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NAME

qq2clone - Create and manage QEMU/KVM VMs using template machines and qcow2 images with backing files

SYNOPSIS

qq2clone [OPTION]… COMMAND [ARG]…

DESCRIPTION

qq2clone is a tool for creating and managing clones of QEMU/KVM virtual machines. By using the copy on write feature of qcow2, clones of an existing virtual machine can be made using few system resources and little time or effort.

qq2clone supports creating numerous clones of a template and performing batch operations on them - including the execution of arbitrary commands with qq2clone exec. This simplifies workflows involving large numbers of virtual machines, or the frequent creation/deletion of virtual machines.

To easily establish graphical connections to your virtual machines, qq2clone can use virt-viewer or spicy.

OPTIONS

Not every option has an effect in the context of every command. Specifying an option that has no effect in the context of the command being invoked will not produce an error, it simply will not do anything.

Options are parsed left to right, and right-hand options override left-hand options.

-c, --connection [URI]
Specify a non-default connection URI: sets the value of LIBVIRT_DEFAULT_URI

-C, --copy-disks
When importing or copying a template, make a (full) copy of its image(s)

-f, --no-spice
Do not attempt to connect to a virtual machine’s Spice graphics. Overrides USE_SPICE setting in configuration

-g, --use-spice
Attempt to connect to a virtual machine’s spice graphics. Overrides SPICE setting in configuration

-h, --help
Print basic help information and exit

-n, --no-run
After making a clone of a template, do not run it. Overrides NORUN setting in configuration

-q, --quiet
Suppress most non-error output. Overrides QUIET setting in configuration. Also suppresses various prompts for user choices, either exiting with an error or making a safe default choice depending on the command. Recommended only once familiar with the behavior of qq2clone

-Q, --quieter
This option is (currently) required to appear as the first argument to qq2clone. Suppresses all output, error message or otherwise, except when running interactive commands or commands that require output to be useful. Other commands will receive only an exit code as output. This option is intended for calling qq2clone from a script.

-r, --run
Start a clone after creating it. Overrides NORUN setting in configuration

-s, --storage [LOCATION]
When creating a clone, place new disk image file(s) at location specified by [LOCATION]. [LOCATION] may be one of an absolute filepath, or the name of a libvirt directory type storage pool. Also defines where state files will be saved when using save command. Overrides STORAGE option in configuration

-S, --spicy
Use spicy rather than virt-viewer when connecting to the spice graphics of a clone. Overrides SPICY setting in configuration

-t, --template [NAME]
Use template of given name as context when executing a clone command (see TYPES OF COMMAND section below). Overrides TEMPLATE option in configuration

-v, --verbose
Enable all output. Overrides QUIET setting in configuration

-V, --virt-viewer
Use virt-viewer rather than spicy when connecting to the spice graphics of a clone. Overrides SPICY setting in configuration

TYPES OF COMMAND

There are two main classes of commands: commands that operate directly on templates, and commands that create or operate on clones of templates. To prevent unintended actions, these two command types use slightly different syntax. Commands that operate on templates use the syntax:

qq2clone command [template-name] [ARG] …

while commands that operate on clones use the syntax:

qq2clone --template [template-name] command [ARG] …

Commands operating on clones work within the context of a template defined by --template/-t. Conversely, commands operating on templates specify the template as an argument to the command.

A default template can be defined by the TEMPLATE configuration option, allowing the --template flag to be omitted for commands that operate on clones. Commands operating on templates do not respect this default - the template must always be explicitly defined, reducing the likelihood of accidentally modifying or deleting a template.

TEMPLATE COMMMANDS

copy-template [CURRENT-NAME] [NEW-NAME]
Copy the XML of template CURRENT-NAME to a new template with NEW-NAME. The new template will not receive a copy of the old template’s storage devices - it will point to the same locations

delete-template [NAME]
Delete the template NAME. This operation will succeed only if there are currently no clones of the template

import-template [LIBVIRT-DOMAIN] [NAME], import-template [XML-LOCATION] [NAME] : Import a new template from either an existing libvirt domain, or a fully qualified filepath to a libvirt domain XML file on disk. If argument NAME is ommited, qq2clone will assume you want to use the machine’s name as described in the XML file as the template name

list-templates
List the names of all existing templates

modify-template [NAME] sub-command [ARG] …
Templates can be modified in various ways by invoking modify-template. Each subcommand is described below

modify-template [NAME] commit-image
After an image has been created and modified as desired using modify-template [NAME] prepare-image, commit-image is used to alter a template’s underlying storage device by commiting any changes made using prepare-image. See the commit command described in man qemu-img for more information on how this works

modify-template [NAME] destroy-image
Invoke virsh destroy on a running image created/run through modify-template [NAME] prepare-image. This is generally not wise, as it is equivalent to unplugging a physical machine and could cause corruption to the image that will later be commited as a permanent change to the template’s image

modify-template [NAME] discard-image
Delete an image produced by modify-template [NAME] prepare-image without commiting any changes

modify-template [NAME] edit
Edit the XML document defining a template

modify-template [NAME] rename [NEW-NAME]
Change the name of a template, and all of its clones

modify-template [NAME] prepare-image
Create and/or run a clone that acts as a staging area for changes to the template's actual image. For instance, you could update the template's software by running modify-template [NAME] prepare-image, updating the clone produced by this command, shutting it down, and then running modify-template [NAME] commit-image. This serves a twofold purpose - to prevent incidental damage to an underlying image by providing a safe buffer to work in, and to allow modifications to be safely prepared for an underlying image even while that image has existing clones.

CLONE COMMANDS

A description of the argument SET is described in the SETS section below

clone [NUMBER]
Invoke without any argument to produce a single clone. Supply a number as an argument to specify the number of clones to create

connect [SET]
Start any machine in SET that isn't already running. If any machine in SET has spice graphics and spicy or virt-viewer is installed, use one or the other (chosen by command-line option or configuration) to connect to the graphical console

destroy [SET]
Invoke virsh destroy on any running machine in SET (in other words, if the domain is running forcibly turn it off)

edit [NUMBER]
Edit the XML file of the clone with given number

exec [SET] [command-string]
For every machine in SET, sequentially, execute the contents of the command string in an environment where the following variables are defined per clone: "$uuid", "$name", "$disks" (a newline delimited string containing the machine’s qcow2 disk device filepaths). This is done using bash’s eval command, so contain the command string in single quotes to avoid unexpected behavior. If any instance of exec has a non-zero return value, execution stops.

list [ARG]
Without arguments, list all clones of the current template and their state. With argument “all”, provide list including all clones of every template. With argument “xml”, produce an XML document with information about every template, their clones, and their state. The XML option is not complete - its format is at this point defined only implicitly, by the output of this command.

resume [SET]
Resume any suspended machines in SET

rm [SET]
Destroy every domain in SET (if running), undefine them and delete their storage volumes

rm-wipe [SET]
Destroy every domain in SET (if running), undefine them and wipe their storage volumes using virsh

rm-shred [SET]
Destroy every domain in SET (if running), undefine them and shred their storage volumes

save [SET]
Save execution state of every running domain in SET to file

save-rm [SET]
Delete the state file associated with every machine in SET

start [SET]
Start every machine in SET that is currently not running. For saved domains, their state will be restored

suspend [SET]
Suspend execution of every machine in SET

OTHER COMMANDS

check [TEMPLATE-NAME]
If a clone is deleted, has its UUID changed or is otherwise unavailable, it will remain in qq2clone’s database. Its ID number will remain reserved, and its image files may not be deleted and take up space doing nothing. The check command finds and fixes occurences of this problem. The TEMPLATE-NAME argument is optional, and restricts the check to that template and its clones. Otherwise, all templates are checked

config list, config info [OPTION], config edit [OPTION]
List all configuration options and their current value, get info about a particular option, or edit one

copyright
Output copyright information

license
Output the GNU GPL v2 complete text

setup
Perform initial setup. This is run automatically by the installer script, but can be invoked manually to reset the database to its initial fresh state

SETS

SET is listed as an argument to many commands. SET simply describes a set of virtual machines - clones of a given template. SET is a comma delimited list with no whitespace. SET can be an individual machine or several individual machines designated by number:

1                 (Machine 1)
3,7               (Machines 3 and 7)

Machine numbers can be shown with qq2clone list. Ranges and omitted values are supported as well:

1,2-5,^3          (Machines 1 and 2-5 excluding 3)
1-10,^3-7         (Machines 1-10 excluding 3-7)

Lastly, groups of machines can be addressed by their state:

all               (All machines)
all,^running      (All machines that aren't running)
^running,1-10     (Machines 1-10 except those that are running)

The possible states of a virtual machine are based on the states listed in man virsh, with some modifications. States in qq2clone are:

all
crashed
idle
in-shutdown
off
paused
pmsuspended
running
saved

Specifying machines that do not exist will not cause an error: i.e., 1-10 is a valid set even if only machines 3-7 exist. A set will only cause an error if it is malformed, includes zero existing machines, contains no machines that the command being invoked may act upon, or includes numbers less than 1.

CONFIG

There is no need to refer to the manual to understand configuration options. Use “qq2clone config list” to see all options and their current values, and “qq2clone config info [OPTION]” to get information about a particular option. However, here is the same information provided by qq2clone info for each option

TEMPLATE

This template will be used for commands like clone, rm, destroy when option --template/-t is not specified

Default value: '0'

TEMPLATE_DIR

This is the where template XML files will be kept

Default value: '${HOME}/storage-qq2clone/templates'

QUIET

If set to 1, most non-error output will be suppressed

Default value: '0'

USE_SPICE

If set to 1, attempt to connect to the spice graphics of a virtual machine by default when cloning it, if it is configured to use spice graphics. qq2clone can do this using the programs spicy and virt-viewer. If either is installed on your system during the first run, the default value is '1' (enabled). Otherwise, the default value is '0'

S_TIMEOUT

Wait this many seconds before timing out when trying to connect to a virtual machine's spice graphics.

Default value: '10'

STORAGE

The default location to store clone images when creating them. Changing this location is fine, but it is a good idea to ensure that whatever location you do choose is only used by qq2clone

Default value: '${HOME}/storage-qq2clone/qq2clone-pool'

EXAMPLES

qq2clone import-template Debian
Import a domain on the current libvirt connection of name Debian. Now Debian can be used as a template to produce clone machines

qq2clone import-template /home/user/Debian.xml
Import domain from a libvirt domain XML file to be used as a template

qq2clone --template Debian --run --virt-viewer clone
Make a clone of Debian, run it, and connect to its spice graphics using virt-viewer. All of these options could have instead been defined in the configuration, so that the entire command would be: qq2clone clone

qq2clone --template Debian exec 3 ‘virsh console “$uuid”’
Use virsh to connect to the serial console of template Debian’s clone with number 3 (as shown in qq2clone list)

qq2clone modify-template Debian prepare-image
Create a clone of Debian that can be used as a staging area for permanent changes to the backing template storage device

qq2clone modify-template Debian commit-image
Commit changes to the image Debian staged with the previous command

qq2clone copy-template Debian Debian_2
Copy the XML of template Debian, creating a new template with the same backing storage device that you can edit as you please

LIMITATIONS

Understand what copy on write is. If you modify an image, you will corrupt images using it as a backing file. If you don’t understand what that means, use a search engine to research copy on write. To safely modify a template’s underlying image, use the prepare-image and commit-image subcommands of qq2clone modify-template.

qq2clone uses a virtual machine’s UUID as defined in its libvirt XML file to track it. Don’t change a clone’s UUID.

qq2clone does not support pool types other than directories. If there is another pool type you wish it could use, email me at jgardner7289@protonmail.com and let me know.

FILES

~/.config/qq2clone
This document simply contains a string defining the location at which qq2clone will store files, including the database containing the rest of it configuration options. Currently, qq2clone cannot run without ${HOME} being defined unless a few lines are altered to refer to a new location

~/storage-qq2clone
Directory where qq2clone stores all files and binary executables. Can be changed by modifying ~/.config/qq2clone. This directory is not named “qq2clone” because (at least on Ubuntu 20.04) default Bash completion scripts will see a file starting with “qq2clone” as well as a command in PATH of that name, and fail to insert a space after “qq2clone” when in the home directory

~/storage-qq2clone/qq2clone.db
sqlite3 database containing the configuration information for qq2clone, as well as data about templates and clones

~/storage-qq2clone/qq2clone-pool
Storage pool used for clone images, if the --storage option is not used when creating or saving a clone and the option STORAGE is not changed in the configuration file

~/qq2clone/templates
Directory in which template XML files are stored. These can be edited manually, but it is more advisable to use qq2clone modify-template [template-name] edit

BUGS

If you find a bug, please check to see if it already appears in https://git.j-g-web.com/jesse/qq2clone/issues. If not, email me at jgardner7289@protonmail.com.

COPYRIGHT 2021, Jesse Gardner

This file is part of qq2clone.

qq2clone is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version.

qq2clone is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with qq2clone. If not, see https://www.gnu.org/licenses/.

EXIT VALUES

10
No permission to access file or file doesn’t exist

11
Required software dependencies are not met (see description for a list), or are cannot be found in PATH

12
Invalid command line argument specified, or command specifies an invalid action

13
Problem with a template - i.e., specified template does not exist, or import-template failed because template of specified name already exists

14
Invocation of an external command failed

15
Problem with a libvirt XML file

16
Attempted action with a libvirt tool resulted in failure

17
Could not establish graphical spice connection to machine before timeout expired

18
A file is of the wrong type or does not exist

19
Unexpected error - a bug in qq2clone, or a highly unexpected failure of some command