build/cirros-0.3.3/output/x86_64/images/kernel
wrote /root/build/cirros-0.3.3/output/x86_64/images/initramfs
wrote /root/build/cirros-0.3.3/output/x86_64/images/blank.img
wrote /root/build/cirros-0.3.3/output/x86_64/images/filesys.tar.gz
...

NOTE: The format of 'disk.img' is qcow2.

naked qemu

Just start the instance:

host> sudo qemu-system-x86_64 -curses /tmp/cirros_img/disk.img

libvirt

Create a VM using the cirros image:

host> virt-install \
          --connect qemu:///system \
          --virt-type qemu \
          --arch x86_64 \
          --name cirros \
          --ram 64 \
          --disk path=/tmp/cirros_img/disk.img,format=qcow2 \
          --boot hd \
          --vnc \
          --network network=default,mac=52:54:00:9c:42:23 \
          --os-type linux