Understanding Server Software Packages

Server Software Packages are much like an installation package that you may be familiar with for other systems. This package system enables you to specify that certain features of the hardware and system be present (disk space, OS version, and so forth), and you can look for the existence of particular files and registry keys or set parameters. You may also specify variables that are substituted into the package when installation occurs to enable you to customize the package for several different target machines. Additionally, you may include the loading and unloading of NLMs and Java classes and the execution of specified scripts both before and after package installation.

A software package is made up of a set of components. You can have any number of components within a software package. Within a component, you can have any number of files and folders that are copied to the server.

About Installation Requirements

Before you can install a software package on the server, the server must satisfy the requirements that have been administered as part of the package. In addition to package requirements, each component may have its own set of requirements that must be fulfilled before it's installed. If the requirements are not met for a particular component, that component will not be installed.

Consequently, only portions of a software package may actually be installed on the server. Additionally, because of the logic placed in the components and the fact that the component is installed prior to the rules for the next component being processed, you can put in some rules in a subsequent component that check for the existence of a previous package component on the server. By doing this, you can have subsequent components fail and not be installed if a previous component has not been installed. You could, for example, have component 2 look for the existence of a file on the server that should have been installed if component 1 was successfully installed. If component 1 does not install properly, component 2 does not run because the file from component 1 is not found on the server.

Focusing on .SPK and .CPK Files

The specifications that you give are all stored in a file with the suffix of .SPK. This file is stored on the file system and contains the configuration information for all components of the package. The .SPK file cannot be sent to a server or installed on a server; it must first be compiled into a .CPK file. At compile time, the ConsoleOne snap-in takes the references to the files in the .SPK file and retrieves the files and places them into the .CPK file so that no references are in the file. All the data for the installation is compacted and stored into the single .CPK file. This complete file can then be used to install the features onto your servers.

The compiled .CPK file can be sent over to the servers via the TED distribution system, or it can be manually copied to those servers (through CDs, Jaz drives, a network, and so forth) and then executed locally. The TED system subscribers (see Chapter 6, "Setting Up Tiered Electronic Distribution," for more information) receive the .CPK file and, if the ZENworks for Servers 3 Policy Manager is running on the server, activate that agent to have it unpack and execute the .CPK file. This can also be done manually by copying the file to the server (or having it accessible from the server drivers, for example, on a CD-ROM) and then entering the command PACKAGE PROCESS <path to .CPK file>. This performs the unpacking and execution of the .CPK file.

Rollback

ZENworks for Servers 3 provides the capability to roll back an installation that has occurred via a .CPK file. The rollback can remove any installation changes that have occurred on the last applied package. You can perform several rollbacks to get back to previous packages. For example, if packages A, B, and C have been applied, you can roll back only C. And after package C has been rolled back, you can roll back package B.

When ZENworks for Servers 3 applies a package, it creates a rollback package in the working directory of the policy engine, under the ROLLBACK subdirectory. Each rollback file is itself a .CPK file and is named by a GUID (globally unique identifier). When you request that a rollback occur, the rollback .CPK file is processed and then deleted. Rerunning the same installation .CPK file (unchanged version) does not create multiple rollback files. But if you recompile the .SPK file, a new .CPK file is created, even if you give it the same name, and the package is installed again on the server even though the .SPK file was unchanged.

You can request a rollback by going to the ZENworks for Servers 3 console and entering the command package rollback. Additionally, you can go through the browser-based management system and request that a rollback occur on the server.

Creating and Managing .SPK Files in ConsoleOne

You create and manage .SPK files in ConsoleOne. The ZENworks for Servers 3 install establishes a new namespace in ConsoleOne to manage these packages. A namespace in ConsoleOne results in a new rooted entry under your My World icon, at the same level as NDS in the ConsoleOne hierarchy display in the left panel.

When you create or insert an .SPK file, an entry is placed in ConsoleOne configuration files that, when ConsoleOne comes up, displays the known software packages without requiring the namespace to search all possible drives to find the .SPK file. Consequently, if you delete the .SPK file from the file system, ConsoleOne is not aware of this and continues to display the software package entry in the Server Software Packages namespace. But if you attempt to modify the package parameters, an error occurs because the file is not found. You need to manually delete the entry from ConsoleOne by choosing the Remove Package entry from the menu.

NOTE

Choosing the Remove Package entry does not remove the .SPK or .CPK files that are associated with the package. You also need to manually remove them from the file system if you no longer want to keep the packages.

Discussing Installation Failures

Should the processing of a .CPK run into problems installing the components (for example, running out of file space), the package installation is aborted, an error log is created, and a message is displayed. The components of the package that were installed are automatically rolled back and uninstalled.