4 snf-image-creator comes in 2 variants:
5 * snf-image-creator: A non-interactive command line program
6 * snf-mkimage: A user-friendly dialog-based program
8 Non-interactive version
9 =======================
11 snf-image-creator receives the following options:
13 .. code-block:: console
15 $ snf-image-creator --help
17 Usage: snf-image-creator [options] <input_media>
20 --version show program's version number and exit
21 -h, --help show this help message and exit
22 -o FILE, --outfile=FILE
24 -f, --force overwrite output files if they exist
25 -s, --silent silent mode, only output errors
26 -u FILENAME, --upload=FILENAME
27 upload the image to pithos with name FILENAME
28 -r IMAGENAME, --register=IMAGENAME
29 register the image with ~okeanos as IMAGENAME
30 -a ACCOUNT, --account=ACCOUNT
31 Use this ACCOUNT when uploading/registering images
33 -m KEY=VALUE, --metadata=KEY=VALUE
34 Add custom KEY=VALUE metadata to the image
35 -t TOKEN, --token=TOKEN
36 Use this token when uploading/registering images
38 --print-sysprep print the enabled and disabled system preparation
39 operations for this input media
40 --enable-sysprep=SYSPREP
41 run SYSPREP operation on the input media
42 --disable-sysprep=SYSPREP
43 prevent SYSPREP operation from running on the input
45 --no-sysprep don't perform system preparation
46 --no-shrink don't shrink any partition
49 Most input options are self-describing. If you want to save a local copy for
50 the image you create, you specify *-o* option. To upload the image to
51 *pithos+*, you specify valid credentials with *-a* and *-t* options and a
52 filename using *-u*. If you want to register the image with *~okeanos*,
53 in addition to *-u* specify a registration name using *-r*.
55 By default snf-image-creator will perform a number of system preparation
56 operations on the snapshot of the media and will shrink the last partition
57 found, before extracting the image. Both can be disabled by specifying
58 *--no-sysprep* and *--no-shrink* respectively.
60 If *--print-sysprep* is defined, the program will exit after outputing a
61 list of enabled and disabled system preparation operation appliable to this
62 media source. The user can enable or disable specific *syspreps* when creating
63 an image, using *-{enable,disable}-sysprep* options. You can specify those
64 options multiple times to enable or disable multiple *syspreps*.
66 Running *snf-image-creator* with *--print-sysprep* on a raw file that hosts a
67 debian system, we get the following output:
71 .. code-block:: console
73 $ snf-image-creator --print-sysprep debian_desktop.img
77 Examining source media `debian_desktop.img'... looks like an image file
78 Snapshotting media source... done
79 Enabling recovery proc
80 Launching helper VM... done
81 Inspecting Operating System... found a(n) debian system
82 Mounting the media read-only... done
84 Enabled system preparation operations:
86 Remove all regular files under /var/cache
89 Empty all files under /var/log
92 Remove all passwords and lock all user accounts
95 Remove all files under /tmp and /var/tmp
98 Delete sensitive userdata
101 Replace acpid powerdown action scripts to immediately shutdown the
102 system without checking if a GUI is running.
104 remove-persistent-net-rules:
105 Remove udev rules that will keep network interface names persistent
106 after hardware changes and reboots. Those rules will be created again
107 the next time the image runs.
110 Remove swap entry from /etc/fstab. If swap is the last partition
111 then the partition will be removed when shrinking is performed. If the
112 swap partition is not the last partition in the disk or if you are not
113 going to shrink the image you should probably disable this.
115 use-persistent-block-device-names:
116 Scan fstab & grub configuration files and replace all non-persistent
117 device references with UUIDs.
119 Disabled system preparation operations:
121 Remove all files under /var/mail and /var/spool/mail
123 remove-user-accounts:
124 Remove all user accounts with id greater than 1000
129 If we want the image to have all normal user accounts and all mail files
130 removed, we can create it specifying *--enable-sysprep* option like this:
132 .. code-block:: console
134 $ snf-image-creator --enable-sysprep cleanup-mail --enable-sysprep remove-user-accounts ...
139 *snf-mkimage* receives the following options:
141 .. code-block:: console
143 $ Usage: snf-mkimage [options] [<input_media>]
146 --version show program's version number and exit
147 -h, --help show this help message and exit
148 -l FILE, --logfile=FILE
149 log all messages to FILE
151 If the input media is not specified in the command line, in the first dialog
152 box the user will be asked to specify it. After the input media is examined and
153 the program is initialized, the user will be given the choice to run
154 *snf-mkimage* in *wizard* or *expert* mode.
159 When *snf-mkimage* runs in *wizard* mode, the user is just asked to provide the
160 following basic information:
162 * Name: A short name for the image (ex. "Slackware")
163 * Description: An one-line description for the image (ex. "Slackware Linux 14.0 with KDE")
164 * Account: An *~okeanos* account email
165 * Token: A token corresponding to the account defined previously
167 After confirming, the image will be extracted, uploaded to *pithos+* and
168 registered to *~okeanos*. The user will also be given the choice to keep a local
169 copy of it. For most users the functionality this mode provides should be
175 Expert mode allows the user to have better control on the image creation
176 process. In the picture below the main menu can be seen:
178 .. image:: /snapshots/main_menu.png
180 In the *Customize* sub-menu the user can control:
182 * The system preparation operations that will be applied on the media
183 * Whether the image will be shrunk or not
184 * The properties associated with the image
185 * The configuration tasks that will run during image deployment
187 In the *Register* sub-menu the user can provide:
189 * The credentials to login to *~okeanos*
190 * A pithos filename for the uploaded *diskdump* image
191 * A name for the image to be registered to *~okeanos* with
193 By choosing the *Extract* menu entry the user can dump the image to the local
194 file system and finally, if the user selects *Reset*, the system will ignore
195 all changes made so far and will start the image creation process again.
200 Supposing you have snf-image-creator installed on a machine (hereafter referred
201 to as your **host machine**), you can follow the next steps to upload and
202 register an image of an OS of your preference (hereafter referred to as your
203 **guest OS**) to your synnefo deployment.
205 * `Step 1: Install the guest OS`_
206 * `Step 2: Create and upload an image of the guest OS`_
207 * `Step 3: Create your VM`_
210 Step 1: Install the guest OS
211 -----------------------------
213 The guest OS has to be installed on a media such as a block device or a regular
214 raw file, that can be **accessible** by your host machine.
216 But why is accessible empasized? Well, because you don't need to do the
217 installation of the guest OS on your host machine. You can just as well install
218 it on a raw file, upload it on Pithos+, download it on your host machine and
221 *Note: If you have a guest OS already installed, you may want to skip the
222 next step. However, be sure to check out the* `Caveats`_ *section, where
223 some requirements about the guest OS are presented.*
228 To simplify things a bit, we will install the guest OS on the host machine
229 where snf-image-creator is installed. We will assume that the host machine is
230 an Ubuntu 12.04 ~okeanos VM, built with max specifications (4 CPUs, 2GB of
231 ram, 40GB of disk space at the time of writing this).
233 *Note: Since the installation of the guest OS will take place on your host
234 VM, you must be able to connect to it graphically. This is covered by our*
235 `connection guide <https://okeanos.grnet.gr/support/user-guide/cyclades-how-do-
236 i-connect-to-a-vm/#windows-linux-host-to-linux-guest-graphical>`_.
238 For our guest OS, we will choose, Linux Mint, which is the most hyped Linux
239 OS according to Distrowatch. A new version has just been released, so
240 this seems like a fine choice. ::
242 Warning: The installation might take a long time (~1 hour) and a bit of
243 lagginess due to nested virtualization is to be expected.
245 Fire up your terminal, go to your home directory and type the following to
246 download the Linux Mint live cd::
248 $ wget http://ftp.ntua.gr/pub/linux/linuxmint//stable/14/linuxmint-14-mate-dvd-64 bit.iso
250 Verify that it has been downloaded correctly. If the following command
251 prints "OK". then you are good to go::
253 $ echo 'b370ac59d1ac6362f1662cfcc22a489c linuxmint-14-mate-dvd-64bit.iso' > check.md5
254 $ md5sum -c check.md5
256 Allocate a few gigs of space to create a sparse file::
258 $ truncate -s 7G linuxmint.raw
260 Use `kvm` to boot the Live CD::
262 $ sudo kvm -m 1200 -smp 4 -boot d -drive \
263 file=linuxmint.raw,format=raw,cache=none,if=virtio \
264 -cdrom linuxmint-14-mate-dvd-64bit.iso
266 At a glance, let's see what the above options do:
267 -m 1200: Use 1200MB of RAM for the guest OS. You should
268 allocate as much as possible
269 -smp 4: Simulate an SMP system with 4 CPUs for the
271 -boot d: Place cdrom first in the boot order
272 file=opensuse.raw Use this raw file as the "hard disk" for the
274 if=virtio: Inform the OS that it should preload the
275 VirtIO drivers (more on that on `Caveats`_
277 -cdrom linuxmint-14-mate-dvd-64bit.iso:
278 "Insert" Linux Mint's live cd in the cdrom
281 Wait a few seconds and then a new screen with the Linux Mint logo should
282 appear. You don't have to press any key since it will boot automatically to
283 Linux Mint's live desktop after a few minutes.
287 Choose "Install Linux Mint". The installation process should be pretty
288 straightforward. Just keep two things in mind:
290 * The username you choose will also be used later on, when you create a VM
291 from this OS image. The password, however, will be removed and you will
293 * The installed OS must have no more than one primary partition and
294 optionally a swap partition. You can read more in the `Caveats`_
295 section below. You don't have to worry about it in this installation
296 however, since the default option takes care of that.
300 After the installation is complete, you can close the QEMU window. You
301 will be able to boot your installed OS and make any changes you want to it
302 using the following command::
304 $ sudo kvm -m 1200 -smp 4 -boot d -drive \
305 file=linuxmint.raw,format=raw,cache=none,if=virtio
307 At the very least, you should install OpenSSH server to connect to your VM
308 properly. You can install OpenSSH server using the following command::
310 $ sudo apt-get install openssh-server
312 Bear in mind that once the OS image has been uploaded to your synnefo
313 deployment, you will not be able to make changes to it. Since you can only
314 apply changes to your raw file, you are advised to do so now and then proceed
319 This is a list of restrictions you must have in mind while installing the
324 The installation must consist of no more than one primary partition. It
325 can have a swap partition though, which should ideally - but not
326 necessarily - be located at the end of the media. In this case, the
327 uploaded image will be much smaller and the VM deployment process much
332 Depending on your synnefo-deployment, you may need to use para-virtualized
333 drivers for your storage and network needs.
335 ~okeanos uses the VirtIO framework which is essential for the ~okeanos VMs
336 to work properly since their disk I/O controller and Ethernet cards are
339 Fortunately, you will not need to deal with the installation of VirtIO drivers
340 directly, since they are included in Linux kernel since version 2.6.25 and
341 shipped with all the modern Linux distributions. However, if the VirtIO drivers
342 are built as a module (and most modern OSes do so), they need to be preloaded
343 using an initial ramdisk (initramfs), otherwise the VM you create from this OS
344 image will not be able to boot.
346 Debian derivatives will create an initial ramdisk with VirtIO included if
347 they are connected during the installation on a para-virtualized interface
348 (the "if=virtio" option in the Linux Mint example).
350 In many other distros though, this is not the case. In Arch Linux for
351 example, the user needs to manually add virtio_blk and virtio_pci drivers
352 in /etc/mkinitcpio.conf and rebuild the initial ramdisk to make the
353 virtio drivers get preloaded during boot. You can read more in the `Arch
354 Linux wiki <https://wiki.archlinux.org/index.php/KVM#Paravirtualized_
355 guests_.28virtio.29>`_ on how to do it.
357 For now, snf-image-creator cannot resolve this kind of problems and it's
358 left to the user to do it.
360 Step 2: Create and upload an image of the guest OS
361 --------------------------------------------------
363 This is the step on which we use snf-image-creator. There are actually two
364 variants of snf-image-creator, `snf-image-creator`_ and `snf-mkimage`_, both
365 achieving the same results but suited for different needs. Their scope is
366 documented at the start of the `Usage`_ section of this document.
368 *Note: Both tools take a snapshot of the installed OS on the media
369 provided to them. So, any changes they apply do not affect the OS
370 installed on the original media.*
372 Let's see both tools in action. We will use them to create an image of the
373 Linux Mint 14 OS we installed in Step 2.
378 In order to use snf-mkimage, simply type::
380 $ sudo snf-mkimage linuxmint.raw
382 snf-mkimage will initially check if the media is indeed a single disk
383 partition or a raw file representing a hard disk. Then, it will use
384 heuristics to understand which OS has been installed on the media. After
385 that, you will be asked which mode you prefer.
389 * Wizard mode is intuitive and consists of 4 simple steps.
390 * Expert mode has an abundance of options but requires a bit of knowledge
391 of the inner workings of Cyclades from your part. You can learn more on the
392 `Expert Mode`_ section of snf-mkimage.
394 For our tutorial, we will use Wizard mode. So, choose "Wizard" and then provide
395 a name for the image.
399 This name will appear on Pithos+ and on the Public Images section of Cyclades.
401 Then, provide a description for the image.
405 This will appear under the chosen image name on the Public Images section of
408 Next, add your account e-mail
412 ... your account token...
416 ...and you're done! A list operations will appear on your console.
420 We will briefly comment on the above output.
422 * **Sysprep:** Operations from 1/9 to 9/9 are part of the system
423 preparation operations and are best explained in the snf-image-creator's
425 * **Shrinking:** When shrinking the image, we check if a swap partition
426 exists at the end of the media. If this is the case, it will be removed
427 and re-inserted upon the deployment process of the VM. Alternatively, if
428 the swap partition lies at the start of the media, it will be left
429 untouched. On both cases, the primary partition will be shrunken as much
430 as possible. On this example, we can see that the final size is 3.5GB,
431 whereas the orginal size was 7GB. This means that the image was reduced
432 by half, a pretty impressive feat.
433 * **MD5SUM:** The md5sum of the image is used later on to verify that the
434 image has been uploaded successfully.
435 * **Uploading:** Everytime you upload an OS image, every block is hashed,
436 checked against existing blocks in Pithos+ and finally uploaded, if no
437 other block has the same hash.
439 *Consider this example: You have just uploaded a Gentoo Linux image but
440 had forgotten to install a necessary package. In this case, you would
441 probably edit the OS in the raw file and then use snf-mkimage to upload
442 the new image. However, since there is an almost identical image already
443 uploaded on Pithos+, you can just as well upload only the blocks that
444 differentiate those two images. This is both time and space efficient.*
446 Finally, after the image has been uploaded successfully, you will be asked
447 whether you want to save a local copy of the **shrunken** image. This is
448 just a copy of the diskdump that has been uploaded to Pithos+ and, in case
449 you are confused, the original OS installed on the media (linuxmint.raw in
450 our example) remains intact.
455 snf-image-creator is the command-line equivalent of snf-mkimage. All the
456 info provided in the steps above are given now as options, which makes it
457 ideal for scripting purposes. The full set of options can be found in the
458 `Usage section <#non-interactive-version>`_ of snf-image-creator's
461 This tool is most commonly used with the following set of options::
463 $ sudo snf-image-creator linuxmint.raw -a user@email.com \
464 -t hUudl4DEIlomlnvWnv7Rlw== -u linuxmint.diskdump -r "Linux Mint 14 Nadia"
466 As you can see, these options are exactly what snf-mkimage's steps
467 translate to. You can also see that the output is nearly identical:
471 Step 3: Create your VM
472 ----------------------
474 Creating a VM out of an uploaded custom image is a fairly simple task.
475 Just select "New Machine", go to "My Images" section and select your
480 Alternatively, if you want to create a VM from another user's custom
481 image, you can go to the "Public Images" section.
483 .. |qemu-live| image:: /snapshots/qemu-live.png
485 .. |qemu-partition| image:: /snapshots/qemu-partition.png
487 .. |mkimage-wizard| image:: /snapshots/mkimage-wizard.png
489 .. |mkimage1| image:: /snapshots/mkimage1.png
491 .. |mkimage2| image:: /snapshots/mkimage2.png
493 .. |mkimage3| image:: /snapshots/mkimage3.png
495 .. |mkimage4| image:: /snapshots/mkimage4.png
497 .. |mkimage-fin| image:: /snapshots/mkimage-fin.png
499 .. |mkimage-results| image:: /snapshots/mkimage-results.png
501 .. |image-creator| image:: /snapshots/image-creator.png
503 .. |custom-vm| image:: /snapshots/custom-vm.png