1virt-builder(1) Virtualization Support virt-builder(1)
2
6 virt-builder - Build virtual machine images quickly
7
9 virt-builder os-version
10 [-o|--output DISKIMAGE] [--size SIZE] [--format raw|qcow2]
11 [--arch ARCHITECTURE] [--attach ISOFILE]
12 [--append-line FILE:LINE] [--chmod PERMISSIONS:FILE]
13 [--commands-from-file FILENAME] [--copy SOURCE:DEST]
14 [--copy-in LOCALPATH:REMOTEDIR] [--delete PATH] [--edit FILE:EXPR]
15 [--firstboot SCRIPT] [--firstboot-command 'CMD+ARGS']
16 [--firstboot-install PKG,PKG..] [--hostname HOSTNAME]
17 [--install PKG,PKG..] [--link TARGET:LINK[:LINK..]] [--mkdir DIR]
18 [--move SOURCE:DEST] [--password USER:SELECTOR]
19 [--root-password SELECTOR] [--run SCRIPT]
20 [--run-command 'CMD+ARGS'] [--scrub FILE] [--sm-attach SELECTOR]
21 [--sm-register] [--sm-remove] [--sm-unregister]
22 [--ssh-inject USER[:SELECTOR]] [--truncate FILE]
23 [--truncate-recursive PATH] [--timezone TIMEZONE] [--touch FILE]
24 [--uninstall PKG,PKG..] [--update] [--upload FILE:DEST]
25 [--write FILE:CONTENT] [--no-logfile]
26 [--password-crypto md5|sha256|sha512] [--selinux-relabel]
27 [--sm-credentials SELECTOR]
28 virt-builder -l|--list [--long] [--list-format short|long|json] [os-version]
31 virt-builder --notes os-version
33 virt-builder --print-cache
35 virt-builder --cache-all-templates
37 virt-builder --delete-cache
39 virt-builder --get-kernel DISKIMAGE
41 [--format raw|qcow2] [--output OUTPUTDIR]
42
44 Virt-builder is a tool for quickly building new virtual machines. You
45 can build a variety of VMs for local or cloud use, usually within a few
46 minutes or less. Virt-builder also has many ways to customize these
47 VMs. Everything is run from the command line and nothing requires root
48 privileges, so automation and scripting is simple.
49 Note that virt-builder does not install guests from scratch. It takes
51 cleanly prepared, digitally signed OS templates and customizes them.
52 This approach is used because it is much faster, but if you need to do
53 fresh installs you may want to look at virt-install(1) and
54 oz-install(1).
55 The easiest way to get started is by looking at the examples in the
57 next section.
58
60 List the virtual machines available
61 virt-builder --list
62 will list out the operating systems available to install. A selection
64 of freely redistributable OSes is available as standard. You can add
65 your own too (see below).
66 After choosing a guest from the list, you may want to see if there are
68 any installation notes:
69 virt-builder --notes fedora-27
71 Build a virtual machine
73 virt-builder fedora-27
74 will build a Fedora 25 image for the same architecture as virt-builder
76 (so running it from an i686 installation will try to build an i686
77 image, if available). This will have all default configuration
78 (minimal size, no user accounts, random root password, only the bare
79 minimum installed software, etc.).
80 You do not need to run this command as root.
82 The first time this runs it has to download the template over the
84 network, but this gets cached (see "CACHING").
85 The name of the output file is derived from the template name, so above
87 it will be fedora-27.img. You can change the output filename using the
88 -o option:
89 virt-builder fedora-27 -o mydisk.img
91 You can also use the -o option to write to existing devices or logical
93 volumes.
94 virt-builder fedora-27 --format qcow2
96 As above, but write the output in qcow2 format to fedora-27.qcow2.
98 virt-builder fedora-27 --size 20G
100 As above, but the output size will be 20 GB. The guest OS is resized
102 as it is copied to the output (automatically, using virt-resize(1)).
103 virt-builder fedora-27 --arch i686
105 As above, but using an i686 template, if available.
107 Setting the root password
109 virt-builder fedora-27 --root-password file:/tmp/rootpw
110 Create a Fedora 25 image. The root password is taken from the file
112 /tmp/rootpw.
113 Note if you don’t set --root-password then the guest is given a random
115 root password which is printed on stdout.
116 You can also create user accounts. See "USERS AND PASSWORDS" below.
118 Set the hostname
120 virt-builder fedora-27 --hostname virt.example.com
121 Set the hostname to "virt.example.com".
123 Installing software
125 To install packages from the ordinary (guest) software repository (eg.
126 dnf or apt):
127 virt-builder fedora-27 --install "inkscape,@Xfce Desktop"
129 (In Fedora, "@" is used to install groups of packages. On Debian you
131 would install a meta-package instead.)
132 To update the installed packages to the latest version:
134 virt-builder debian-7 --update
136 For guests which use SELinux, like Fedora and Red Hat Enterprise Linux,
138 you may need to do SELinux relabelling after installing or updating
139 packages (see "SELINUX" below):
140 virt-builder fedora-27 --update --selinux-relabel
142 Customizing the installation
144 There are many options that let you customize the installation. These
145 include: --run/--run-command, which run a shell script or command while
146 the disk image is being generated and lets you add or edit files that
147 go into the disk image. --firstboot/--firstboot-command, which let you
148 add scripts/commands that are run the first time the guest boots.
149 --edit to edit files. --upload to upload files.
150 For example:
152 cat <<'EOF' > /tmp/dnf-update.sh
154 dnf -y --best update
155 EOF
156 virt-builder fedora-27 --firstboot /tmp/dnf-update.sh
158 or simply:
160 virt-builder fedora-27 --firstboot-command 'dnf -y --best update'
162 which makes the dnf(8) "update" command run once the first time the
164 guest boots.
165 Or:
167 virt-builder fedora-27 \
169 --edit '/etc/dnf/dnf.conf:
170 s/gpgcheck=1/gpgcheck=0/'
171 which edits /etc/dnf/dnf.conf inside the disk image (during disk image
173 creation, long before boot).
174 You can combine these options, and have multiple options of all types.
176
178 --help
179 Display help.
180 --arch ARCHITECTURE
182 Use the specified architecture for the output image. This means
183 there must be sources providing the requested template for the
184 requested architecture.
185 See also "ARCHITECTURE".
187 --attach ISOFILE
189 During the customization phase, the given disk is attached to the
190 libguestfs appliance. This is used to provide extra software
191 repositories or other data for customization.
192 You probably want to ensure the volume(s) or filesystems in the
194 attached disks are labelled (or use an ISO volume name) so that you
195 can mount them by label in your run-scripts:
196 mkdir /tmp/mount
198 mount LABEL=EXTRA /tmp/mount
199 You can have multiple --attach options, and the format can be any
201 disk format (not just an ISO).
202 See also: --run, "Installing packages at build time from a side
204 repository", genisoimage(1), virt-make-fs(1).
205 --attach-format FORMAT
207 Specify the disk format for the next --attach option. The "FORMAT"
208 is usually "raw" or "qcow2". Use "raw" for ISOs.
209 --cache DIR
211 --no-cache
212 --cache DIR sets the directory to use/check for cached template
213 files. If not set, defaults to either
214 $XDG_CACHE_HOME/virt-builder/ or $HOME/.cache/virt-builder/.
215 --no-cache disables template caching.
217 --cache-all-templates
219 Download all templates to the cache and then exit. See "CACHING".
220 Note this doesn't cache everything. More templates might be
222 uploaded. Also this doesn't cache packages (the --install,
223 --update options).
224 --check-signature
226 --no-check-signature
227 Check/don’t check the digital signature of the OS template. The
228 default is to check the signature and exit if it is not correct.
229 Using --no-check-signature bypasses this check.
230 See also --fingerprint.
232 --colors
234 --colours
235 Use ANSI colour sequences to colourize messages. This is the
236 default when the output is a tty. If the output of the program is
237 redirected to a file, ANSI colour sequences are disabled unless you
238 use this option.
239 --curl CURL
241 Specify an alternate curl(1) binary. You can also use this to add
242 curl parameters, for example to disable https certificate checks:
243 virt-builder --curl "curl --insecure" [...]
245 --delete-cache
247 Delete the template cache. See "CACHING".
248 --no-delete-on-failure
250 Don’t delete the output file on failure to build. You can use this
251 to debug failures to run scripts. See "DEBUGGING BUILDS" for ways
252 to debug images.
253 The default is to delete the output file if virt-builder fails (or,
255 for example, some script that it runs fails).
256 --fingerprint 'AAAA BBBB ...'
258 Check that the index and templates are signed by the key with the
259 given fingerprint. (The fingerprint is a long string, usually
260 written as 10 groups of 4 hexadecimal digits).
261 You can give this option multiple times. If you have multiple
263 source URLs, then you can have either no fingerprint, one
264 fingerprint or multiple fingerprints. If you have multiple, then
265 each must correspond 1-1 with a source URL.
266 --format qcow2
268 --format raw
269 For ordinary builds, this selects the output format. The default
270 is raw.
271 With --get-kernel this specifies the input format.
273 To create an old-style qcow2 file (for compatibility with RHEL 6 or
275 very old qemu < 1.1), after running virt-builder, use this command:
276 qemu-img amend -f qcow2 -o compat=0.10 output.qcow2
278 --get-kernel IMAGE
280 This option extracts the kernel and initramfs from a previously
281 built disk image called "IMAGE" (in fact it works for any VM disk
282 image, not just ones built using virt-builder).
283 Note this method is deprecated: there is a separate tool for this,
285 virt-get-kernel(1), which has more options for the file extraction.
286 The kernel and initramfs are written to the current directory,
288 unless you also specify the --output "outputdir" directory name.
289 The format of the disk image is automatically detected unless you
291 specify it by using the --format option.
292 In the case where the guest contains multiple kernels, the one with
294 the highest version number is chosen. To extract arbitrary kernels
295 from the disk image, see guestfish(1). To extract the entire /boot
296 directory of a guest, see virt-copy-out(1).
297 --gpg GPG
299 Specify an alternate gpg(1) (GNU Privacy Guard) binary. By default
300 virt-builder looks for either "gpg2" or "gpg" in the $PATH.
301 You can also use this to add gpg parameters, for example to specify
303 an alternate home directory:
304 virt-builder --gpg "gpg --homedir /tmp" [...]
306 -l [os-version]
308 --list [os-version]
309 --list --list-format format [os-version]
310 --list --long [os-version]
311 List all the available templates if no guest is specified, or only
312 for the specified one.
313 It is possible to choose with --list-format the output format for
315 the list templates:
316 short
318 The default format, prints only the template identifier and,
319 next to it, its short description.
320 long
322 Prints a textual list with the details of the available
323 sources, followed by the details of the available templates.
324 json
326 Prints a JSON object with the details of the available sources
327 and the details of the available templates.
328 The "version" key in the main object represents the
330 "compatibility version", and it is bumped every time the
331 resulting JSON output is incompatible with the previous
332 versions (for example the structure has changed, or non-
333 optional keys are no more present).
334 --long is a shorthand for the "long" format.
336 See also: --source, --notes, "SOURCES OF TEMPLATES".
338 --machine-readable
340 --machine-readable=format
341 This option is used to make the output more machine friendly when
342 being parsed by other programs. See "MACHINE READABLE OUTPUT"
343 below.
344 -m MB
346 --memsize MB
347 Change the amount of memory allocated to --run scripts. Increase
348 this if you find that --run scripts or the --install option are
349 running out of memory.
350 The default can be found with this command:
352 guestfish get-memsize
354 --network
356 --no-network
357 Enable or disable network access from the guest during the
358 installation.
359 Enabled is the default. Use --no-network to disable access.
361 The network only allows outgoing connections and has other minor
363 limitations. See "NETWORK" in virt-rescue(1).
364 If you use --no-network then certain other options such as
366 --install will not work.
367 This does not affect whether the guest can access the network once
369 it has been booted, because that is controlled by your hypervisor
370 or cloud environment and has nothing to do with virt-builder.
371 Generally speaking you should not use --no-network. But here are
373 some reasons why you might want to:
374 1. Because the libguestfs backend that you are using doesn't
376 support the network. (See: "BACKEND" in guestfs(3)).
377 2. Any software you need to install comes from an attached ISO, so
379 you don't need the network.
380 3. You don’t want untrusted guest code trying to access your host
382 network when running virt-builder. This is particularly an
383 issue when you don't trust the source of the operating system
384 templates. (See "SECURITY" below).
385 4. You don’t have a host network (eg. in secure/restricted
387 environments).
388 --no-sync
390 Do not sync the output file on exit.
391 Virt-builder "fsync"s the output file or disk image when it exits.
393 The reason is that qemu/KVM’s default caching mode is "none" or
395 "directsync", both of which bypass the host page cache. Therefore
396 these would not work correctly if you immediately started the guest
397 after running virt-builder - they would not see the complete output
398 file. (Note that you should not use these caching modes - they are
399 fundamentally broken for this and other reasons.)
400 If you are not using these broken caching modes, you can use
402 --no-sync to avoid this unnecessary sync and gain considerable
403 extra performance.
404 --notes os-version
406 List any notes associated with this guest, then exit (this does not
407 do the install).
408 -o filename
410 --output filename
411 Write the output to filename. If you don’t specify this option,
412 then the output filename is generated by taking the "os-version"
413 string and adding ".img" (for raw format) or ".qcow2" (for qcow2
414 format).
415 Note that the output filename could be a device, partition or
417 logical volume.
418 When used with --get-kernel, this option specifies the output
420 directory.
421 --print-cache
423 Print information about the template cache. See "CACHING".
424 -q
426 --quiet
427 Don’t print ordinary progress messages.
428 --size SIZE
430 Select the size of the output disk, where the size can be specified
431 using common names such as "32G" (32 gigabytes) etc.
432 Virt-builder will resize filesystems inside the disk image
434 automatically.
435 If the size is not specified, then one of two things happens. If
437 the output is a file, then the size is the same as the template.
438 If the output is a device, partition, etc then the size of that
439 device is used.
440 To specify size in bytes, the number must be followed by the
442 lowercase letter b, eg: "--size 10737418240b".
443 --smp N
445 Enable N ≥ 2 virtual CPUs for --run scripts to use.
446 --source URL
448 Set the source URL to look for indexes.
449 You can give this option multiple times to specify multiple
451 sources.
452 See also "SOURCES OF TEMPLATES" below.
454 Note that you should not point --source to sources that you don’t
456 trust (unless the source is signed by someone you do trust). See
457 also the --no-network option.
458 --no-warn-if-partition
460 Do not emit a warning if the output device is a partition. This
461 warning avoids a common user error when writing to a USB key or
462 external drive, when you should normally write to the whole device
463 (--output /dev/sdX), not to a partition on the device
464 (--output /dev/sdX1). Use this option to suppress this warning.
465 -v
467 --verbose
468 Enable debug messages and/or produce verbose output.
469 When reporting bugs, use this option and attach the complete output
471 to your bug report.
472 -V
474 --version
475 Display version number and exit.
476 -x Enable tracing of libguestfs API calls.
478 Customization options
480 --append-line FILE:LINE
481 Append a single line of text to the "FILE". If the file does not
482 already end with a newline, then one is added before the appended
483 line. Also a newline is added to the end of the "LINE" string
484 automatically.
485 For example (assuming ordinary shell quoting) this command:
487 --append-line '/etc/hosts:10.0.0.1 foo'
489 will add either "10.0.0.1 foo⏎" or "⏎10.0.0.1 foo⏎" to the file,
491 the latter only if the existing file does not already end with a
492 newline.
493 "⏎" represents a newline character, which is guessed by looking at
495 the existing content of the file, so this command does the right
496 thing for files using Unix or Windows line endings. It also works
497 for empty or non-existent files.
498 To insert several lines, use the same option several times:
500 --append-line '/etc/hosts:10.0.0.1 foo'
502 --append-line '/etc/hosts:10.0.0.2 bar'
503 To insert a blank line before the appended line, do:
505 --append-line '/etc/hosts:'
507 --append-line '/etc/hosts:10.0.0.1 foo'
508 --chmod PERMISSIONS:FILE
510 Change the permissions of "FILE" to "PERMISSIONS".
511 Note: "PERMISSIONS" by default would be decimal, unless you prefix
513 it with 0 to get octal, ie. use 0700 not 700.
514 --commands-from-file FILENAME
516 Read the customize commands from a file, one (and its arguments)
517 each line.
518 Each line contains a single customization command and its
520 arguments, for example:
521 delete /some/file
523 install some-package
524 password some-user:password:its-new-password
525 Empty lines are ignored, and lines starting with "#" are comments
527 and are ignored as well. Furthermore, arguments can be spread
528 across multiple lines, by adding a "\" (continuation character) at
529 the of a line, for example
530 edit /some/file:\
532 s/^OPT=.*/OPT=ok/
533 The commands are handled in the same order as they are in the file,
535 as if they were specified as --delete /some/file on the command
536 line.
537 --copy SOURCE:DEST
539 Copy files or directories recursively inside the guest.
540 Wildcards cannot be used.
542 --copy-in LOCALPATH:REMOTEDIR
544 Copy local files or directories recursively into the disk image,
545 placing them in the directory "REMOTEDIR" (which must exist).
546 Wildcards cannot be used.
548 --delete PATH
550 Delete a file from the guest. Or delete a directory (and all its
551 contents, recursively).
552 You can use shell glob characters in the specified path. Be
554 careful to escape glob characters from the host shell, if that is
555 required. For example:
556 virt-customize --delete '/var/log/*.log'.
558 See also: --upload, --scrub.
560 --edit FILE:EXPR
562 Edit "FILE" using the Perl expression "EXPR".
563 Be careful to properly quote the expression to prevent it from
565 being altered by the shell.
566 Note that this option is only available when Perl 5 is installed.
568 See "NON-INTERACTIVE EDITING" in virt-edit(1).
570 --firstboot SCRIPT
572 Install "SCRIPT" inside the guest, so that when the guest first
573 boots up, the script runs (as root, late in the boot process).
574 The script is automatically chmod +x after installation in the
576 guest.
577 The alternative version --firstboot-command is the same, but it
579 conveniently wraps the command up in a single line script for you.
580 You can have multiple --firstboot options. They run in the same
582 order that they appear on the command line.
583 Please take a look at "FIRST BOOT SCRIPTS" for more information and
585 caveats about the first boot scripts.
586 See also --run.
588 --firstboot-command 'CMD+ARGS'
590 Run command (and arguments) inside the guest when the guest first
591 boots up (as root, late in the boot process).
592 You can have multiple --firstboot options. They run in the same
594 order that they appear on the command line.
595 Please take a look at "FIRST BOOT SCRIPTS" for more information and
597 caveats about the first boot scripts.
598 See also --run.
600 --firstboot-install PKG,PKG..
602 Install the named packages (a comma-separated list). These are
603 installed when the guest first boots using the guest’s package
604 manager (eg. apt, yum, etc.) and the guest’s network connection.
605 For an overview on the different ways to install packages, see
607 "INSTALLING PACKAGES".
608 --hostname HOSTNAME
610 Set the hostname of the guest to "HOSTNAME". You can use a dotted
611 hostname.domainname (FQDN) if you want.
612 --install PKG,PKG..
614 Install the named packages (a comma-separated list). These are
615 installed during the image build using the guest’s package manager
616 (eg. apt, yum, etc.) and the host’s network connection.
617 For an overview on the different ways to install packages, see
619 "INSTALLING PACKAGES".
620 See also --update, --uninstall.
622 --link TARGET:LINK[:LINK..]
624 Create symbolic link(s) in the guest, starting at "LINK" and
625 pointing at "TARGET".
626 --mkdir DIR
628 Create a directory in the guest.
629 This uses "mkdir -p" so any intermediate directories are created,
631 and it also works if the directory already exists.
632 --move SOURCE:DEST
634 Move files or directories inside the guest.
635 Wildcards cannot be used.
637 --no-logfile
639 Scrub "builder.log" (log file from build commands) from the image
640 after building is complete. If you don't want to reveal precisely
641 how the image was built, use this option.
642 See also: "LOG FILE".
644 --password USER:SELECTOR
646 Set the password for "USER". (Note this option does not create the
647 user account).
648 See "USERS AND PASSWORDS" for the format of the "SELECTOR" field,
650 and also how to set up user accounts.
651 --password-crypto md5|sha256|sha512
653 When the virt tools change or set a password in the guest, this
654 option sets the password encryption of that password to "md5",
655 "sha256" or "sha512".
656 "sha256" and "sha512" require glibc ≥ 2.7 (check crypt(3) inside
658 the guest).
659 "md5" will work with relatively old Linux guests (eg. RHEL 3), but
661 is not secure against modern attacks.
662 The default is "sha512" unless libguestfs detects an old guest that
664 didn't have support for SHA-512, in which case it will use "md5".
665 You can override libguestfs by specifying this option.
666 Note this does not change the default password encryption used by
668 the guest when you create new user accounts inside the guest. If
669 you want to do that, then you should use the --edit option to
670 modify "/etc/sysconfig/authconfig" (Fedora, RHEL) or
671 "/etc/pam.d/common-password" (Debian, Ubuntu).
672 --root-password SELECTOR
674 Set the root password.
675 See "USERS AND PASSWORDS" for the format of the "SELECTOR" field,
677 and also how to set up user accounts.
678 Note: In virt-builder, if you don't set --root-password then the
680 guest is given a random root password.
681 --run SCRIPT
683 Run the shell script (or any program) called "SCRIPT" on the disk
684 image. The script runs virtualized inside a small appliance,
685 chrooted into the guest filesystem.
686 The script is automatically chmod +x.
688 If libguestfs supports it then a limited network connection is
690 available but it only allows outgoing network connections. You can
691 also attach data disks (eg. ISO files) as another way to provide
692 data (eg. software packages) to the script without needing a
693 network connection (--attach). You can also upload data files
694 (--upload).
695 You can have multiple --run options. They run in the same order
697 that they appear on the command line.
698 See also: --firstboot, --attach, --upload.
700 --run-command 'CMD+ARGS'
702 Run the command and arguments on the disk image. The command runs
703 virtualized inside a small appliance, chrooted into the guest
704 filesystem.
705 If libguestfs supports it then a limited network connection is
707 available but it only allows outgoing network connections. You can
708 also attach data disks (eg. ISO files) as another way to provide
709 data (eg. software packages) to the script without needing a
710 network connection (--attach). You can also upload data files
711 (--upload).
712 You can have multiple --run-command options. They run in the same
714 order that they appear on the command line.
715 See also: --firstboot, --attach, --upload.
717 --scrub FILE
719 Scrub a file from the guest. This is like --delete except that:
720 • It scrubs the data so a guest could not recover it.
722 • It cannot delete directories, only regular files.
724 --selinux-relabel
726 Relabel files in the guest so that they have the correct SELinux
727 label.
728 This will attempt to relabel files immediately, but if the
730 operation fails this will instead touch /.autorelabel on the image
731 to schedule a relabel operation for the next time the image boots.
732 You should only use this option for guests which support SELinux.
734 --sm-attach SELECTOR
736 Attach to a pool using "subscription-manager".
737 See "SUBSCRIPTION-MANAGER" for the format of the "SELECTOR" field.
739 --sm-credentials SELECTOR
741 Set the credentials for "subscription-manager".
742 See "SUBSCRIPTION-MANAGER" for the format of the "SELECTOR" field.
744 --sm-register
746 Register the guest using "subscription-manager".
747 This requires credentials being set using --sm-credentials.
749 --sm-remove
751 Remove all the subscriptions from the guest using
752 "subscription-manager".
753 --sm-unregister
755 Unregister the guest using "subscription-manager".
756 --ssh-inject USER[:SELECTOR]
758 Inject an ssh key so the given "USER" will be able to log in over
759 ssh without supplying a password. The "USER" must exist already in
760 the guest.
761 See "SSH KEYS" for the format of the "SELECTOR" field.
763 You can have multiple --ssh-inject options, for different users and
765 also for more keys for each user.
766 --timezone TIMEZONE
768 Set the default timezone of the guest to "TIMEZONE". Use a
769 location string like "Europe/London"
770 --touch FILE
772 This command performs a touch(1)-like operation on "FILE".
773 --truncate FILE
775 This command truncates "FILE" to a zero-length file. The file must
776 exist already.
777 --truncate-recursive PATH
779 This command recursively truncates all files under "PATH" to zero-
780 length.
781 --uninstall PKG,PKG..
783 Uninstall the named packages (a comma-separated list). These are
784 removed during the image build using the guest’s package manager
785 (eg. apt, yum, etc.). Dependent packages may also need to be
786 uninstalled to satisfy the request.
787 See also --install, --update.
789 --update
791 Do the equivalent of "yum update", "apt-get upgrade", or whatever
792 command is required to update the packages already installed in the
793 template to their latest versions.
794 See also --install, --uninstall.
796 --upload FILE:DEST
798 Upload local file "FILE" to destination "DEST" in the disk image.
799 File owner and permissions from the original are preserved, so you
800 should set them to what you want them to be in the disk image.
801 "DEST" could be the final filename. This can be used to rename the
803 file on upload.
804 If "DEST" is a directory name (which must already exist in the
806 guest) then the file is uploaded into that directory, and it keeps
807 the same name as on the local filesystem.
808 See also: --mkdir, --delete, --scrub.
810 --write FILE:CONTENT
812 Write "CONTENT" to "FILE".
813
815 INSTALLING PACKAGES
816 There are several approaches to installing packages or applications in
817 the guest which have different trade-offs.
818 Installing packages at build time
820 If the guest OS you are installing is similar to the host OS (eg. both
822 are Linux), and if libguestfs supports network connections, then you
823 can use --install to install packages like this:
824 virt-builder fedora-27 --install inkscape
826 This uses the guest’s package manager and the host’s network
828 connection.
829 Updating packages at build time
831 To update the installed packages in the template at build time:
833 virt-builder fedora-27 --update
835 Most of the templates that ship with virt-builder come with a very
837 minimal selection of packages (known as a "JEOS" or "Just Enough
838 Operating System"), which are up to date at the time the template is
839 created, but could be out of date by the time you come to install an OS
840 from the template. This option updates those template packages.
841 Installing packages at first boot
843 Another option is to install the packages when the guest first boots:
845 virt-builder fedora-27 --firstboot-install inkscape
847 This uses the guest’s package manager and the guest’s network
849 connection.
850 The downsides are that it will take the guest a lot longer to boot
852 first time, and there’s nothing much you can do if package installation
853 fails (eg. if a network problem means the guest can't reach the package
854 repositories).
855 Installing packages at build time from a side repository
857 If the software you want to install is not available in the main
859 package repository of the guest, then you can add a side repository.
860 Usually this is presented as an ISO (CD disk image) file containing
861 extra packages.
862 You can create the disk image using either genisoimage(1) or
864 virt-make-fs(1). For genisoimage, use a command like this:
865 genisoimage -o extra-packages.iso -R -J -V EXTRA cdcontents/
867 Create a script that mounts the ISO and sets up the repository. For
869 dnf, create /tmp/install.sh containing:
870 mkdir /tmp/mount
872 mount LABEL=EXTRA /tmp/mount
873 cat <<'EOF' > /etc/yum.repos.d/extra.repo
875 [extra]
876 name=extra
877 baseurl=file:///tmp/mount
878 enabled=1
879 EOF
880 dnf -y install famousdatabase
882 For apt, create /tmp/install.sh containing:
884 mkdir /tmp/mount
886 mount LABEL=EXTRA /tmp/mount
887 apt-cdrom -d=/tmp/mount add
889 apt-get -y install famousdatabase
890 Use the --attach option to attach the CD / disk image and the --run
892 option to run the script:
893 virt-builder fedora-27 \
895 --attach extra-packages.iso \
896 --run /tmp/install.sh
897 USERS AND PASSWORDS
899 The --root-password option is used to change the root password
900 (otherwise a random password is used). This option takes a password
901 "SELECTOR" in one of the following formats:
902 --root-password file:FILENAME
904 Read the root password from "FILENAME". The whole first line of
905 this file is the replacement password. Any other lines are
906 ignored. You should create the file with mode 0600 to ensure no
907 one else can read it.
908 --root-password password:PASSWORD
910 Set the root password to the literal string "PASSWORD".
911 Note: this is not secure since any user on the same machine can see
913 the cleartext password using ps(1).
914 --root-password random
916 Choose a random password, which is printed on stdout. The password
917 has approximately 120 bits of randomness.
918 This is the default.
920 --root-password disabled
922 The root account password is disabled. This is like putting "*" in
923 the password field.
924 --root-password locked:file:FILENAME
926 --root-password locked:password:PASSWORD
927 --root-password locked:random
928 The root account is locked, but a password is placed on the
929 account. If first unlocked (using "passwd -u") then logins will
930 use the given password.
931 --root-password locked
933 --root-password locked:disabled
934 The root account is locked and password is disabled.
935 Creating user accounts
937 To create user accounts, use the useradd(8) command with
939 --firstboot-command like this:
940 virt-builder --firstboot-command \
942 'useradd -m -p "" rjones ; chage -d 0 rjones'
943 The above command will create an "rjones" account with no password, and
945 force the user to set a password when they first log in. There are
946 other ways to manage passwords, see useradd(8) for details.
947 KEYBOARD LAYOUT
949 Because there are so many different ways to set the keyboard layout in
950 Linux distributions, virt-builder does not yet attempt to have a simple
951 command line option. This section describes how to set the keyboard
952 for some common Linux distributions.
953 Keyboard layout with systemd
955 For distros that use systemd "localectl", use a command like this:
957 virt-builder fedora-27 \
959 --firstboot-command 'localectl set-keymap uk'
960 See localectl(1) and
962 https://www.happyassassin.net/2013/11/23/keyboard-layouts-in-fedora-20-and-previously/
963 for more details.
964 Keyboard layout using /etc/sysconfig/keyboard
966 For RHEL ≤ 6, Fedora ≤ 18 and similar, upload or modify the keyboard
968 configuration file using the --upload, --write or --edit options. For
969 example:
970 virt-builder centos-6 \
972 --edit '/etc/sysconfig/keyboard: s/^KEYTABLE=.*/KEYTABLE="uk"/'
973 The format of this file can be found documented in many places online.
975 Keyboard layout with Debian-derived distros
977 For Debian-derived distros using /etc/default/keyboard, upload or
979 modify the keyboard file using the --upload, --write or --edit options.
980 For example:
981 virt-builder debian-8 \
983 --edit '/etc/default/keyboard: s/^XKBLAYOUT=.*/XKBLAYOUT="gb"/'
984 See https://wiki.debian.org/Keyboard.
986 LANGUAGE
988 Most Linux distributions support multiple locale settings so that you
989 can have guest messages printed in another language such as Russian.
990 However there is no single setting which controls this, since extra
992 packages may need to be installed to support console and X fonts, and
993 keyboard input methods. The packages required, and their configuration
994 is highly distro-specific, and it is outside the scope of virt-builder
995 to do this.
996 This section contains examples for some common Linux distributions.
998 Setting Japanese in Fedora 25
1000 virt-builder fedora-27 \
1002 --size 20G \
1003 --update \
1004 --install @japanese-support \
1005 --install @xfce \
1006 --install xorg-x11-server-Xorg,xorg-x11-drivers,rsyslog \
1007 --link /usr/lib/systemd/system/graphical.target:/etc/systemd/system/default.target \
1008 --firstboot-command 'localectl set-locale LANG=ja_JP.utf8' \
1009 --firstboot-command 'localectl set-keymap jp' \
1010 --firstboot-command 'systemctl isolate graphical.target'
1011 Setting Japanese in Debian 8 (Jessie)
1013 Note that although this enables Japanese in the text console too, it is
1015 unlikely that you will see properly rendered Japanese there. However
1016 Japanese is properly rendered in X applications and terminals.
1017 pkgs=locales,xfce4,\
1019 ibus,ibus-anthy,\
1020 fonts-ipafont-gothic,fonts-ipafont-mincho,\
1021 fonts-takao-mincho,\
1022 xfonts-intl-japanese,xfonts-intl-japanese-big,\
1023 iceweasel-l10n-ja,manpages-ja
1024 virt-builder debian-8 \
1026 --size 20G \
1027 --install $pkgs \
1028 --edit '/etc/locale.gen: s,^#\s*ja,ja,' \
1029 --write '/etc/default/locale:LANG="ja_JP.UTF-8"' \
1030 --run-command "locale-gen"
1031 LOG FILE
1033 Scripts and package installation that runs at build time (--run,
1034 --run-command, --install, --update, but not firstboot) is logged in one
1035 of the following locations:
1036 /tmp/builder.log
1038 On Linux, BSD, and other non-Windows guests.
1039 C:\Temp\builder.log
1041 On Windows, DOS guests.
1042 /builder.log
1044 If /tmp or C:\Temp is missing.
1045 If you don’t want the log file to appear in the final image, then use
1047 the --no-logfile command line option.
1048 SSH KEYS
1050 The --ssh-inject option is used to inject ssh keys for users in the
1051 guest, so they can login without supplying a password.
1052 The "SELECTOR" part of the option value is optional; in this case,
1054 --ssh-inject "USER" means that we look in the current user’s ~/.ssh
1055 directory to find the default public ID file. That key is uploaded.
1056 "default public ID" is the default_ID_file file described in
1057 ssh-copy-id(1).
1058 If specified, the "SELECTOR" can be in one of the following formats:
1060 --ssh-inject USER:file:FILENAME
1062 Read the ssh key from FILENAME. FILENAME is usually a .pub file.
1063 --ssh-inject USER:string:KEY_STRING
1065 Use the specified "KEY_STRING". "KEY_STRING" is usually a public
1066 string like ssh-rsa AAAA.... user@localhost.
1067 In any case, the ~USER/.ssh directory and the
1069 ~USER/.ssh/authorized_keys file will be created if not existing
1070 already.
1071 FIRST BOOT SCRIPTS
1073 The --firstboot and --firstboot-command options allow you to execute
1074 commands at the first boot of the guest. To do so, an init script for
1075 the guest init system is installed, which takes care of running all the
1076 added scripts and commands.
1077 Supported operating systems are:
1079 Linux
1081 Init systems supported are: systemd, System-V init (known also as
1082 sysvinit), and Upstart (using the System-V scripts).
1083 Note that usually init scripts run as root, but with a more limited
1085 environment than what could be available from a normal shell: for
1086 example, $HOME may be unset or empty.
1087 The output of the first boot scripts is available in the guest as
1089 ~root/virt-sysprep-firstboot.log.
1090 Windows
1092 rhsrvany.exe, available from sources at
1093 https://github.com/rwmjones/rhsrvany, or pvvxsvc.exe, available
1094 with SUSE VMDP is installed to run the first boot scripts. It is
1095 required, and the setup of first boot scripts will fail if it is
1096 not present.
1097 rhsrvany.exe or pvvxsvc.exe is copied from the location pointed to
1099 by the "VIRT_TOOLS_DATA_DIR" environment variable; if not set, a
1100 compiled-in default will be used (something like
1101 /usr/share/virt-tools).
1102 The output of the first boot scripts is available in the guest as
1104 C:\Program Files\Guestfs\Firstboot\log.txt.
1105 SUBSCRIPTION-MANAGER
1107 It is possible to automate the registration and attaching of the system
1108 using "subscription-manager". This is typical on Red Hat Enterprise
1109 Linux guests. There are few options which ease this process, avoid
1110 executing commands manually and exposing passwords on command line.
1111 --sm-register starts the registration process, and requires
1113 --sm-credentials to be specified; the format of the "SELECTOR" of
1114 --sm-credentials is one of the following formats:
1115 --sm-credentials USER:file:FILENAME
1117 Read the password for the specified "USER" from FILENAME.
1118 --sm-credentials USER:password:PASSWORD
1120 Use the literal string "PASSWORD" for the specified "USER".
1121 --sm-attach attaches the system to subscriptions; the format of its
1123 "SELECTOR" is one of the following:
1124 --sm-attach auto
1126 "subscription-manager" attaches to the best-fitting subscriptions
1127 for the system.
1128 --sm-attach file:FILENAME
1130 Read the pool ID from FILENAME.
1131 --sm-attach pool:POOL
1133 Use the literal string "POOL" as pool ID.
1134 --sm-remove removes all the subscriptions from the guest, while
1136 --sm-unregister completely unregister the system.
1137 INSTALLATION PROCESS
1139 When you invoke virt-builder, installation proceeds as follows:
1140 • The template image is downloaded.
1142 If the template image is present in the cache, the cached version
1144 is used instead. (See "CACHING").
1145 • The template signature is checked.
1147 • The template is uncompressed to a tmp file.
1149 • The template image is resized into the destination, using
1151 virt-resize(1).
1152 • Extra disks are attached (--attach).
1154 • A new random seed is generated for the guest.
1156 • Guest customization is performed, in the order specified on the
1158 command line.
1159 • SELinux relabelling is done (--selinux-relabel).
1161 IMPORTING THE DISK IMAGE
1163 Importing into libvirt
1164 Import the disk image into libvirt using virt-install(1) --import
1166 option.
1167 virt-install --import \
1169 --name guest --ram 2048 \
1170 --disk path=disk.img,format=raw --os-variant fedora27
1171 Notes:
1173 1. You must specify the correct format. The format is "raw" unless
1175 you used virt-builder’s --format option.
1176 2. --os-variant is highly recommended, because it will present optimum
1178 devices to enable the guest to run most efficiently. To get a list
1179 of all variants, do:
1180 osinfo-query os
1182 The above tool is provided by libosinfo package.
1184 3. You can run virt-install as root or non-root. Each works slightly
1186 differently because libvirt manages a different set of virtual
1187 machines for each user. In particular virt-manager normally shows
1188 the root-owned VMs, whereas Boxes shows the user-owned VMs, and
1189 other tools probably work differently as well.
1190 Importing into OpenStack
1192 Import the image into Glance (the OpenStack image store) by doing:
1194 glance image-create --name fedora-27-image --file fedora-27.img \
1196 --disk-format raw --container-format bare \
1197 --is-public True
1198 The --file parameter is the virt-builder-generated disk image. It
1200 should match virt-builder’s --output option. The --disk-format
1201 parameter should match virt-builder’s --format option (or "raw" if you
1202 didn't use that option). The --container-format should always be
1203 "bare" since virt-builder doesn't put images into containers.
1204 You can use the "glance image-show fedora-27-image" command to display
1206 the properties of the image.
1207 To boot up an instance of your image on a Nova compute node, do:
1209 nova boot fedora-27-server --image fedora-27-image \
1211 --flavor m1.medium
1212 Use "nova flavor-list" to list possible machine flavors. Use
1214 "nova list" to list running instances.
1215 Booting directly using qemu or KVM
1217 The qemu command line is not very stable or easy to use, hence libvirt
1219 should be used if possible. However a command line similar to the
1220 following could be used to boot the virtual machine:
1221 qemu-system-x86_64 \
1223 -machine accel=kvm:tcg \
1224 -cpu host \
1225 -m 2048 \
1226 -drive file=disk.img,format=raw,if=virtio
1227 As with libvirt, it is very important that the correct format is
1229 chosen. It will be "raw" unless the --format option was used.
1230 CONFIGURATION MANAGEMENT
1232 Puppet
1233 To enable the Puppet agent in a guest, install the package, point the
1235 configuration at your Puppetmaster, and ensure the agent runs at boot.
1236 A typical virt-builder command would be:
1238 virt-builder fedora-27 \
1240 --hostname client.example.com \
1241 --update \
1242 --install puppet \
1243 --append-line '/etc/puppet/puppet.conf:[agent]' \
1244 --append-line '/etc/puppet/puppet.conf:server = puppetmaster.example.com/' \
1245 --run-command 'systemctl enable puppet' \
1246 --selinux-relabel
1247 The precise instructions vary according to the Linux distro. For
1249 further information see:
1250 https://docs.puppet.com/puppet/latest/install_pre.html
1251 DEBUGGING BUILDS
1253 If virt-builder itself fails, then enable debugging (-v) and report a
1254 bug (see "BUGS" below).
1255 If virt-builder fails because some script or package it is installing
1257 fails, try using --no-delete-on-failure to preserve the output file,
1258 and continue reading this section.
1259 If virt-builder is successful but the image doesn't work, here are some
1261 things to try:
1262 Use virt-rescue
1264 Run virt-rescue(1) on the disk image:
1265 virt-rescue -a disk.img
1267 This gives you a rescue shell. You can mount the filesystems from
1269 the disk image on /sysroot and examine them using ordinary Linux
1270 commands. You can also chroot into the guest to reinstall the
1271 bootloader. The virt-rescue man page has a lot more information
1272 and examples.
1273 Use guestfish
1275 Run guestfish(1) on the disk image:
1276 guestfish -a disk.img -i
1278 Use guestfish commands like "ll /directory" and "cat /file" to
1280 examine directories and files.
1281 Use guestmount
1283 Mount the disk image safely on the host using FUSE and
1284 guestmount(1):
1285 mkdir /tmp/mp
1287 guestmount -a disk.img -i /tmp/mp
1288 cd /tmp/mp
1289 To unmount the disk image do:
1291 fusermount -u /tmp/mp
1293 Add a serial console
1295 If the guest hangs during boot, it can be helpful to add a serial
1296 console to the guest, and direct kernel messages to the serial
1297 console. Adding the serial console will involve looking at the
1298 documentation for your hypervisor. To direct kernel messages to
1299 the serial console, add the following on the kernel command line:
1300 console=tty0 console=ttyS0,115200
1302 SOURCES OF TEMPLATES
1304 virt-builder reads the available sources from configuration files, with
1305 the .conf extension and located in the following paths:
1306 • $XDG_CONFIG_HOME/virt-builder/repos.d/ ($XDG_CONFIG_HOME is
1308 $HOME/.config if not set).
1309 • $VIRT_BUILDER_DIRS/virt-builder/repos.d/ (where $VIRT_BUILDER_DIRS
1311 means any of the directories in that environment variable, or just
1312 /etc if not set).
1313 Each .conf file in those paths has a simple text format like the
1315 following:
1316 [libguestfs.org]
1318 uri=http://libguestfs.org/download/builder/index.asc
1319 gpgkey=file:///etc/xdg/virt-builder/repos.d/libguestfs.gpg
1320 The part in square brackets is the repository identifier, which is used
1322 as unique identifier.
1323 The following fields can appear:
1325 "uri=URI"
1327 The URI of the index file which this repository refers to.
1328 This field is required.
1330 "gpgkey=URI"
1332 This optional field represents the URI (although only file:// URIs
1333 are accepted) of the key used to sign the index file. If not
1334 present, the index file referred by uri=.. is not signed.
1335 "proxy=MODE"
1337 This optional field specifies the proxy mode, to be used when
1338 downloading the index file of this repository. The possible values
1339 are:
1340 no, off
1342 No proxy is being used at all, even overriding the system
1343 configuration.
1344 system
1346 The proxy used is the system one.
1347 anything else
1349 Specifies the actual proxy configuration to be used, overriding
1350 the system configuration.
1351 If not present, the assumed value is to respect the proxy settings
1353 of the system (i.e. as if system would be specified).
1354 "format=FORMAT"
1356 This optional field specifies the format of the repository. The
1357 possible values are:
1358 native
1360 The native format of the "virt-builder" repository. See also
1361 "Creating and signing the index file" below.
1362 simplestreams
1364 The URI represents the root of a Simple Streams v1.0 tree of
1365 metadata.
1366 For more information about Simple Streams, see also
1368 https://launchpad.net/simplestreams.
1369 If not present, the assumed value is "native".
1371 For serious virt-builder use, you may want to create your own
1373 repository of templates.
1374 Libguestfs.org repository
1376 Out of the box, virt-builder downloads the file
1378 http://libguestfs.org/download/builder/index.asc which is an index of
1379 available templates plus some information about each one, wrapped up in
1380 a digital signature. The command "virt-builder --list" lists out the
1381 information in this index file.
1382 The templates hosted on libguestfs.org were created using shell
1384 scripts, kickstart files and preseed files which can be found in the
1385 libguestfs source tree, in "builder/templates".
1386 Setting up the repository
1388 You can set up your own site containing an index file and some
1390 templates, and then point virt-builder at the site by creating a .conf
1391 file pointing to it.
1392 Note that if your index is signed, you will need to properly fill
1394 gpgkey=.. in your .conf file, making sure to deploy also the GPG key
1395 file.
1396 virt-builder --source https://example.com/builder/index.asc \
1398 --fingerprint 'AAAA BBBB ...' \
1399 --list
1400 You can host this on any web or FTP server, or a local or network
1402 filesystem.
1403 Setting up a GPG key
1405 If you don’t have a GnuPG key, you will need to set one up. (Strictly
1407 speaking this is optional, but if your index and template files are not
1408 signed then virt-builder users will have to use the
1409 --no-check-signature flag every time they use virt-builder.)
1410 To create a key, see the GPG manual
1412 http://www.gnupg.org/gph/en/manual.html.
1413 Export your GPG public key:
1415 gpg --export -a "you@example.com" > pubkey
1417 Create the templates
1419 There are many ways to create the templates. For example you could
1421 clone existing guests (see virt-sysprep(1)), or you could install a
1422 guest by hand (virt-install(1)). To see how the templates were created
1423 for virt-builder, look at the scripts in "builder/templates"
1424 Virt-builder supports any image format (e.g. raw, qcow2, etc) as
1426 template, both as-is, and compressed as XZ. This way, existing images
1427 (e.g. cleaned using virt-sysprep(1)) can be used as templates.
1428 For best results when compressing the templates, use the following xz
1430 options (see nbdkit-xz-plugin(1) for further explanation):
1431 xz --best --block-size=16777216 disk
1433 Creating and signing the index file
1435 The index file has a simple text format (shown here without the digital
1437 signature):
1438 [fedora-18]
1440 name=Fedora® 18
1441 osinfo=fedora18
1442 arch=x86_64
1443 file=fedora-18.xz
1444 checksum[sha512]=...
1445 format=raw
1446 size=6442450944
1447 compressed_size=148947524
1448 expand=/dev/sda3
1449 [fedora-19]
1451 name=Fedora® 19
1452 osinfo=fedora19
1453 arch=x86_64
1454 file=fedora-19.xz
1455 checksum[sha512]=...
1456 revision=3
1457 format=raw
1458 size=4294967296
1459 compressed_size=172190964
1460 expand=/dev/sda3
1461 The part in square brackets is the "os-version", which is the same
1463 string that is used on the virt-builder command line to build that OS.
1464 The index file creation and signature can be eased with the
1466 virt-builder-repository(1) tool.
1467 After preparing the "index" file in the correct format, clearsign it
1469 using the following command:
1470 gpg --clearsign --armor index
1472 This will create the final file called index.asc which can be uploaded
1474 to the server (and is the uri=.. URL). As noted above, signing the
1475 index file is optional, but recommended.
1476 The following fields can appear:
1478 "name=NAME"
1480 The user-friendly name of this template. This is displayed in the
1481 --list output but is otherwise not significant.
1482 "osinfo=ID"
1484 This optional field maps the operating system to the associated
1485 libosinfo ID. Virt-builder does not use it (yet).
1486 "arch=ARCH"
1488 The architecture of the operating system installed within the
1489 template. This field is required.
1490 "file=PATH"
1492 The path (relative to the index) of the xz-compressed template.
1493 Note that absolute paths or URIs are not permitted here. This is
1495 because virt-builder has a "same origin" policy for templates so
1496 they cannot come from other servers.
1497 "sig=PATH"
1499 This option is deprecated. Use the checksum field instead.
1500 The path (relative to the index) of the GPG detached signature of
1502 the xz file.
1503 Note that absolute paths or URIs are not permitted here. This is
1505 because virt-builder has a "same origin" policy for templates so
1506 they cannot come from other servers.
1507 The file can be created as follows:
1509 gpg --detach-sign --armor -o disk.xz.sig disk.xz
1511 "checksum[sha512]=7b882fe9b82eb0fef..."
1513 The SHA-512 checksum of the file specified in file=.. is checked
1514 after it is downloaded. To work out the signature, do:
1515 sha512sum disk.xz
1517 Note if you use this, you don’t need to sign the file, ie. don’t
1519 use "sig". This option overrides "sig".
1520 "checksum=7b882fe9b82eb0fef..."
1522 "checksum" is an alias for "checksum[sha512]".
1523 If you need to interoperate with virt-builder = 1.24.0 then you
1525 have to use "checksum" because that version would give a parse
1526 error with square brackets and numbers in the key of a field. This
1527 is fixed in virt-builder ≥ 1.24.1.
1528 "revision=N"
1530 The revision is an integer which is used to control the template
1531 cache. Increasing the revision number causes clients to download
1532 the template again even if they have a copy in the cache.
1533 The revision number is optional. If omitted it defaults to 1.
1535 "format=raw"
1537 "format=qcow2"
1538 Specify the format of the disk image; in case it is compressed,
1539 that is the format before the compression. If not given, the
1540 format is autodetected, but generally it is better to be explicit
1541 about the intended format.
1542 Note this is the source format, which is different from the
1544 --format option (requested output format). Virt-builder does on-
1545 the-fly conversion from the source format to the requested output
1546 format.
1547 "size=NNN"
1549 The virtual size of the image in bytes. This is the size of the
1550 image when uncompressed. If using a non-raw format such as qcow2
1551 then it means the virtual disk size, not the size of the qcow2
1552 file.
1553 This field is required.
1555 Virt-builder also uses this as the minimum size that users can
1557 request via the --size option, or as the default size if there is
1558 no --size option.
1559 "compressed_size=NNN"
1561 The actual size of the disk image in bytes, i.e. what was specified
1562 in file=... This is just used for information (when using "long",
1563 and "json" formats of --list).
1564 "expand=/dev/sdaX"
1566 When expanding the image to its final size, instruct virt-resize(1)
1567 to expand the named partition in the guest image to fill up all
1568 available space. This works like the virt-resize --expand option.
1569 You should usually put the device name of the guest’s root
1571 filesystem here.
1572 It’s a good idea to use this, but not required. If the field is
1574 omitted then virt-resize will create an extra partition at the end
1575 of the disk to cover the free space, which is much less user-
1576 friendly.
1577 "lvexpand=/dev/VolGroup/LogVol"
1579 When expanding the image to its final size, instruct virt-resize(1)
1580 to expand the named logical volume in the guest image to fill up
1581 all available space. This works like the virt-resize --lv-expand
1582 option.
1583 If the guest uses LVM2 you should usually put the LV of the guest’s
1585 root filesystem here. If the guest does not use LVM2 or its root
1586 filesystem is not on an LV, don't use this option.
1587 "notes=NOTES"
1589 Any notes that go with this image, especially notes describing what
1590 packages are in the image, how the image was prepared, and
1591 licensing information.
1592 This information is shown in the --notes and --list --long modes.
1594 You can use multi-line notes here by indenting each new line with
1596 at least one character of whitespace (even on blank lines):
1597 notes=This image was prepared using
1599 the following kickstart script:
1600 <-- one space at beginning of line
1601 part /boot --fstype ext3
1602 ...
1603 "hidden=true"
1605 Using the hidden flag prevents the template from being listed by
1606 the --list option (but it is still installable). This is used for
1607 test images.
1608 "aliases=ALIAS1 ALIAS2 ..."
1610 This optional field specifies a list of aliases, separated by
1611 spaces, for the image. For example, an alias could be used to
1612 always point to the latest version of a certain image, leaving the
1613 old versions available in the index instead of updating the same
1614 image (see the "revision" field).
1615 Running virt-builder against multiple sources
1617 It is possible to use multiple sources with virt-builder. The
1619 recommended way is to deploy .conf files pointing to the index files.
1620 Another way is to specify the sources using multiple --source and/or
1621 --fingerprint options:
1622 virt-builder \
1624 --source http://example.com/s1/index.asc \
1625 --source http://example.com/s2/index.asc
1626 You can provide N or 1 fingerprints. In the case where you provide N
1628 fingerprints, N = number of sources and there is a 1-1 correspondence
1629 between each source and each fingerprint:
1630 virt-builder \
1632 --source http://example.com/s1/index.asc --fingerprint '0123 ...' \
1633 --source http://example.com/s2/index.asc --fingerprint '9876 ...'
1634 In the case where you provide 1 fingerprint, the same fingerprint is
1636 used for all sources.
1637 You "must" provide at least 1 fingerprint.
1639 Licensing of templates
1641 You should be aware of the licensing of images that you distribute.
1643 For open source guests, provide a link to the source code in the
1644 "notes" field and comply with other requirements (eg. around
1645 trademarks).
1646 Formal specification of the index file
1648 The index file format has a formal specification defined by the flex
1650 scanner and bison parser used to parse the file. This can be found in
1651 the following files in the libguestfs source tree:
1652 builder/index-scan.l
1654 builder/index-parse.y
1655 A tool called virt-index-validate(1) is available to validate the index
1657 file to ensure it is correct.
1658 Note that the parser and tool can work on either the signed or unsigned
1660 index file (ie. index or index.asc).
1661 The index is always encoded in UTF-8.
1663 CACHING
1665 Caching templates
1666 Since the templates are usually very large, downloaded templates are
1668 cached in the user’s home directory.
1669 The location of the cache is $XDG_CACHE_HOME/virt-builder/ or
1671 $HOME/.cache/virt-builder.
1672 You can print out information about the cache directory, including
1674 which guests are currently cached, by doing:
1675 virt-builder --print-cache
1677 The cache can be deleted if you want to save space by doing:
1679 virt-builder --delete-cache
1681 You can download all (current) templates to the local cache by doing:
1683 virt-builder --cache-all-templates
1685 To disable the template cache, use --no-cache.
1687 Only templates are cached. The index and detached digital signatures
1689 are not cached.
1690 Caching packages
1692 Virt-builder uses curl(1) to download files and it also uses the
1694 current "http_proxy" (etc) settings when installing packages
1695 (--install, --update).
1696 You may therefore want to set those environment variables in order to
1698 maximize the amount of local caching that happens. See "ENVIRONMENT
1699 VARIABLES" and curl(1).
1700 Local mirrors
1702 To increase both speed and reliability of installing packages, you can
1704 set up a local mirror of the target distribution, and point the guest
1705 package manager at that.
1706 Using a local mirror with Fedora
1708 To install a Fedora guest using a local mirror:
1710 virt-builder fedora-27 \
1712 --edit '/etc/yum.repos.d/fedora.repo:
1713 s{.*baseurl=.*}{baseurl=http://example.com/mirror/};
1714 s{.*metalink=.*}{};
1715 ' \
1716 --edit '/etc/yum.repos.d/fedora-updates.repo:
1717 s{.*baseurl=.*}{baseurl=http://example.com/mirror-updates/};
1718 s{.*metalink=.*}{};
1719 ' \
1720 --run-command 'dnf -y update' \
1721 --install 'pkg1,pkg2,...'
1722 Using a local mirror with Debian
1724 Assuming that you are using "apt-proxy" to mirror the repository, you
1726 should create a new sources.list file to point to your proxy (see
1727 https://help.ubuntu.com/community/AptProxy) and then do:
1728 virt-builder debian-8 \
1730 --upload sources.list:/etc/apt/sources.list \
1731 --run-command 'apt-get -y update' \
1732 --install 'pkg1,pkg2,...'
1733 DIGITAL SIGNATURES
1735 Virt-builder uses GNU Privacy Guard (GnuPG or gpg) to verify that the
1736 index and templates have not been tampered with.
1737 The source points to an index file, which is optionally signed.
1739 Virt-builder downloads the index and checks that the signature is valid
1741 and the signer’s fingerprint matches the specified fingerprint (ie. the
1742 one specified in gpgkey=.. in the .conf, or with --fingerprint, in that
1743 order).
1744 For checking against the built-in public key/fingerprint, this requires
1746 importing the public key into the user’s local gpg keyring (that’s just
1747 the way that gpg works).
1748 When a template is downloaded, its signature is checked in the same
1750 way.
1751 Although the signatures are optional, if you don’t have them then virt-
1753 builder users will have to use --no-check-signature on the command
1754 line. This prevents an attacker from replacing the signed index file
1755 with an unsigned index file and having virt-builder silently work
1756 without checking the signature. In any case it is highly recommended
1757 that you always create signed index and templates.
1758 ARCHITECTURE
1760 Virt-builder can build a guest for any architecture no matter what the
1761 host architecture is. For example an x86-64 guest on an ARM host.
1762 However certain options may not work, specifically options that require
1764 running commands in the guest during the build process: --install,
1765 --update, --run, --run-command. You may need to replace these with
1766 their firstboot-equivalents.
1767 An x86-64 host building 32 bit i686 guests should work without any
1769 special steps.
1770 SECURITY
1772 Virt-builder does not need to run as root (in fact, should not be run
1773 as root), and doesn't use setuid, "sudo" or any similar mechanism.
1774 --install, --update, --run and --run-command are implemented using an
1776 appliance (a small virtual machine) so these commands do not run on the
1777 host. If you are using the libguestfs libvirt backend and have SELinux
1778 enabled then the virtual machine is additionally encapsulated in an
1779 SELinux container (sVirt).
1780 However these options will have access to the host’s network and since
1782 the template may contain untrusted code, the code might try to access
1783 host network resources which it should not. You can use --no-network
1784 to prevent this.
1785 Firstboot commands run in the context of the guest when it is booted,
1787 and so the security of your hypervisor / cloud should be considered.
1788 Virt-builder injects a random seed into every guest which it builds.
1790 This helps to ensure that TCP sequence numbers, UUIDs, ssh host keys
1791 etc are truly random when the guest boots.
1792 You should check digital signatures and not ignore any signing errors.
1794 CLONES
1796 If you wish to create many new guests of the same type, it is tempting
1797 to run virt-builder once and then copy the output file. You should not
1798 do this. You should run virt-builder once for each new guest you need.
1799 The reason is that each clone needs to have (at least) a separate
1801 random seed, and possibly other unique features (such as filesystem
1802 UUIDs) in future versions of virt-builder.
1803 Another thing you should not do is to boot the guest, then clone the
1805 booted disk image. The reason is that some guests create unique
1806 machine IDs, SSH host keys and so on at first boot, and you would not
1807 want clones to have duplicate identities.
1808 See also: virt-sysprep(1).
1810 PERFORMANCE
1812 The most important aspect of getting good performance is caching.
1813 Templates gets downloaded into the cache the first time they are used,
1814 or if you use the --cache-all-templates option. See "CACHING" above
1815 for further information.
1816 Packages required for the --install and --update options are downloaded
1818 using the host network connection. Setting the "http_proxy",
1819 "https_proxy" and "ftp_proxy" environment variables to point to a local
1820 web cache may ensure they only need to be downloaded once. You can
1821 also try using a local package repository, although this can be complex
1822 to set up and varies according to which Linux distro you are trying to
1823 install.
1824 Using --no-sync
1826 Use --no-sync. However read the caveats in the "OPTIONS" section
1828 above, since this can cause disk corruption if not used correctly.
1829 Skipping virt-resize
1831 Virt-builder can skip the virt-resize step under certain conditions.
1833 This makes virt-builder much faster. The conditions are:
1834 • the output must be a regular file (not a block device), and
1836 • the user did not use the --size option, and
1838 • the output format is the same as the template format (usually raw).
1840 pxzcat
1842 Virt-builder uses an internal implementation of pxzcat (parallel xzcat)
1844 if liblzma was found at build time. If liblzma was not found at build
1845 time, regular "xzcat" is used which is single-threaded.
1846 User-Mode Linux
1848 You can use virt-builder with the User-Mode Linux (UML) backend. This
1850 may be faster when running virt-builder inside a virtual machine (eg.
1851 in the cloud).
1852 To enable the UML backend, read the instructions in "USER-MODE LINUX
1854 BACKEND" in guestfs(3).
1855 Currently you have to use the --no-network option. This should be
1857 fixed in a future version.
1858 The qcow2 output format is not supported by UML. You can only create
1860 raw-format guests.
1861 SELINUX
1863 Guests which use SELinux (such as Fedora and Red Hat Enterprise Linux)
1864 require that each file has a correct SELinux label.
1865 Virt-builder does not know how to give new files a label, so there are
1867 two possible strategies it can use to ensure correct labelling:
1868 Using --selinux-relabel
1870 This runs setfiles(8) just before finalizing the guest, which sets
1871 SELinux labels correctly in the disk image.
1872 This is the recommended method.
1874 --touch /.autorelabel
1876 Guest templates may already contain a file called /.autorelabel or
1877 you may touch it.
1878 For guests that use SELinux, this causes restorecon(8) to run at
1880 first boot. Guests will reboot themselves once the first time you
1881 use them, which is normal and harmless.
1882 Please note that if your guest uses SELinux, and you are doing
1884 operations on it which might create new files or change existing ones,
1885 you are recommended to use --selinux-relabel. This will help in making
1886 sure that files have the right SELinux labels.
1887
1889 The --machine-readable option can be used to make the output more
1890 machine friendly, which is useful when calling virt-builder from other
1891 programs, GUIs etc.
1892 Use the option on its own to query the capabilities of the virt-builder
1894 binary. Typical output looks like this:
1895 $ virt-builder --machine-readable
1897 virt-builder
1898 arch
1899 config-file
1900 customize
1901 json-list
1902 pxzcat
1903 A list of features is printed, one per line, and the program exits with
1905 status 0.
1906 It is possible to specify a format string for controlling the output;
1908 see "ADVANCED MACHINE READABLE OUTPUT" in guestfs(3).
1909
1911 For other environment variables which affect all libguestfs programs,
1912 see "ENVIRONMENT VARIABLES" in guestfs(3).
1913 "http_proxy"
1915 "https_proxy"
1916 "no_proxy"
1917 Set the proxy for downloads. These environment variables (and
1918 more) are actually interpreted by curl(1), not virt-builder.
1919 "HOME"
1921 Used to determine the location of the template cache, and the
1922 location of the user' sources. See "CACHING" and "SOURCES OF
1923 TEMPLATES".
1924 "VIRT_TOOLS_DATA_DIR"
1926 This can point to the directory containing data files used for
1927 Windows firstboot installation.
1928 Normally you do not need to set this. If not set, a compiled-in
1930 default will be used (something like /usr/share/virt-tools).
1931 This directory may contain the following files:
1933 rhsrvany.exe
1935 This is the RHSrvAny Windows binary, used to install a
1936 "firstboot" script in Windows guests. It is required if you
1937 intend to use the --firstboot or --firstboot-command options
1938 with Windows guests.
1939 See also: "https://github.com/rwmjones/rhsrvany"
1941 pvvxsvc.exe
1943 This is a Windows binary shipped with SUSE VMDP, used to
1944 install a "firstboot" script in Windows guests. It is required
1945 if you intend to use the --firstboot or --firstboot-command
1946 options with Windows guests.
1947 "XDG_CACHE_HOME"
1949 Used to determine the location of the template cache. See
1950 "CACHING".
1951 "XDG_CONFIG_HOME"
1953 Used to determine the location of the user' sources. See "SOURCES
1954 OF TEMPLATES".
1955 "VIRT_BUILDER_DIRS"
1957 Used to determine the location of the system sources. See "SOURCES
1958 OF TEMPLATES".
1959
1961 This program returns 0 if successful, or non-zero if there was an
1962 error.
1963
1965 guestfs(3), guestfish(1), guestmount(1), virt-builder-repository(1),
1966 virt-copy-out(1), virt-customize(1), virt-get-kernel(1),
1967 virt-install(1), virt-rescue(1), virt-resize(1), virt-sysprep(1),
1968 oz-install(1), gpg(1), gpg2(1), curl(1), virt-make-fs(1),
1969 genisoimage(1), http://libguestfs.org/.
1970
1972 Richard W.M. Jones http://people.redhat.com/~rjones/
1973
1975 Copyright (C) 2013 Red Hat Inc.
1976
1978 This program is free software; you can redistribute it and/or modify it
1979 under the terms of the GNU General Public License as published by the
1980 Free Software Foundation; either version 2 of the License, or (at your
1981 option) any later version.
1982 This program is distributed in the hope that it will be useful, but
1984 WITHOUT ANY WARRANTY; without even the implied warranty of
1985 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
1986 General Public License for more details.
1987 You should have received a copy of the GNU General Public License along
1989 with this program; if not, write to the Free Software Foundation, Inc.,
1990 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
1991
1993 To get a list of bugs against libguestfs, use this link:
1994 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
1995 To report a new bug against libguestfs, use this link:
1997 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
1998 When reporting a bug, please supply:
2000 • The version of libguestfs.
2002 • Where you got libguestfs (eg. which Linux distro, compiled from
2004 source, etc)
2005 • Describe the bug accurately and give a way to reproduce it.
2007 • Run libguestfs-test-tool(1) and paste the complete, unedited output
2009 into the bug report.
2010guestfs-tools-1.46.1 2021-05-13 virt-builder(1)