UCS 2.4 - Univention

11.2 UCS updates
system version which have not yet been installed, these are installed as well so that the system is kept
up-to-date. The security updates are downloaded from the set repository server. This is entered in the
Univention Configuration Registry variable repository/online/server. The web proxy settings of
the system are taken into account when accessing the server.
Alternatively, security updates can be downloaded as .tar archives and installed using the
univention-security-update local command. These variants can, however, only be used on
repository servers. An example usage is:
univention-security-update local --file ucs-security-2.2sec1.tar.gz
In advance it must be checked whether the archive was downloaded completely and correctly. This can
be done using the md5sum command, which creates a unique check sum for the archive. The check sums
of all the archives can be found under the specified URL for comparison. If the MD5 sum is correct, the
security update can be imported with the named command. Firstly the local repository is updated and then
security update is installed on the system.
Security updates for UCS usually contains several packages to correct security risks and serious errors.
This eliminates the need to import new packages individually time and time again. In certain circumstances
it may be necessary to retrieve the corrections for certain packages as soon as possible. This is done using
Univention hotfixes. As soon as a package is created with the corresponding correction and this has been
tested, it is provided in the hotfix repository and the update announced per e-mail. Univention hotfixes can
be imported on UCS systems from this repository using the command univention-actualise. The
Univention Configuration Registry variable repository/online/hotfixes needs to be set to yes for
the inclusion of the hotfix repository.
11.2.2 UCS release updates
An important part in the development of UCS is the update-ability. This means that a UCS environment
can be updated to the next versions without the need for extensive interventions. It is usually not necessary
for the security updates available for the previous versions to have been imported.
Parallel to the installation DVDs for a new UCS release, Univention also publishes update DVDs in the form
of ISO images for the update. Alternatively to the update via an update DVD, this can also be performed
via the online repository. A changelog document is published for each release update listing the packages
which have been updated and the reason for their updating or additional functions. In addition, a document
is published with the release notes containing important information which must be observed.
As with security updates, in a UCS release update the packages for new UCS version are imported in a
repository using univention-repository-update before the remaining UCS systems are updated.
If the online repository should be used, the system update can be begun immediately. When importing
a release update in a UCS environment, the domain controller master should be the first system to be
updated. Once the release update has been imported, the respective system must be rebooted.
It is recommended to update a UCS system directly on the console or using the Univention Management
Console Updating over a network connection (e.g., SSH session) is not advisable as this may result in the
update procedure being cancelled. If updating should occur over a network connection nevertheless, it
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