How to add ssh key to qcow2 Linux cloud images using virt-sysprep

To add an ssh key to a qcow2 Linux cloud image using virt-sysprep, you will need to have the libguestfs-tools package installed on your system. This package provides the virt-sysprep command and other tools for modifying virtual machine images.

Here's an example of how you can use virt-sysprep to add an ssh key to a qcow2 Linux cloud image:

1. First, create a file containing the ssh key that you want to add to the image. For example, if you want to add an ssh key stored in the file ~/.ssh/id_rsa.pub, you can use the following command:

cat ~/.ssh/id_rsa.pub > ssh-key.txt

This will create a new file named ssh-key.txt containing the contents of the id_rsa.pub file.

2. Use the virt-sysprep command to add the ssh key to the qcow2 image. For example, to add the ssh key stored in ssh-key.txt to the qcow2 image my-image.qcow2, you can use the following command:

virt-sysprep --add ssh-key.txt -a my-image.qcow2

This will add the ssh key stored in ssh-key.txt to the authorized_keys file in the root user's home directory on the qcow2 image.

3. Use the qemu-img command to create a new qcow2 image from the modified image. For example:

qemu-img convert -O qcow2 my-image.qcow2 my-modified-image.qcow2

This will create a new qcow2 image named my-modified-image.qcow2 containing the changes made with virt-sysprep, including the added ssh key.

Note: The virt-sysprep command has many options and features available for modifying virtual machine images. Consult the documentation and online resources for more information on the various options and features available with this command. It is recommended to use virt-sysprep with caution, as improper use can cause problems or disrupt the operation of the virtual machine.