Portal:JeOS:Documentation:libguestfs-tools

JeOS : Customizing openSUSE Leap JeOS images with guestfs-virt-tools

What is guestfs?

guestfs project has a set of tools for manipulating virtual machine images of several formats

You can use a SUSE based machine and 'zypper in guestfs-tools'. The virt-\* series of commands use a minimal image created using supermin and runs it as a qemu "appliance" that will mount the target images and make modifications to the filesystem.

Notes:

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guestfs on openSUSE had a bug (boo#1136878) that makes the network dysfunctional as a workaround you can:

sudo vim /usr/lib64/guestfs/supermin.d/packages

add "sysconfig-netconfig" to the package list

remove the old appliance (location is based in the user id number):

rm -rf /var/tmp/.guestfs-0/appliance.d

Running any command will rebuild the appliance.

To check you can run:

virt-rescue --network --scratch -v

This will bring a shell in the appliance where you can check proper DNS entries are added in /etc/resolv.conf

/etc/machine-id initialization

The commands of the virt-\* family initialize "/etc/machine-id", JeOS removes the machine-id at build time and try to reinitiliaze it during firstboot.

If control over the machine-id is desirable you will have to be sure to reset this file before starting the image, for that you can use:

virt-sysprep -a openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-kvm-and-xen-Snapshot9.124.qcow2 --operations machine-id

How to customize jeos image:

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Resize the virtual disk

JeOS OpenStack image has a virtual disk size of 1GB only, so it can be executed using the "tiny" flavor that by default has a disk size of 1GB.

So if you need more space in the image for offline manipulation you can use the following steps

First you need to create another qcow2 image to receive the expanded copy, this creates a 3Gb empty image:

qemu-img create -f qcow2 openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current\_EXPANDED.qcow2 3G

Now we can expand the third partition that is the root of the filesystem:

virt-resize --expand /dev/sda3 openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current.qcow2 openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current\_EXPANDED.qcow2

Upload and install a single RPM:

virt-customize -v -a openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current.qcow2 --upload ./RPM/cloud-init-18.5-5.8.1.x86\_64.rpm:/root/ --run-command="rpm -Uvh /root/cloud-init\*.rpm"

Install latest cloud-init on an image bsc#1119397:

virt-customize -v -a openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current.qcow2 --run-command "zypper in -l -y cloud-init cloud-init-config-suse"

Update to latest versions of all packages:

virt-customize -v -a openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current.qcow2 --update

Modifying a file in the image, i.e modifying cloud-init conf Example covers how to circumvent bsc#1120349

You can mount the image using 'guestmount':

mkdir mnt\_dir

guestmount -i --rw -a openSUSE-Leap-15.1-JeOS.x86\_64-15.1.0-OpenStack-Cloud-Current.qcow2 mnt\_dir

vim mnt\_dir/etc/cloud/cloud.cfg

add this, taking care of checking what sections are already there:

system_info:
   # This will affect which distro class gets used
   distro: sles
   # Default user name + that default users groups (if added/used)
   default_user:
     name: sles
     lock_passwd: True
     gecos: sles Cloud User
     groups: [cdrom, users]
     sudo: ["ALL=(ALL) NOPASSWD:ALL"]
     shell: /bin/bash

save any modifications then just unmount the image

guestunmount mnt\_dir