APK Installation Guide For Ubuntu Linux distributions.

Files

• apk-ver-linux-ub.tar.gz - the appliance kit
• domu-linux-lver.tar.gz - para-virtualized kernel and modules library

Compatibility

The apk-*-linux-ub versions are compatible with the following OS distros:

• Ubuntu (versions 6 and 7 verified, may work on older distros as well)
• Should work on Debian (not verified)

To install APK you need either:

* an old AppLogic appliance image (with or without APK installed) * a vanilla installation of the OS distro

The image must be with the ext3 file system, if the APK-provided kernel and initrd files will be used.

Preparing the image

The following steps may vary, depending on how the OS was originally installed. They are not performed by the APK setup script, and are left to the discretion of the operator, because some of them are invasive and may be destructive, if accidentally done on a live system (rather than on the image being prepared) - therefore running them in an automated script may be inadvisable.

Skip any steps that are not appropriate.

• make sure the disk image is an ext3 file system. If the OS was installed as ext2, run 'tune2fs -j' on it turn it into ext3. To use ext2 (or any filesystem other than ext3) the initrd file shipped with APK has to be re-built.
• edit the network configuration file (/etc/network/interfaces) and remove all interfaces except 'lo'.
• edit the etc/fstab file and change the name of the root device to be /dev/hda1. This is important, the installer will also check and print a warning if it finds the root device is specified by label or by UUID.
• delete the kernel package, ignoring dependencies (optional, to save disk space on the boot volume)
• older Debian and Ubuntu distros: ensure that the iproute package is installed (it isn't present by default on older distros).
• un-install any OS services that will not be used

NOTE: After it is cleaned up, the volume may be 'shrunk' to produce a smaller boot volume image for the appliance, however ensure that at least 10-15MB of free space is left, to have space for installing the XEN DomU kernel and APK, as well as to have some headroom for log files, temporary files, etc.

APK uses a simple initial ramdisk image (initrd) created with the RedHat 'nash' bootstrap program. It does not load any kernel modules and its only purpose is to set up the ramdisk-based /dev/ directory for the 'udev' program an populate it.

It works fine in booting a Ubuntu-based virtual appliance and there is no need to create a "ubuntu-style" initrd image for the appliance. The Ubuntu 6/7 initrd images are heavier and have more advanced functionality, which isn't necessary in most appliances. If desired, a Ubuntu-specific initrd file can be created and used. Simply edit the /boot/grub/menu.lst file to point to an alternate initrd image. Note that this change will have to be re-applied should you re-install APK in the future. Installing APK

Have the OS image mounted in your file system. If the image is already installed as a volume on an AppLogic grid, it can be accessed using the 'vol manage' command. Copy the APK files to the /tmp directory on the image itself or to a temporary directory on the host where the image is mounted. If the image is already on a grid, copy the files to the image itself using the Web interface. (If not doing this on a grid: note that the following operations must be done as user 'root'.)

Transitional Note: The prototype Ubuntu appliance created for AppLogic 2.3.0 does not have the 'wget' program installed. APK requires wget for its operation. Make sure that 'wget' is installed.

Un-pack the DomU kernel and the APK binary archive into the root directory of the image, .e.g:

  cd /mnt/vol
  tar -zxf tmp/domu-linux-2.6.16.33.tar.gz
  tar -zxf tmp/apk-2.0.6-ub.tar.gz

The setup script will be unpacked into the ./tmp directory. Run the setup script::

  tmp/apk-install

Note that the APK-supplied init scripts no longer support appliance-specific scripts installed in "/appliance". If it is present, the install script will stop and prompt for user input. If no appliance-specific customization was done in this directory (i.e., its contents are the same or similar to what is found on LUX), it is safe to delete it. All of the standard functionality that used to be installed there is now provided by APK. Otherwise, choose "save to /tmp" and proceed with the install. See details on customizing APK further below.

The setup script (and the tar files, if they were copied to the image itself) can be removed now:

  rm tmp/apk-install tmp/domu-linux-*.tar.gz tmp/apk-*.tar.gz

Un-mount the image and import it to your AppLogic grid (or just close the 'vol manage' shell, if the image was already on your grid and was edited using 'vol manage').

If the image was that of an existing appliance: edit the class (using the GUI editor) and remove the kernel and initrd file names. Set the configuration mode to 'dhcp'.

Customizing Appliance Behavior - Quick Reference

For full details please refer to the User Guide.

Appliance Init Configuration

If the file /etc/sysconfig/applogic_init is present, the APK init script reads it as a shell include script (with the "." command). The following parameters can be defined in /etc/sysconfig/applogic_init:

APK_AUTH_KEY_PATH

location in which to store the appliance SSH access public key. The '3t comp ssh' command connects to appliances using the matching private key. Default is /root/.ssh. If set to an empty string, the key will not be stored anywhere. If the specified location is an existing file, its owner and permissions will be preserved. Otherwise the file will be created with owner 'root'.

APK_CONFIG_FILES

space-separated list of files to which to apply appliance properties. This replaces the config file list specified in the "Edit Class" dialog in the GUI (for appliances that are not using APK). An appliance outfitted with APK will use the APK_CONFIG_FILES list found on the appliance itself, not the list specified in the GUI. Important: if installing APK in an existing appliance - check in the class descriptor (using the editor GUI) for the presence of configuration files in the "Config Files" tab found in the View Class / Edit Class dialog. Transfer the list of files to the APK_CONFIG_FILES setting in the appliance.

Important: the /etc/sysconfig/applogic_init file is executed before any configuration data is retrieved or or applied, therefore the script cannot rely on the presence of any of the appliance's configuration files.

Example /etc/sysconfig/applogic_init:

   APK_CONFIG_FILES=/etc/httpd/conf.d/myconfig.conf
   APK_AUTH_KEY_PATH=/root/.ssh/alternate_keys

Appliance Post-start Check

If the file /etc/sysconfig/applogic_appliance is present, the APK "late init" script reads it as a shell include script (with the "." command), after all services on the appliance have been started. The return status from the script indicates whether the appliance is to be considered "started OK" or "failed". If the script prints a message to stderr and returns an error, the last line from this message will be used as the error message sent to the controller.

Example post-start check file, for a Web server appliance - verifies that the server is up and responds to HTTP GET to the home page:

if ! wget -q -O /dev/null http://localhost/ ; then
   echo "start failed - Web server is not responding" >&2
   return 1
fi
return 0

Important: some appliances in the system catalog use a customized script located in /appliance to initialize services. This is no longer supported. This directory is deleted when APK is installed, to keep the root directory structure clean and compliant with the Filesystem Hierarchy Standard. One could move the code from such scripts to /etc/sysconfig/applogic_appliance, to emulate the old behavior but this is not the intention of the post-start check file and is not recommended. Instead, an installed service should have its own init script and in general should be able to operate entirely outside of AppLogic.

-- BeckyH - 30 Apr 2008