virt-customize

TLDR

Set root password

$ virt-customize -a [image.qcow2] --root-password password:[newpass]

Install packages

$ virt-customize -a [image.qcow2] --install [nginx,vim]

Upload file to image

$ virt-customize -a [image.qcow2] --upload [local.conf]:[/etc/app.conf]

Run shell script

$ virt-customize -a [image.qcow2] --run [setup.sh]

Run command

$ virt-customize -a [image.qcow2] --run-command "[systemctl enable nginx]"

Inject SSH key

$ virt-customize -a [image.qcow2] --ssh-inject [root]:file:[~/.ssh/id_rsa.pub]

Set timezone

$ virt-customize -a [image.qcow2] --timezone [America/New_York]

Set hostname

$ virt-customize -a [image.qcow2] --hostname [myserver]

SYNOPSIS

virt-customize -a image [options]

virt-customize modifies virtual machine disk images by installing packages, editing configuration, uploading files, and running scripts. It is part of the libguestfs tools suite.
The tool works by mounting the disk image using libguestfs and performing operations in a secure, isolated environment. The VM must be shut down before customization.
Customization scripts run inside a small appliance chrooted into the guest filesystem. Limited network access is available for package downloads.
This tool is useful for preparing cloud images, creating golden images, and automating VM provisioning.

PARAMETERS

-a, --add file

Disk image file to customize.

--root-password method:arg

Set root password.

--password user:method:arg

Set user password.

--install packages

Install packages (comma-separated).

--uninstall packages

Remove packages.

--update

Update all packages.

--upload local:remote

Upload file to image.

--copy-in local:remotedir

Copy files/dirs into image.

--run script

Run shell script in image.

--run-command cmd

Run single command.

--ssh-inject user:file:keyfile

Inject SSH public key.

--timezone tz

Set timezone.

--hostname name

Set hostname.

--edit file:expr

Edit file with Perl expression.

--delete path

Delete file or directory.

--commands-from-file file

Read commands from file.

-v, --verbose

Enable verbose output.

CAVEATS

VM must be shut down. Don't run as root unless necessary. Snapshot disk before modifying production images. Some operations require specific guest OS support. SELinux relabeling may be needed.

HISTORY

virt-customize is part of libguestfs, created by Red Hat for virtual machine image manipulation. The toolset provides safe, scriptable access to VM disk images without requiring the guest to be running.