1virt-dib(1) Virtualization Support virt-dib(1)
2
6 virt-dib - Run diskimage-builder elements
7
9 virt-dib -B DIB-LIB [options] elements...
10
12 Virt-dib is a tool for using the elements of "diskimage-builder" to
13 build a new disk image, generate new ramdisks, etc.
14 Virt-dib is intended as safe replacement for "diskimage-builder" and
16 its "ramdisk-image-create" mode, see "COMPARISON WITH DISKIMAGE-
17 BUILDER" for a quick comparison with usage of "diskimage-builder".
18 "diskimage-builder" is part of the TripleO OpenStack project:
20 https://wiki.openstack.org/wiki/TripleO.
21
23 Build simple images of distributions
24 virt-dib \
25 -B /path/to/diskimage-builder/lib \
26 -p /path/to/diskimage-builder/elements \
27 --envvar DIB_RELEASE=jessie \
28 --name debian-jessie \
29 debian vm
30 This builds a Debian Jessie (8.x) disk image, suitable for running as
32 virtual machine, saved as debian-jessie.qcow2.
33 Build ramdisks
35 virt-dib \
36 -B /path/to/diskimage-builder/lib \
37 -p /path/to/diskimage-builder/elements \
38 --ramdisk \
39 --name ramdisk \
40 ubuntu deploy-ironic
41 This builds a ramdisk for the Ironic OpenStack component based on the
43 Ubuntu distribution.
44
46 --help
47 Display help.
48 -B PATH
50 Set the path to the library directory of "diskimage-builder". This
51 is usually the lib subdirectory in the sources and when installed,
52 and /usr/share/diskimage-builder/lib when installed in /usr.
53 This parameter is mandatory, as virt-dib needs to provide it for
55 the elements (as some of them might use scripts in it). Virt-dib
56 itself does not make use of the library directory.
57 --arch ARCHITECTURE
59 Use the specified architecture for the output image. The default
60 value is the same as the host running virt-dib.
61 Right now this option does nothing more than setting the "ARCH"
63 environment variable for the elements, and it’s up to them to
64 produce an image for the requested architecture.
65 --checksum
67 Generate checksum files for the generated image. The supported
68 checksums are MD5, and SHA256.
69 --colors
71 --colours
72 Use ANSI colour sequences to colourize messages. This is the
73 default when the output is a tty. If the output of the program is
74 redirected to a file, ANSI colour sequences are disabled unless you
75 use this option.
76 --debug LEVEL
78 Set the debug level to "LEVEL", which is a non-negative integer
79 number. The default is 0.
80 This debug level is different than what -x and -v set, and it
82 increases the debugging information printed out. Specifically,
83 this sets the "DIB_DEBUG_TRACE", and any value > 0 enables tracing
84 in the scripts executed.
85 --docker-target TARGET
87 Set the repository and tag for docker.
88 This is used only when the formats include "docker", and it is
90 required in that case.
91 --drive DISK
93 Add the specified disk to be used as helper drive where to cache
94 files of the elements, like disk images, distribution packages,
95 etc.
96 See "HELPER DRIVE".
98 --drive-format raw
100 --drive-format qcow2
101 Specify the format of the helper drive. If this flag is not given
102 then it is auto-detected from the drive itself.
103 If working with untrusted raw-format guest disk images, you should
105 ensure the format is always specified.
106 This option is used only if --drive is specified.
108 See "HELPER DRIVE".
110 -p PATH
112 --element-path PATH
113 Add a new path with elements. Paths are used in the same order as
114 the -p parameters appear, so a path specified first is looked
115 first, and so on.
116 Obviously, it is recommended to add the path to the own elements of
118 "diskimage-builder", as most of the other elements will rely on
119 them.
120 --extra-packages PACKAGE,...
122 Install additional packages in the image being built.
123 This relies on the "install-packages" binary provided by the
125 package management elements.
126 This option can be specified multiple times, each time with
128 multiple packages separated by comma.
129 --envvar VARIABLE
131 --envvar VARIABLE=VALUE
132 Carry or set an environment variable for the elements.
133 See "ENVIRONMENT VARIABLES" below for more information on the
135 interaction and usage of environment variables.
136 This option can be used in two ways:
138 --envvar VARIABLE
140 Carry the environment variable "VARIABLE". If it is not set,
141 nothing is exported to the elements.
142 --envvar VARIABLE=VALUE
144 Set the environment variable "VARIABLE" with value "VALUE" for
145 the elements, regardless whether an environment variable with
146 the same name exists.
147 This can be useful to pass environment variable without
149 exporting them in the environment where virt-dib runs.
150 --exclude-element ELEMENT
152 Ignore the specified element.
153 --exclude-script SCRIPT
155 Ignore any element script named "SCRIPT", whichever element it is
156 in.
157 This can be useful in case some script does not run well with virt-
159 dib, for example when they really need "diskimage-builder"'s
160 environment.
161 --formats FORMAT,...
163 Set the list of output formats, separating them with comma.
164 Supported formats are:
166 "docker"
168 Import the image to docker, running docker import. The target
169 for the image must be specified using --docker-target.
170 Please note this operation usually requires the docker service
172 to be enabled, otherwise it will fail. Furthermore, docker is
173 run using sudo(8), so make sure the user has the permissions to
174 run at least docker.
175 "qcow2" (enabled by default)
177 QEMU’s qcow2. This output format requires the "qemu-img" tool.
178 "raw"
180 Raw disk format.
181 "squashfs"
183 An squashfs filesystem, compressed with XZ. This output format
184 requires the "squashfs" feature; see also "AVAILABILITY" in
185 guestfs(3).
186 "tar"
188 An uncompressed tarball.
189 "tgz"
191 A tarball compressed with gzip.
192 "vhd"
194 "Virtual Hard Disk" disk image. This output format requires
195 the "vhd-util" tool.
196 Please note that the version of "vhd-util" tool needs to be
198 patched to support the "convert" subcommand, and to be
199 bootable. The patch is available here:
200 https://github.com/emonty/vhd-util/blob/master/debian/patches/citrix.
201 --fs-type FILESYSTEM
203 Set the filesystem type to use for the root filesystem. The
204 default is "ext4".
205 See also "guestfs_filesystem_available" in guestfs(3).
207 --image-cache DIRECTORY
209 Set the path in the host where cache the resources used by the
210 elements of the "extra-data.d" phase. The default is
211 ~/.cache/image-create.
212 Please note that most of the resources fetched in phases other than
214 "extra-data.d" will be cached in the helper drive specified with
215 --drive; see also "HELPER DRIVE".
216 --install-type TYPE
218 Specify the default installation type. Defaults to "source".
219 Set to "package" to use package based installations by default.
221 --machine-readable
223 This option is used to make the output more machine friendly when
224 being parsed by other programs. See "MACHINE READABLE OUTPUT"
225 below.
226 -m MB
228 --memsize MB
229 Change the amount of memory allocated to the appliance. Increase
230 this if you find that the virt-dib execution runs out of memory.
231 The default can be found with this command:
233 guestfish get-memsize
235 --mkfs-options "OPTION STRING"
237 Add the specified options to mkfs(1), to be able to fine-tune the
238 root filesystem creation; the options are passed to the driver of
239 mfks(1), and not to mfks(1) itself. Note that --fs-type is used to
240 change the filesystem type.
241 You should use --mkfs-options at most once. To pass multiple
243 options, separate them with space, eg:
244 virt-dib ... --mkfs-options '-O someopt -I foo'
246 --network
248 --no-network
249 Enable or disable network access from the guest during the
250 installation.
251 Enabled is the default. Use --no-network to disable access.
253 The network only allows outgoing connections and has other minor
255 limitations. See "NETWORK" in virt-rescue(1).
256 This does not affect whether the guest can access the network once
258 it has been booted, because that is controlled by your hypervisor
259 or cloud environment and has nothing to do with virt-dib.
260 If you use --no-network, then the environment variable
262 "DIB_OFFLINE" is set to 1, signaling the elements that they should
263 use only cached resources when available. Note also that, unlike
264 with "diskimage-builder" where elements may still be able to access
265 to the network even with "DIB_OFFLINE=", under virt-dib network
266 will not be accessible at all.
267 --name NAME
269 Set the name of the output image file. The default is "image".
270 According to the chosen name, there will be the following in the
272 current directory:
273 $NAME.ext
275 For each output format, a file named after the output image
276 with the extension depending on the format; for example:
277 $NAME.qcow2, $NAME.raw, etc.
278 Not applicable in ramdisk mode, see "RAMDISK BUILDING".
280 $NAME.d
282 A directory containing any files created by the elements, for
283 example dib-manifests directory (created by the "manifests"
284 element), ramdisks and kernels in ramdisk mode, and so on.
285 $NAME.ext.checksum
287 When --checksum is specified, there will be files for each
288 supported checksum type; for example: $NAME.ext.md5,
289 $NAME.ext.sha256, etc.
290 Not applicable in ramdisk mode, see "RAMDISK BUILDING".
292 --no-delete-on-failure
294 Don’t delete the output files on failure to build. You can use
295 this to debug failures to run scripts.
296 The default is to delete the output files if virt-dib fails (or,
298 for example, some script that it runs fails).
299 --python PYTHON
301 Specify a different Python interpreter to use. Parts of
302 "diskimage-builder" are implemented in Python, and thus an
303 interpreter is needed.
304 "PYTHON" can either be an executable filename (e.g. python2, which
306 is then searched in $PATH), or a full path (e.g.
307 /usr/bin/python2). If not specified, the default value is python.
308 -q
310 --quiet
311 Don’t print ordinary progress messages.
312 --qemu-img-options option[,option,...]
314 Pass --qemu-img-options option(s) to the qemu-img(1) command to
315 fine-tune the output format. Options available depend on the
316 output format (see --formats) and the installed version of the
317 qemu-img program.
318 You should use --qemu-img-options at most once. To pass multiple
320 options, separate them with commas, eg:
321 virt-dib ... --qemu-img-options cluster_size=512,preallocation=metadata ...
323 --ramdisk
325 Set the ramdisk building mode.
326 See "RAMDISK BUILDING".
328 --ramdisk-element NAME
330 Set the name for the additional element added in ramdisk building
331 mode. The default is "ramdisk".
332 See "RAMDISK BUILDING".
334 --root-label LABEL
336 Set the label for the root filesystem in the created image.
337 Please note that some filesystems have different restrictions on
339 the length of their labels; for example, on "ext2/3/4" filesystems
340 labels cannot be longer than 16 characters, while on "xfs" they
341 have at most 12 characters.
342 The default depends on the actual filesystem for the root partition
344 (see --fs-type): on "xfs" is "img-rootfs", while "cloudimg-rootfs"
345 on any other filesystem.
346 --size SIZE
348 Select the size of the output disk, where the size can be specified
349 using common names such as "32G" (32 gigabytes) etc. The default
350 size is "5G".
351 To specify size in bytes, the number must be followed by the
353 lowercase letter b, eg: "--size 10737418240b".
354 See also virt-resize(1) for resizing partitions of an existing disk
356 image.
357 --skip-base
359 Skip the inclusion of the "base" element.
360 --smp N
362 Enable N ≥ 2 virtual CPUs for scripts to use.
363 -u Do not compress resulting qcow2 images. The default is to compress
365 them.
366 -v
368 --verbose
369 Enable debugging messages.
370 -V
372 --version
373 Display version number and exit.
374 -x Enable tracing of libguestfs API calls.
376
378 Unlike with "diskimage-builder", the environment of the host is not
379 inherited in the appliance when running most of the elements (i.e. all
380 except the ones in the "extra-data.d" phase).
381 To set environment for the elements being run, it is necessary to tell
383 virt-dib to use them, with the option --envvar. Such option allows to
384 selectively export environment variables when running the elements, and
385 it is the preferred way to pass environment variables to the elements.
386 To recap: if you want the environment variable "MYVAR" (and its
388 content) to be available to the elements, you can do either
389 export MYVAR # whichever is its value
391 virt-dib ... --envvar MYVAR ...
392 or
394 virt-dib ... --envvar MYVAR=value_of_it ...
396
398 Virt-dib runs most of the element in its own appliance, and thus not on
399 the host. Because of this, there is no possibility for elements to
400 cache resources directly on the host.
401 To solve this issue, virt-dib allows the usage of an helper drive where
403 to store cached resources, like disk images, distribution packages,
404 etc. While this means that there is a smaller space available for
405 caching, at least it allows to limit the space on the host for caches,
406 without assuming that elements will do that by themselves.
407 Currently this disk is either required to have a single partition on
409 it, or the first partition on it will be used. A disk with the latter
410 configuration can be easily created with guestfish(1) like the
411 following:
412 guestfish -N filename.img=fs:ext4:10G exit
414 The above will create a disk image called filename.img, 10G big, with a
416 single partition of type ext4; see "PREPARED DISK IMAGES" in
417 guestfish(1).
418 It is recommended for it to be ≥ 10G or even more, as elements will
420 cache disk images, distribution packages, etc. As with any disk image,
421 the helper disk can be easily resized using virt-resize(1) if more
422 space in it is needed.
423 The drive can be accessed like any other disk image, for example using
425 other tools of libguestfs such as guestfish(1):
426 guestfish -a filename.img -m /dev/sda1
428 If no helper drive is specified with --drive, all the resources cached
430 during a virt-dib run will be discarded.
431 RESOURCES INSIDE THE DRIVE
433 Inside the helper drive, it is possible to find the following
434 resources:
435 /home
437 This directory is set as "HOME" environment variable during the
438 build. It contains mostly the image cache (saved as
439 /home/.cache/image-create), and whichever other resource is cached
440 in the home directory of the user running the various tools.
441 /virt-dib-*.log
443 These are the logs of the elements being run within the libguestfs
444 appliance, which means all the phases except "extra-data.d".
445
447 Virt-dib can emulate also "ramdisk-image-create", which is a secondary
448 operation mode of "diskimage-builder". Instead of being a different
449 tool name, virt-dib provides easy access to this mode using the
450 --ramdisk switch.
451 In this mode:
453 · there is an additional ramdisk element added (see
455 --ramdisk-element)
456 · no image is produced (so --formats is ignored)
458 · $NAME.d (see --name) will contain initrd, kernel, etc
460
462 Virt-dib uses the standard temporary directory used by libguestfs, see
463 "ENVIRONMENT VARIABLES" in guestfs(3).
464 By default this location is /tmp (default value for "TMPDIR"), which on
466 some systems may be on a tmpfs filesystem, and thus defaulting to a
467 maximum size of half of physical RAM. If virt-dib exceeds this, it may
468 hang or exit early with an error. The solution is to point "TMPDIR" to
469 a permanent location used as temporary location, for example:
470 mkdir local-tmp
472 env TMPDIR=$PWD/local-tmp virt-dib ...
473 rm -rf local-tmp
474
476 Because of virt-dib runs most of the elements in its own appliance, all
477 the tools and libraries used by elements running outside the guest
478 (typically "root.d", "block-device.d", and "cleanup.d") need to be
479 present in the appliance as well. In case they are not, scripts will
480 fail typically with a "command not found" error.
481 For tools and libraries packaged by the distribution, the easy solution
483 is to tell libguestfs to include additional packages in the appliance.
484 This is doable by e.g. creating a new file with the additional
485 packages:
486 # echo wget > /usr/lib64/guestfs/supermin.d/dib-my-extra
488 The actual path to the supermin.d directory depends on the
490 distribution; additional files can list more packages, each in its own
491 line. For more details, see supermin(1).
492
494 Virt-dib is intended as safe replacement for "diskimage-builder" and
495 its "ramdisk-image-create" mode; the user-notable differences consist
496 in:
497 · the command line arguments; some of the arguments are the same as
499 available in "diskimage-builder", while some have different names:
500 disk-image-create virt-dib
502 ----------------- --------
503 -a ARCH --arch ARCH
504 --image-size SIZE --size SIZE
505 --max-online-resize SIZE doable using --mkfs-options
506 -n --skip-base
507 -o IMAGENAME --name IMAGENAME
508 -p PACKAGE(S) --extra-packages PACKAGE(S)
509 -t FORMAT(S) --formats FORMAT(S)
510 -x --debug 1
511 -x -x --debug 2
512 -x -x [-x ...] --debug 3/4/etc
513 · the location of non-image output files (like ramdisks and kernels)
515 · the way some of the cached resources are saved: using an helper
517 drive, not directly on the disk where virt-dib is run
518 · the need to specify a target size for the output disk, as opposed
520 to "diskimage-builder" calculating an optimal one
521 · the handling of environment variables, see "ENVIRONMENT VARIABLES".
523 Furthermore, other than the libguestfs own environment variables
525 (see "ENVIRONMENT VARIABLES" in guestfs(3)), virt-dib does not read
526 any other environment variable: this means that all the options and
527 behaviour changes are specified solely using command line arguments
528 · extra tools needed on some out-of-chroot phases need to be
530 available in the appliance, see "EXTRA DEPENDENCIES".
531 Elements themselves should notice no difference in they way they are
533 run; behaviour differences may due to wrong assumptions in elements, or
534 not correct virt-dib emulation.
535 Known issues at the moment:
537 · (none)
539
541 The --machine-readable option can be used to make the output more
542 machine friendly, which is useful when calling virt-dib from other
543 programs, GUIs etc.
544 Use the option on its own to query the capabilities of the virt-dib
546 binary. Typical output looks like this:
547 $ virt-dib --machine-readable
549 virt-dib
550 output:qcow2
551 output:tar
552 output:raw
553 output:vhd
554 A list of features is printed, one per line, and the program exits with
556 status 0.
557 The "output:" features refer to the output formats (--formats command
559 line option) supported by this binary.
560
562 Virt-dib has been tested with "diskimage-builder" (and its elements) ≥
563 0.1.43; from time to time also with "tripleo-image-elements" and
564 "sahara-image-elements".
565 Previous versions may work, but it is not guaranteed.
567
569 This program returns 0 if successful, or non-zero if there was an
570 error.
571
573 guestfs(3), guestfish(1), virt-resize(1), http://libguestfs.org/.
574
576 Pino Toscano ("ptoscano at redhat dot com")
577
579 Copyright (C) 2015 Red Hat Inc.
580
582 This program is free software; you can redistribute it and/or modify it
583 under the terms of the GNU General Public License as published by the
584 Free Software Foundation; either version 2 of the License, or (at your
585 option) any later version.
586 This program is distributed in the hope that it will be useful, but
588 WITHOUT ANY WARRANTY; without even the implied warranty of
589 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
590 General Public License for more details.
591 You should have received a copy of the GNU General Public License along
593 with this program; if not, write to the Free Software Foundation, Inc.,
594 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
595
597 To get a list of bugs against libguestfs, use this link:
598 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
599 To report a new bug against libguestfs, use this link:
601 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
602 When reporting a bug, please supply:
604 · The version of libguestfs.
606 · Where you got libguestfs (eg. which Linux distro, compiled from
608 source, etc)
609 · Describe the bug accurately and give a way to reproduce it.
611 · Run libguestfs-test-tool(1) and paste the complete, unedited output
613 into the bug report.
614libguestfs-1.38.2 2018-05-15 virt-dib(1)