Usage
-=====
+^^^^^
snf-image-creator comes in 2 variants:
* snf-image-creator: A non-interactive command line program
* snf-mkimage: A user-friendly dialog-based program
Non-interactive version
------------------------
+=======================
snf-image-creator receives the following options:
Most input options are self-describing. If you want to save a local copy for
-the image, you need to specify *-o* option. In order to upload the image to
-pithos, you need to specify valid credentials with *-a* and *-t* options and a
-filename using *-u* option. To also register the image with ~okeanos, specify a
-name using the *-r* option.
-
-By default snf-image-creator will run a number of system preparation tasks on
-the snapshot of the media and will shrink the last partition found, before
-extracting the image. Both can be disabled by specifying *--no-sysprep* and
-*--no-shrink* respectively.
-
-If *--print-sysprep* is defined, then snf-image-creator will not create an
-image at all. It will only run the OS detection part and will output the system
-preparation tasks that would and would not run on the image. This behavior is,
-convenient because it allows you to see the available system preparation tasks
-that you can enable or disable with *-{enable,disable}-sysprep* options when
-you create a new image.
+the image you create, you specify *-o* option. To upload the image to
+*pithos+*, you specify valid credentials with *-a* and *-t* options and a
+filename using *-u*. If you want to register the image with *~okeanos*,
+in addition to *-u* specify a registration name using *-r*.
+
+By default snf-image-creator will perform a number of system preparation
+operations on the snapshot of the media and will shrink the last partition
+found, before extracting the image. Both can be disabled by specifying
+*--no-sysprep* and *--no-shrink* respectively.
+
+If *--print-sysprep* is defined, the program will exit after outputing a
+list of enabled and disabled system preparation operation appliable to this
+media source. The user can enable or disable specific *syspreps* when creating
+an image, using *-{enable,disable}-sysprep* options. You can specify those
+options multiple times to enable or disable multiple *syspreps*.
Running *snf-image-creator* with *--print-sysprep* on a raw file that hosts a
-debian system, I get the following output:
+debian system, we get the following output:
+
+.. _sysprep:
.. code-block:: console
Enabling recovery proc
Launching helper VM... done
Inspecting Operating System... found a(n) debian system
- Mounting image... done
-
+ Mounting the media read-only... done
+
Enabled system preparation operations:
cleanup-cache:
Remove all regular files under /var/cache
-
+
cleanup-log:
Empty all files under /var/log
-
+
cleanup-passwords:
Remove all passwords and lock all user accounts
-
+
cleanup-tmp:
Remove all files under /tmp and /var/tmp
-
+
cleanup-userdata:
Delete sensitive userdata
-
+
fix-acpid:
Replace acpid powerdown action scripts to immediately shutdown the
system without checking if a GUI is running.
-
+
remove-persistent-net-rules:
Remove udev rules that will keep network interface names persistent
after hardware changes and reboots. Those rules will be created again
the next time the image runs.
-
+
remove-swap-entry:
Remove swap entry from /etc/fstab. If swap is the last partition
then the partition will be removed when shrinking is performed. If the
swap partition is not the last partition in the disk or if you are not
going to shrink the image you should probably disable this.
-
+
use-persistent-block-device-names:
Scan fstab & grub configuration files and replace all non-persistent
device references with UUIDs.
-
+
Disabled system preparation operations:
cleanup-mail:
Remove all files under /var/mail and /var/spool/mail
-
+
remove-user-accounts:
Remove all user accounts with id greater than 1000
-
-
+
+
cleaning up...
-If I want your images to also have all normal user accounts and all mail files
-removed, you can create it specifying the *--enable-sysprep* option like this:
+If we want the image to have all normal user accounts and all mail files
+removed, we can create it specifying *--enable-sysprep* option like this:
.. code-block:: console
- $ snf-image-creator --enable-sysprep cleanup-mail,remove-user-accounts ...
+ $ snf-image-creator --enable-sysprep cleanup-mail --enable-sysprep remove-user-accounts ...
Dialog-based version
---------------------
+====================
+
+*snf-mkimage* receives the following options:
+
+.. code-block:: console
+
+ $ Usage: snf-mkimage [options] [<input_media>]
+
+ Options:
+ --version show program's version number and exit
+ -h, --help show this help message and exit
+ -l FILE, --logfile=FILE
+ log all messages to FILE
+
+If the input media is not specified in the command line, in the first dialog
+box the user will be asked to specify it. After the input media is examined and
+the program is initialized, the user will be given the choice to run
+*snf-mkimage* in *wizard* or *expert* mode.
+Wizard mode
+-----------
+
+When *snf-mkimage* runs in *wizard* mode, the user is just asked to provide the
+following basic information:
+
+ * Name: A short name for the image (ex. "Slackware")
+ * Description: An one-line description for the image (ex. "Slackware Linux 14.0 with KDE")
+ * Account: An *~okeanos* account email
+ * Token: A token corresponding to the account defined previously
+
+After confirming, the image will be extracted, uploaded to *pithos+* and
+registered to *~okeanos*. The user will also be given the choice to keep a local
+copy of it. For most users the functionality this mode provides should be
+sufficient.
+
+Expert mode
+-----------
+
+Expert mode allows the user to have better control on the image creation
+process. In the picture below the main menu can be seen:
+
+.. image:: /snapshots/main_menu.png
+
+In the *Customize* sub-menu the user can control:
+
+ * The system preparation operations that will be applied on the media
+ * Whether the image will be shrunk or not
+ * The properties associated with the image
+ * The configuration tasks that will run during image deployment
+
+In the *Register* sub-menu the user can provide:
+
+ * The credentials to login to *~okeanos*
+ * A pithos filename for the uploaded *diskdump* image
+ * A name for the image to be registered to *~okeanos* with
+
+By choosing the *Extract* menu entry the user can dump the image to the local
+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.
Creating a new image
---------------------
+====================
-Suppose you want to create a new ubuntu server image. Download the installation
-disk from the internet:
+Suppose you want to create a new Ubuntu server image. Download the installation
+disk from the Internet:
.. code-block:: console
$ wget http://ubuntureleases.tsl.gr/12.04.1/ubuntu-12.04.1-server-amd64.iso
+Verify that it has been downloaded correctly:
+
+.. code-block:: console
+
+ $ echo 'a8c667e871f48f3a662f3fbf1c3ddb17 ubuntu-12.04.1-server-amd64.iso' > check.md5
+ $ md5sum -c check.md5
+
Create a 2G sparce file to host the new system:
.. code-block:: console
$ truncate -s 2G ubuntu_hd.raw
-And install the ubuntu system on this file:
+And install the Ubuntu system on this file:
.. code-block:: console
$ sudo kvm -boot d -drive file=ubuntu_hd.raw,format=raw,cache=none,if=virtio \
- -cdrom ubuntu-12.04.1-server-amd64.iso
+ -m 1000 -cdrom ubuntu-12.04.1-server-amd64.iso
-After this, become root, activate the virtual environment you have installed
-snf-image-creator in, and use *snf-mkimage* to create and upload the image:
+.. note::
+
+ 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.
+
+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
+(e.g. install openssh-server) using the following command::
+
+ $ sudo kvm -m 1000 -drive file=linuxmint.raw,format=raw,cache=none,if=virtio
+
+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:
.. code-block:: console
$ snf-mkimage ubuntu_hd.raw
In the first screen you will be asked to choose if you want to run the program
-in *Wizand* or *Expert* mode. Choose *Wizard*.
+in *Wizard* or *Expert* mode. Choose *Wizard*.
.. image:: /snapshots/01_wizard.png
-Then you will be asked to provide a name, a description, an ~okeanos account
+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.
.. image:: /snapshots/06_confirm.png
-Choosing *YES* will create the image and upload it to your ~okeanos account.
-
+Choosing *YES* will create the image and upload it to your *~okeanos* account.
+
+Some caveats on image creation
+==============================
+
+Para-virtualized drivers
+------------------------
+
+*~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.
+
+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.
+
+Swap partitions
+---------------
+
+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.
+
+.. rubric:: Footnotes
+
+.. [#f1] https://wiki.archlinux.org/index.php/KVM#Paravirtualized_guests_.28virtio.29
projects / snf-image-creator / blobdiff