28.5 Preboot Strategies

The following sections present possible approaches to using Preboot Services. Use the following sections to determine which procedures to perform. The steps are documented in subsequent sections.

28.5.1 Automating Updates and Installations

You can automate Linux installations and software updates using Preboot Services in the following ways:

  • SUSE Linux installation: The AutoYaST bundle can automate installation of SUSE Linux on a Linux device.

  • Red Hat Linux installation: The kickstart bundle can automate installation of Red Hat Linux on a Linux device.

  • ZENworks script execution: The ZENworks Script bundle can automate execution of any ZENworks script on a Linux device, including imaging commands.

  • Device imaging: The ZENworks Imaging bundle can be used to place an image on a Linux device.

  • Imaging multiple devices: The ZENworks Multicast bundle can be used to place an image on multiple Linux devices with one pass of the image file over the network, such as in resetting lab devices.

All you need to do to accomplish any of these actions is to create and configure one of the five Preboot bundle types, then assign the bundle to the desired devices.

When a device boots, the assigned bundle is automatically applied before the device’s operating system starts.

You can also manually accomplish these tasks per device using the Preboot Services Menu’s Start ZENworks Imaging Maintenance option to access the bash prompt, if you have enabled the Preboot Services Menu for the device. Or, you can use a Preboot Services bootable CD or DVD, which does not require PXE to be enabled on the device. For more information, see Section 30.1.2, Performing Manual Imaging Tasks.

28.5.2 Creating, Installing, and Restoring Standard Images

As new devices are purchased and before deploying them, you can install a standard software platform and enable the device for future unattended reimaging.

  1. Create a model device of each type that you intend to deploy.

  2. Create an image of each model device on a ZENworks Linux Management imaging server. For more information, see Manually Taking an Image of a Device.

    These images should include the Novell ZENworks Linux Management Imaging Agent (novell-zslnx).

  3. Optionally, you can create a preboot imaging bundle for this image. This allows the image to be assigned automatically for later use.

  4. If you are using Preboot Services, install ZENworks Linux Management on your imaging server. For more information, see Section 29.1, Preparing a Preboot Services Server.

    or

    If you are using a bootable CD or DVD, or a ZENworks partition, create a boot CD or DVD that points to the ZENworks Linux Management imaging server where the model images are stored. For more information, see Section 29.2, Setting Up the Preboot Services Methods.

As each new device comes in, do the following if you are using Preboot Services:

  1. Check to see if the device is PXE capable. Enable PXE if it isn’t enabled by default. For more information, see Section 29.6, Enabling PXE on Devices.

  2. Physically connect the device to the network.

  3. Boot the device from the Preboot Services imaging server.

If you are not using Preboot Services, boot the device with the imaging boot CD or DVD and consider installing the ZENworks partition to enable auto-imaging without needing to supply the CD or DVD. For more information, see Step 3 of Section 29.7.2, Enabling a Device for Imaging Operations. After you have installed the partition, reboot the device from the ZENworks partition.

28.5.3 Reimaging Corrupted Devices

Without data loss or undue disruption to users, you can fix devices that have become misconfigured or corrupted.

  1. When a device needs to be fixed, have the user back up any files to the network that he or she wants to keep (if possible).

  2. Create and/or assign an appropriate imaging bundle to the device.

  3. If it is a device with a ZENworks partition or it is PXE-enabled, the user should boot the device from the ZENworks partition or the Preboot Services imaging server (via PXE) to find and execute the assigned bundle. If you are using PXE, make sure that Preboot Services is installed on your imaging server. For more information, see Section 30.0, Using Preboot Services.

    or

    If the device does not have a ZENworks partition and is not PXE-enabled, the user should boot the device with the imaging boot CD or DVD and restore the appropriate images manually.

  4. After the image is laid down, restore any user files that were backed up to the network.

28.5.4 Restoring Lab Devices to a Clean State

You can restore devices to a clean state, removing any changes or additions made since the last time you restored the image on that device. This is useful for updating lab devices.

The following steps assume that the devices are unregistered.

  1. Create an image of a clean model device and store it on a ZENworks Linux Management imaging server. For more information, see Manually Taking an Image of a Device.

  2. If you are using Preboot Services, make sure that ZENworks Linux Management is installed on your imaging server. For more information, see Section 29.1, Preparing a Preboot Services Server.

  3. If you are using Preboot Services and the devices are PXE capable, make sure that PXE is enabled. For more information, see Section 29.6, Enabling PXE on Devices.

    or

    If you are not using Preboot Services or the Linux partition, create an imaging boot CD or DVD that points to the ZENworks Linux Management imaging server where the clean image is stored. For more information, see Section 29.2, Setting Up the Preboot Services Methods.

Deploy each lab device as follows:

  1. Physically connect the device to the lab network.

  2. If you are using Preboot Services, boot the device from the Preboot Services imaging server.

    or

    If you are not using Preboot Services, boot the device with the imaging boot CD or DVD and install the ZENworks partition. For more information, see Step 3 of Section 29.7.2, Enabling a Device for Imaging Operations. After you have installed the partition, reboot the device from the ZENworks partition.

  3. At the end of each lab session, assign the Preboot bundle to the lab devices.

  4. Reboot each device and let it be auto-imaged by its assignment to a ZENworks Preboot bundle.

28.5.5 Setting Up Devices for Future Reimaging

With minimal disruption to users, you can enable existing devices for possible future reimaging.

This process might need to be phased in by local administrators. Each administrator can do the following:

  1. Install the Novell ZENworks Linux Management Imaging Agent (novell-zislnx) on each device.

  2. If the devices are PXE capable, make sure PXE is enabled (see Section 29.6, Enabling PXE on Devices) and make sure that ZENworks Linux Management is installed on your imaging server (see Section 29.1, Preparing a Preboot Services Server).

    or

    Prepare a few sets of imaging CDs or DVDs that users can use when they run into trouble (see Section 29.2, Setting Up the Preboot Services Methods). These devices should point to an imaging server that contains the same clean images used for new devices.

  3. If a user runs into trouble, use the strategy for reimaging corrupted devices. For more information, see Section 28.5.3, Reimaging Corrupted Devices.

28.5.6 Multicasting Device Images

The following sections explain the multicasting images feature:

For instructions on using multicasting, see Section 30.2, Multicasting Images.

Understanding Multicasting

Multicasting is a way to send the same image to multiple devices without sending that image multiple times across the network. It is done by inviting participants to join a multicast session. Multicasting is similar to broadcasting on the network, because you send the image once to the network and only those devices belonging to the multicast session can see and receive it. This saves on network bandwidth usage.

For example, if you have 10 devices in the multicast session and the image is 3 GB in size, your network experiences only 3 GB of network traffic to image all 10 devices. Without multicasting, the network experiences 30 GB of network traffic to image all 10 devices individually.

The devices to be imaged must be physically connected to the network. They can be devices with existing operating systems of any kind, or they can be new devices with no operating system installed.

IMPORTANT:For multicasting to work properly, all routers and switches on the network must have their multicast features configured. Otherwise, multicast packets might not be routed properly.

Multicasting can be done automatically or manually:

Automatic Multicasting

In the ZENworks Control Center, multicasting is accomplished by configuring a Multicast bundle. The bundle contains a base image that is taken previously from a device and is stored on an imaging server. This base image is applied to all multicast session participants.

When using a Preboot bundle to perform multicasting, the imaging server is the session master, which sends the .zmg image file to the session participants. The novell-pbserv daemon is used in this process. All problems are reported and displayed on the session master device.

For more information, see Section 30.2, Multicasting Images.

Manual Multicasting

At a bash prompt, you can enter commands to configure and initiate a multicasting session. You enter the appropriate commands on a bash prompt at each device, specifying one of them to be the session master. An image of the session master’s hard drive is sent to each of the session participants.

For more information on the imaging commands, see Section E.5, Session (Multicast) Mode (img session).

If you plan to set up multicasting by visiting each device, you need either an imaging boot CD or DVD, or the devices must be PXE-enabled. For more information, see Section 29.2, Setting Up the Preboot Services Methods.

Practical Uses For Multicasting

Multicasting is ideal for labs, classrooms, and staging areas, or for any place where you need to quickly create the same configuration on multiple devices, instead of taking the time to set up each device individually.

Benefits of Multicasting Images

Multicasting is the way to use ZENworks Imaging Engine for mass reimaging with the least amount of overhead. It is useful if you have one device with a clean software configuration that you want to duplicate on several other devices, or if you have a single image that you want to set up on multiple devices.

Limitations of Multicasting Images

One significant limitation of using multicast without installing any ZENworks Linux Management software is that it results in a set of devices that have duplicate network identities. The IP addresses (if the network is using static IP addressing) and device hostname are all the same and can cause conflicts if deployed on the network without change.

For a handful of devices, this might not be a problem. But for a larger number of devices, you should install the Novell ZENworks Linux Management Imaging Agent (novell-zislnx) on each device before doing the multicast (see Section 29.7.2, Enabling a Device for Imaging Operations). The Imaging Agent saves the device’s network identity settings before the multicast session and restores them afterwards.

Automatic Multicasting Example

To automatically multicast an image to multiple devices using the ZENworks Control Center:

  1. In the ZENworks Control Center, create a Multicast bundle using a wizard.

  2. Specify the source image for the bundle.

    You can multicast an existing image from your imaging server.

  3. Configure the trigger for multicasting the bundle, as in the following examples:

    Client count: When the specified number of clients specified in the bundle have booted and registered, the multicast session begins.

    Time count: When the specified length of time has passed with no new clients having registered, the multicast session begins regardless of the number of client participating.

    The first trigger to be realized causes the multicast session to begin.

  4. Assign the Multicast bundle to the desired devices.

    The ZENworks Control Center provides a way to enable or disable a Multicast bundle, allowing you to temporarily stop the bundle from executing. This is more efficient than unasssigning the bundle from many devices.

  5. Wait for the trigger to happen.

    Each device booting into the session has its boot process delayed until the session begins, which is determined by fulfillment of one of the triggers.

    The multicast happens automatically when a device assigned to the Multicast bundle boots, according the configuration you set up for the Multicast bundle and for the devices you assigned to the bundle. This bundle is applied to each session device before it boots its operating system. The ZENworks Multicast bundle is sent over the wire just once, using the multicast capability of your network, and executed simultaneously on all participating devices.

28.5.7 Configuring Dell Linux Devices

Certain Dell computer models can be automatically configured using ZENworks Preboot Services. You can configure the following for Dell devices:

  • BIOS/BMC/DRAC 5 Configuration File: You can use syscfg to auto-generate a BIOS, BMS, or DRAC 5 file with a specific configuration for the device.

  • RAID Configuration Script: You can use a supplied example script to configure your RAID settings for the device.

  • DRAC Configuration File: You can run a supplied script to create your DRAC 4 or earlier configuration file.

  • Dell Utility Partition: You can create a Dell utility partition when imaging the device, including setting its size, specifying the target disk, indicate whether to use a specific Dell utility partition file, and indicate whether to overwrite any existing utility files.

  • Preboot Bundle: You can immediately perform an operating system installation after configuring the Dell device by specifying the Preboot bundle containing that installation configuration.

The above options are only for configuring, not for updating these settings. These configurations are applied to the Dell device when it boots and uses the Dell Configuration Preboot bundle that it is assigned to.

To properly configure Dell devices, you can also do the following: