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6.  Advanced Package Creation Techniques Accommodating Relocation Walking Base Directories Example--A request Script That Walks a Relative Parametric Path  Previous   Contents   Next 
   
 

Supporting Relocation in a Heterogeneous Environment

The original concept behind System V packaging assumed one architecture per system. The concept of a server did not play a role in the design. Now, of course, a single server may provide support for several architectures, which means there may be several copies of the same software on a server, each for a different architecture. While Solaris packages are sequestered within recommended file system boundaries (for example, / and /usr), with product databases on the server as well as each client, not all installations necessarily support this division. Certain implementations support an entirely different structure and imply a common product database. While pointing the clients to different versions is straightforward, actually installing System V packages to different base directories can introduce complications for the administrator.

When you design your package, you should also consider the common methods administrators use for introducing new software versions. Administrators often seek to install and test the latest version side-by-side with the currently installed version. The procedure involves installing the new version to a different base directory than the current version and directing a handful of non-critical clients to the new version as a test. As confidence builds, the administrator redirects more and more clients to the new version. Eventually, the administrator retains the old version only for emergencies and then finally deletes it.

What this means is that packages destined for modern heterogeneous systems must support true relocation in the sense that the administrator may put them any reasonable place on the file system and still see full functionality. The Solaris 2.5 and compatible releases provide a number of useful tools which allow multiple architectures and versions to install cleanly to the same system. Solaris 2.4 and compatible versions also support true relocation but accomplishing the task is not quite as obvious.

Traditional Approach

Relocatable Packages

The System V ABI implies that the original intention behind the relocatable package was to make installing the package more convenient for the administrator. Now the need for relocatable packages goes much further. Convenience is not the only issue, rather it is quite possible that during the installation an active software product is already installed in the default directory. A package that is not designed to deal with this situation either overwrites the existing product or fails to install. However, a package designed handle multiple architectures and multiple versions can install smoothly and offer the administrator a wide range of options that are fully compatible with existing administrative traditions.

In some ways the problem of multiple architectures and the problem of multiple versions is the same. It must be possible to install a variant of the existing package side by side with other variants, and direct clients or standalone consumers of exported file systems to any one of those variants, without degraded functionality. While Sun has established methods for dealing with multiple architectures on a server, the administrator may not adhere to those recommendations. All packages need to be capable of complying with the administrators' reasonable wishes regarding installation.

Example-A Traditional Relocatable Package

This example shows what a traditional relocatable package may look like. The package is to be located in /opt/SUNWstuf, and its pkginfo file and pkgmap file might look like this.

The pkginfo File

# pkginfo file
PKG=SUNWstuf
NAME=software stuff 
ARCH=sparc
VERSION=1.0.0,REV=1.0.5
CATEGORY=application
DESC=a set of utilities that do stuff
BASEDIR=/opt
VENDOR=Sun Microsystems, Inc.
HOTLINE=Please contact your local service provider
EMAIL=
MAXINST=1000
CLASSES=none
PSTAMP=hubert990707141632

The pkgmap File

: 1 1758
1 d none SUNWstuf 0775 root bin
1 d none SUNWstuf/EZstuf 0775 root bin
1 f none SUNWstuf/EZstuf/dirdel 0555 bin bin 40 773 751310229
1 f none SUNWstuf/EZstuf/usrdel 0555 bin bin 40 773 751310229
1 f none SUNWstuf/EZstuf/filedel 0555 bin bin 40 773 751310229
1 d none SUNWstuf/HRDstuf 0775 root bin
1 f none SUNWstuf/HRDstuf/mksmart 0555 bin bin 40 773 751310229
1 f none SUNWstuf/HRDstuf/mktall 0555 bin bin 40 773 751310229
1 f none SUNWstuf/HRDstuf/mkcute 0555 bin bin 40 773 751310229
1 f none SUNWstuf/HRDstuf/mkeasy 0555 bin bin 40 773 751310229
1 i pkginfo 348 28411 760740163
1 i postinstall 323 26475 751309908
1 i postremove 402 33179 751309945
1 i preinstall 321 26254 751310019
1 i preremove 320 26114 751309865

This is referred to as the traditional method because every package object is installed to the base directory defined by the BASEDIR parameter from the pkginfo file. For example, the first object in the pkgmap file is installed as the directory /opt/SUNWstuf.

Absolute Packages

An absolute package is one that installs to a particular root (/) file system. These packages are difficult to deal with from the standpoint of multiple versions and architectures. As a general rule, all packages should be relocatable. There are, however very good reasons to include absolute elements in a relocatable package.

Example-A Traditional Absolute Package

If the SUNWstuf package was an absolute package, the BASEDIR parameter should not be defined in the pkginfo file, and the pkgmap file would look like this.

The pkgmap File

: 1 1758
1 d none /opt ? ? ?
1 d none /opt/SUNWstuf 0775 root bin
1 d none /opt/SUNWstuf/EZstuf 0775 root bin
1 f none /opt/SUNWstuf/EZstuf/dirdel 0555 bin bin 40 773 751310229
1 f none /opt/SUNWstuf/EZstuf/usrdel 0555 bin bin 40 773 751310229
1 f none /opt/SUNWstuf/EZstuf/filedel 0555 bin bin 40 773 751310229
1 d none /opt/SUNWstuf/HRDstuf 0775 root bin
1 f none /opt/SUNWstuf/HRDstuf/mksmart 0555 bin bin 40 773 751310229
1 f none /opt/SUNWstuf/HRDstuf/mktall 0555 bin bin 40 773 751310229
1 f none /opt/SUNWstuf/HRDstuf/mkcute 0555 bin bin 40 773 751310229
1 f none /opt/SUNWstuf/HRDstuf/mkeasy 0555 bin bin 40 773 751310229
1 i pkginfo 348 28411 760740163
1 i postinstall 323 26475 751309908
1 i postremove 402 33179 751309945
1 i preinstall 321 26254 751310019
1 i preremove 320 26114 751309865

In this example, if the administrator specified an alternate base directory during installation, it would be ignored by the pkgadd command. This package always installs to /opt/SUNWstuf of the target system.

The -R argument to the pkgadd command works as expected. For example,

pkgadd -d . -R /export/opt/client3 SUNWstuf

installs the objects in /export/opt/client3/opt/SUNWstuf; but that is the closest this package comes to being relocatable.

Notice the use of the question mark (?) for the /opt directory in the pkgmap file. This indicates that the existing attributes should not be changed. It does not mean "create the directory with default attributes," although under certain circumstances that may happen. Any directory that is specific to the new package must specify all attributes explicitly.

Composite Packages

Any package containing relocatable objects is referred to as a relocatable package. This can be misleading because a relocatable package may contain absolute paths in its pkgmap file. Using a root (/) entry in a pkgmap file can enhance the relocatable aspects of the package. Packages that have both relocatable and root entries are called composite packages.

Example-A Traditional Solution

Assume that one object in the SUNWstuf package is a startup script executed at run level 2. The file /etc/rc2.d/S70dostuf needs to be installed as a part of the package, but it cannot be placed into the base directory. Assuming that a relocatable package is the only solution, the pkginfo and a pkgmap might look like this.

The pkginfo File

# pkginfo file
PKG=SUNWstuf
NAME=software stuff 
ARCH=sparc
VERSION=1.0.0,REV=1.0.5
CATEGORY=application
DESC=a set of utilities that do stuff
BASEDIR=/
VENDOR=Sun Microsystems, Inc.
HOTLINE=Please contact your local service provider
EMAIL=
MAXINST=1000
CLASSES=none
PSTAMP=hubert990707141632

The pkgmap File

: 1 1758
1 d none opt/SUNWstuf/EZstuf 0775 root bin
1 f none opt/SUNWstuf/EZstuf/dirdel 0555 bin bin 40 773 751310229
1 f none opt/SUNWstuf/EZstuf/usrdel 0555 bin bin 40 773 751310229
1 f none opt/SUNWstuf/EZstuf/filedel 0555 bin bin 40 773 751310229
1 d none opt/SUNWstuf/HRDstuf 0775 root bin
1 f none opt/SUNWstuf/HRDstuf/mksmart 0555 bin bin 40 773 751310229
1 f none opt/SUNWstuf/HRDstuf/mktall 0555 bin bin 40 773 751310229
1 f none opt/SUNWstuf/HRDstuf/mkcute 0555 bin bin 40 773 751310229
1 f none opt/SUNWstuf/HRDstuf/mkeasy 0555 bin bin 40 773 751310229
1 d none etc	? ? ?
1 d none etc/rc2.d ? ? ?
1 f none etc/rc2.d/S70dostuf 0744 root sys 450 223443
1 i pkginfo 348 28411 760740163
1 i postinstall 323 26475 751309908
1 i postremove 402 33179 751309945
1 i preinstall 321 26254 751310019
1 i preremove 320 26114 751309865

There is not much difference between this approach and that of the absolute package. In fact, this would be better off as an absolute package--if the administrator provided an alternate base directory for this package, it would not work!

 
 
 
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