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CT320: Network and System Administration

Software Installation

Colorado State University
Computer Science Department

Original slides from Dr. James Walden at Northern Kentucky University.

Software Installation

• Customization
  • Select options, e.g., language.
  • Select file set.
• Install new files in appropriate locations.
• Modify existing configuration files.
• Make software available to user.
  • Shell configuration ($PATH, etc.)
  • GUI configuration (menu, icons, etc.)

What’s the problem?

• What prerequisites does your software have?
  • What prereqs do your prereq packages have?
• How do you handle conflicts?
  • What if two programs install/modify same file?
• How do you handle upgrades?
  • What if user has customized configuration?
  • What if ownerships/permissions have changed?
  • What if user needs old and new versions?
  • What if a package becomes obsolete?
• How do you uninstall software?

Package Manager Features

Any package manager must have:

• Build management (build from source)
• Dependency tracking (package A requires package B)
• Querying (What’s installed?)
• Reversibility (uninstall)
• Verification (Has this package been tampered with?)
• Version control (gcc 4.8 vs. gcc 4.9)

UNIX Package Management Systems

• Debian: dpkg and apt (advanced package tool)
  • Ubuntu: same as above, same packages, too
• Solaris: pkg-add packaging system
• Gentoo: portage with emerge command
• Slackware: installpkg manages .tgz files
• RedHat: rpm (redhat package manager) packaging system.
  • up2date: RHEL interface to RPM
  • urpmi: Mandriva interface to RPM
  • yast: SuSE interface to RPM
  • yum: Fedora interface to RPM

Package

A package, in general, is a encapsulation of a program or programs. It contains:

• executable files
• required data files
• icons
• man pages
• dependency information
• install/update/remove procedures
• description, pointer to developers, etc.
• checksums/hashes

More than one file

Some packages contain many programs. The Debian coreutils package contains 232 files, including these programs:

deb

Debian (and hence Ubuntu (and hence Xubuntu)) uses *.deb files to hold packages.

dpkg

On Ubuntu, the most primitive package manager is Debian’s dpkg. I rarely use it directly.

Wrappers

There are many programs that provide a better interface than dpkg:

• apt: command-line wrapper around dpkg
• apt-get: roughly the same
• aptitude: roughly the same
• synaptic: graphical interface to install & remove packages
• software-center: a very friendly interface to look for new packages, like the Google Play Store
• update-manager: graphical interface that looks for updates, like Windows Update. Often run from cron.

Using apt-get

1. Install
2. Uninstall
3. Upgrade
4. Query
5. Verify

Installing a Package

1. Check the package and the files it wants to install.
2. Perform preinstallation tasks.
3. Uncompress the files and copy them in the proper locations
4. Perform post-processing tasks
5. Update the database

Install Example

% sudo apt-get install zoo
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  zoo
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 74.5 kB of archives.
After this operation, 169 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu/ vivid/universe zoo amd64 2.10-27 [74.5 kB]
Fetched 74.5 kB in 0s (225 kB/s)
Selecting previously unselected package zoo.
(Reading database ... 225219 files and directories currently installed.)
Preparing to unpack .../archives/zoo_2.10-27_amd64.deb ...
Unpacking zoo (2.10-27) ...
Processing triggers for man-db (2.7.0.2-5) ...
Setting up zoo (2.10-27) ...

Upgrading a Package

• Uninstall + install, retaining configuration files.
  • Will install a package if no older version.
  • Will remove all older versions.

Uninstalling a Package

Remove a package, leave configuration files behind.

% sudo apt-get remove zoo
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  zoo
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 169 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 225225 files and directories currently installed.)
Removing zoo (2.10-27) ...
Processing triggers for man-db (2.7.0.2-5) ...

Uninstalling a Package

Completely removes package from system, including configuration files.

% sudo apt-get purge zoo
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  zoo*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 169 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 225225 files and directories currently installed.)
Removing zoo (2.10-27) ...
Processing triggers for man-db (2.7.0.2-5) ...

Dependencies

For example, a number of packages depend upon the cups package. Removing cups will remove several other packages:

% sudo apt-get remove cups
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  bluez-cups cups hplip printer-driver-gutenprint printer-driver-hpcups
  printer-driver-postscript-hp printer-driver-splix
0 upgraded, 0 newly installed, 7 to remove and 0 not upgraded.
After this operation, 5,688 kB disk space will be freed.
Do you want to continue? [Y/n] n
Abort.

Dependency Resolution

• Higher level tools handle dependencies
• Automatic resolution + downloading.
  • Find dependencies in package headers.
  • Download dependencies, check their headers.
  • Repeat.
  • Install after all packages are downloaded.

Just Testing

Verify that all installed files match the md5sum.

% sudo dpkg --verify
??5?????? c /etc/sudoers
??5?????? c /etc/default/rcS
??5??????   /usr/bin/xdg-open

Querying the Database

• List installed packages: dpkg --get-selections
• Installed vim packages: dpkg --get-selections 'vim*'
• Installed packages by size:
  dpkg-query -Wf '${Installed-Size} ${Package}\n' | sort -n
• What package provides date: dpkg -S /bin/date
• What files are in the coreutils package: dpkg -L coreutils
• Tell me about the gcc package: apt-cache show gcc

Maintenance

Do this every week or so:

    % sudo apt-get update
    % sudo apt-get dist-upgrade
    % sudo apt-get autoremove

upgrade vs. dist-upgrade

apt-get upgrade

apt-get dist-upgrade