file system and finally, if the user selects *Reset*, the system will ignore
all changes made so far and will start the image creation process again.
-Usage example
-=============
-
-Supposing you have snf-image-creator installed on a machine (hereafter referred
-to as your **host machine**), you can follow the next steps to upload and
-register an image of an OS of your preference (hereafter referred to as your
-**guest OS**) to your synnefo deployment.
-
- * `Step 1: Install the guest OS`_
- * `Step 2: Create and upload an image of the guest OS`_
- * `Step 3: Create your VM`_
-
-
-Step 1: Install the guest OS
------------------------------
-
-The guest OS has to be installed on a media such as a block device or a regular
-raw file, that can be **accessible** by your host machine.
-
-But why is accessible empasized? Well, because you don't need to do the
-installation of the guest OS on your host machine. You can just as well install
-it on a raw file, upload it on Pithos+, download it on your host machine and
-use it for Step 2.
-
-*Note: If you have a guest OS already installed, you may want to skip the
-next step. However, be sure to check out the* `Caveats`_ *section, where
-some requirements about the guest OS are presented.*
-
-Installation example
-""""""""""""""""""""
-
-To simplify things a bit, we will install the guest OS on the host machine
-where snf-image-creator is installed. We will assume that the host machine is
-an Ubuntu 12.04 ~okeanos VM, built with max specifications (4 CPUs, 2GB of
-ram, 40GB of disk space at the time of writing this).
-
-*Note: Since the installation of the guest OS will take place on your host
-VM, you must be able to connect to it graphically. This is covered by our*
-`connection guide <https://okeanos.grnet.gr/support/user-guide/cyclades-how-do-
-i-connect-to-a-vm/#windows-linux-host-to-linux-guest-graphical>`_.
+Creating a new image
+====================
-For our guest OS, we will choose, Linux Mint, which is the most hyped Linux
-OS according to Distrowatch. A new version has just been released, so
-this seems like a fine choice. ::
+Suppose you want to create a new Ubuntu server image. Download the installation
+disk from the Internet:
- Warning: The installation might take a long time (~1 hour) and a bit of
- lagginess due to nested virtualization is to be expected.
+.. code-block:: console
-Fire up your terminal, go to your home directory and type the following to
-download the Linux Mint live cd::
+ $ wget http://ubuntureleases.tsl.gr/12.04.1/ubuntu-12.04.1-server-amd64.iso
- $ wget http://ftp.ntua.gr/pub/linux/linuxmint//stable/14/linuxmint-14-mate-dvd-64 bit.iso
+Verify that it has been downloaded correctly:
-Verify that it has been downloaded correctly. If the following command
-prints "OK". then you are good to go::
+.. code-block:: console
- $ echo 'b370ac59d1ac6362f1662cfcc22a489c linuxmint-14-mate-dvd-64bit.iso' > check.md5
+ $ echo 'a8c667e871f48f3a662f3fbf1c3ddb17 ubuntu-12.04.1-server-amd64.iso' > check.md5
$ md5sum -c check.md5
-Allocate a few gigs of space to create a sparse file::
-
- $ truncate -s 7G linuxmint.raw
+Create a 2G sparce file to host the new system:
-Use `kvm` to boot the Live CD::
-
- $ sudo kvm -m 1200 -smp 4 -boot d -drive \
- file=linuxmint.raw,format=raw,cache=none,if=virtio \
- -cdrom linuxmint-14-mate-dvd-64bit.iso
+.. code-block:: console
- At a glance, let's see what the above options do:
- -m 1200: Use 1200MB of RAM for the guest OS. You should
- allocate as much as possible
- -smp 4: Simulate an SMP system with 4 CPUs for the
- guest OS to use.
- -boot d: Place cdrom first in the boot order
- file=opensuse.raw Use this raw file as the "hard disk" for the
- installation
- if=virtio: Inform the OS that it should preload the
- VirtIO drivers (more on that on `Caveats`_
- section)
- -cdrom linuxmint-14-mate-dvd-64bit.iso:
- "Insert" Linux Mint's live cd in the cdrom
- drive
+ $ truncate -s 2G ubuntu_hd.raw
-Wait a few seconds and then a new screen with the Linux Mint logo should
-appear. You don't have to press any key since it will boot automatically to
-Linux Mint's live desktop after a few minutes.
+And install the Ubuntu system on this file:
-|qemu-live|
+.. code-block:: console
-Choose "Install Linux Mint". The installation process should be pretty
-straightforward. Just keep two things in mind:
+ $ sudo kvm -boot d -drive file=ubuntu_hd.raw,format=raw,cache=none,if=virtio \
+ -m 1000 -cdrom ubuntu-12.04.1-server-amd64.iso
-* The username you choose will also be used later on, when you create a VM
- from this OS image. The password, however, will be removed and you will
- be given a new one.
-* The installed OS must have no more than one primary partition and
- optionally a swap partition. You can read more in the `Caveats`_
- section below. You don't have to worry about it in this installation
- however, since the default option takes care of that.
+.. note::
- |qemu-partition|
+ During the installation, you will be asked about the partition scheme. Since
+ snf-image-creator does not support LVM partitions, you are advised to create
+ regular partitions.
-After the installation is complete, you can close the QEMU window. You
+When the installation is complete, you can close the QEMU window. You
will be able to boot your installed OS and make any changes you want to it
-using the following command::
-
- $ sudo kvm -m 1200 -smp 4 -boot d -drive \
- file=linuxmint.raw,format=raw,cache=none,if=virtio
-
-At the very least, you should install OpenSSH server to connect to your VM
-properly. You can install OpenSSH server using the following command::
-
- $ sudo apt-get install openssh-server
-
-Bear in mind that once the OS image has been uploaded to your synnefo
-deployment, you will not be able to make changes to it. Since you can only
-apply changes to your raw file, you are advised to do so now and then proceed
-to Step 2.
-
-Caveats
-"""""""
-This is a list of restrictions you must have in mind while installing the
-guest OS:
-
-**Partitions**
-
-The installation must consist of no more than one primary partition. It
-can have a swap partition though, which should ideally - but not
-necessarily - be located at the end of the media. In this case, the
-uploaded image will be much smaller and the VM deployment process much
-faster.
-
-**VirtIO drivers**
-
-Depending on your synnefo-deployment, you may need to use para-virtualized
-drivers for your storage and network needs.
-
-~okeanos uses the VirtIO framework which is essential for the ~okeanos VMs
-to work properly since their disk I/O controller and Ethernet cards are
-para-virtualized.
-
-Fortunately, you will not need to deal with the installation of VirtIO drivers
-directly, since they are included in Linux kernel since version 2.6.25 and
-shipped with all the modern Linux distributions. However, if the VirtIO drivers
-are built as a module (and most modern OSes do so), they need to be preloaded
-using an initial ramdisk (initramfs), otherwise the VM you create from this OS
-image will not be able to boot.
-
-Debian derivatives will create an initial ramdisk with VirtIO included if
-they are connected during the installation on a para-virtualized interface
-(the "if=virtio" option in the Linux Mint example).
-
-In many other distros though, this is not the case. In Arch Linux for
-example, the user needs to manually add virtio_blk and virtio_pci drivers
-in /etc/mkinitcpio.conf and rebuild the initial ramdisk to make the
-virtio drivers get preloaded during boot. You can read more in the `Arch
-Linux wiki <https://wiki.archlinux.org/index.php/KVM#Paravirtualized_
-guests_.28virtio.29>`_ on how to do it.
-
-For now, snf-image-creator cannot resolve this kind of problems and it's
-left to the user to do it.
-
-Step 2: Create and upload an image of the guest OS
---------------------------------------------------
+(e.g. install openssh-server) using the following command::
-This is the step on which we use snf-image-creator. There are actually two
-variants of snf-image-creator, `snf-image-creator`_ and `snf-mkimage`_, both
-achieving the same results but suited for different needs. Their scope is
-documented at the start of the `Usage`_ section of this document.
+ $ sudo kvm -m 1000 -drive file=linuxmint.raw,format=raw,cache=none,if=virtio
-*Note: Both tools take a snapshot of the installed OS on the media
-provided to them. So, any changes they apply do not affect the OS
-installed on the original media.*
+After you're done, become root, activate the virtual environment you have
+installed snf-image-creator in, and use *snf-mkimage* to create and upload the
+image:
-Let's see both tools in action. We will use them to create an image of the
-Linux Mint 14 OS we installed in Step 2.
-
-snf-mkimage
-"""""""""""
-
-In order to use snf-mkimage, simply type::
-
- $ sudo snf-mkimage linuxmint.raw
-
-snf-mkimage will initially check if the media is indeed a single disk
-partition or a raw file representing a hard disk. Then, it will use
-heuristics to understand which OS has been installed on the media. After
-that, you will be asked which mode you prefer.
-
-|mkimage-wizard|
-
-* Wizard mode is intuitive and consists of 4 simple steps.
-* Expert mode has an abundance of options but requires a bit of knowledge
- of the inner workings of Cyclades from your part. You can learn more on the
- `Expert Mode`_ section of snf-mkimage.
-
-For our tutorial, we will use Wizard mode. So, choose "Wizard" and then provide
-a name for the image.
-
-|mkimage1|
-
-This name will appear on Pithos+ and on the Public Images section of Cyclades.
-
-Then, provide a description for the image.
-
-|mkimage2|
-
-This will appear under the chosen image name on the Public Images section of
-cyclades.
-
-Next, add your account e-mail
-
-|mkimage3|
-
-... your account token...
-
-|mkimage4|
-
-...and you're done! A list operations will appear on your console.
-
-|mkimage-results|
-
-We will briefly comment on the above output.
-
-* **Sysprep:** Operations from 1/9 to 9/9 are part of the system
- preparation operations and are best explained in the snf-image-creator's
- `sysprep`_ section.
-* **Shrinking:** When shrinking the image, we check if a swap partition
- exists at the end of the media. If this is the case, it will be removed
- and re-inserted upon the deployment process of the VM. Alternatively, if
- the swap partition lies at the start of the media, it will be left
- untouched. On both cases, the primary partition will be shrunken as much
- as possible. On this example, we can see that the final size is 3.5GB,
- whereas the orginal size was 7GB. This means that the image was reduced
- by half, a pretty impressive feat.
-* **MD5SUM:** The md5sum of the image is used later on to verify that the
- image has been uploaded successfully.
-* **Uploading:** Everytime you upload an OS image, every block is hashed,
- checked against existing blocks in Pithos+ and finally uploaded, if no
- other block has the same hash.
-
- *Consider this example: You have just uploaded a Gentoo Linux image but
- had forgotten to install a necessary package. In this case, you would
- probably edit the OS in the raw file and then use snf-mkimage to upload
- the new image. However, since there is an almost identical image already
- uploaded on Pithos+, you can just as well upload only the blocks that
- differentiate those two images. This is both time and space efficient.*
-
-Finally, after the image has been uploaded successfully, you will be asked
-whether you want to save a local copy of the **shrunken** image. This is
-just a copy of the diskdump that has been uploaded to Pithos+ and, in case
-you are confused, the original OS installed on the media (linuxmint.raw in
-our example) remains intact.
-
-snf-image-creator
-"""""""""""""""""
-
-snf-image-creator is the command-line equivalent of snf-mkimage. All the
-info provided in the steps above are given now as options, which makes it
-ideal for scripting purposes. The full set of options can be found in the
-`Usage section <#non-interactive-version>`_ of snf-image-creator's
-documentation.
-
-This tool is most commonly used with the following set of options::
-
- $ sudo snf-image-creator linuxmint.raw -a user@email.com \
- -t hUudl4DEIlomlnvWnv7Rlw== -u linuxmint.diskdump -r "Linux Mint 14 Nadia"
-
-As you can see, these options are exactly what snf-mkimage's steps
-translate to. You can also see that the output is nearly identical:
-
-|image-creator|
-
-Step 3: Create your VM
-----------------------
-
-Creating a VM out of an uploaded custom image is a fairly simple task.
-Just select "New Machine", go to "My Images" section and select your
-image.
+.. code-block:: console
-|custom-vm|
+ $ sudo -s
+ $ source /path/to/snf-image-env/bin/activate
+ $ snf-mkimage ubuntu_hd.raw
-Alternatively, if you want to create a VM from another user's custom
-image, you can go to the "Public Images" section.
+In the first screen you will be asked to choose if you want to run the program
+in *Wizard* or *Expert* mode. Choose *Wizard*.
-.. |qemu-live| image:: /snapshots/qemu-live.png
+.. image:: /snapshots/01_wizard.png
-.. |qemu-partition| image:: /snapshots/qemu-partition.png
+Then you will be asked to provide a name, a description, an *~okeanos* account
+and the token corresponding to this account. After that you will be asked to
+confirm the provided data.
-.. |mkimage-wizard| image:: /snapshots/mkimage-wizard.png
+.. image:: /snapshots/06_confirm.png
-.. |mkimage1| image:: /snapshots/mkimage1.png
+Choosing *YES* will create the image and upload it to your *~okeanos* account.
-.. |mkimage2| image:: /snapshots/mkimage2.png
+Some caveats on image creation
+==============================
-.. |mkimage3| image:: /snapshots/mkimage3.png
+Para-virtualized drivers
+------------------------
-.. |mkimage4| image:: /snapshots/mkimage4.png
+*~Okeanos* uses the *VirtIO* framework. The disk I/O controller and the
+Ethernet cards on the VM instances are para-virtualized and need special
+*VirtIO* drivers. Those drivers are included in the Linux Kernel mainline since
+version 2.6.25 and are shipped with all the popular Linux distributions. The
+problem is that if the driver for the para-virtualized disk I/O controller is
+built as module, it needs to be preloaded using an initial ramdisk, otherwise
+the VM will not be able to boot.
-.. |mkimage-fin| image:: /snapshots/mkimage-fin.png
+In the image creation demonstration above, we initially installed the Ubuntu
+system on a hard disk (*ubuntu_hd.raw*) that was connected on a
+para-virtualized interface (pay attention to the *if=virtio* option of the kvm
+line). Ubuntu and Debian create a generic initial ramdisk file that contains
+many different modules, including the VirtIO drivers. In many distros this is
+not the case. In Arch Linux for example, the user needs to manually add
+*virtio_blk* and *virtio_pci* drivers in */etc/mkinitcpio.conf* and rebuild the
+initial ramdisk [#f1]_ to make the virtio drivers get preloaded during boot.
+For now, *snf-image-creator* cannot resolve this kind of problems and it's left
+to the user to do it.
-.. |mkimage-results| image:: /snapshots/mkimage-results.png
+Swap partitions
+---------------
-.. |image-creator| image:: /snapshots/image-creator.png
+If you want your image to have a swap partitions, make sure this is the last
+partition on the disk. If snf-image-creator detects a swap partition in the end
+of the input media, it will remove the partition when shrinking and will save
+enough information to be able to recreate it during image deployment. This will
+make the image smaller and will speed up the deployment process.
-.. |custom-vm| image:: /snapshots/custom-vm.png
+.. rubric:: Footnotes
+.. [#f1] https://wiki.archlinux.org/index.php/KVM#Paravirtualized_guests_.28virtio.29
projects / snf-image-creator / commitdiff