Maintainance

Updating the software

This section explains how to use aptitude upgrade and kde-update-notifier.

Using aptitude is really simply. To update a system you need to execute two commands on the command line as root: aptitude update (updates the lists of available packages) and aptitude upgrade (upgrades the packages for which an upgrade is available).

Instead of using the command line you can also use kde-update-notifier. FIXME: Explain how to use kde-update-notifier, best with screenshots.

It is also a good idea to install cron-apt and apt-listchanges and configure them to send mail to an address you are reading.

cron-apt will notify you once a day via email, which packages need an update. It does not install these updates, but downloads them (usually in the night), so you don't have to wait for the download, when you do aptitude upgrade.

apt-listchanges can send new changelog entries to you.

Keep yourself informed about security updates

Running cron-apt as described above is a good way to learn that for an installed package a security update is available. Another way to get informed about security updates is to subscribe to the Debian security-announce mailinglist, which has the benefit of also informing what the security update is about. The downside (compared to cron-apt) is that it also includes information about updates for packages which aren't installed.

Backup Management

For the backup management point your browser to https://www/slbackup-php. Please note that you have to access this site via ssl, since you have to enter the root password there. If you try to access this site without using ssl it will fail.

Per default the tjener will backup /skole/tjener/home0, /etc/, /root/.svk and the ldap to /skole/backup which is in the lvm. If you only want to have things twice (if you delete something) this setup should be fine for you.

/!\ Be aware that this backup doesn't protect you from failing harddrives.

If you want to backup your data to an external server, a tape device or another harddrive you'll have to modify the existing configuration a bit.

If you want to restore a complete folder, your best option is to use the command-line:

$ sudo rdiff-backup -r <date>  \
   /skole/backup/tjener/skole/tjener/home0/user \
   /skole/tjener/home0/user_<date>

this will leave the content from /skole/tjener/home0/user from <date> in the folder /skole/tjener/home0/user_<date>

If you want to restore a single file, then you should be able to select the file (and the version) from the web-interface, and download only that file.

Server Monitoring

Munin

Munin trend reporting system is available from https://www/munin/. It provides system status measurement graphis on a daily, weekly, monthly and yearly basis, and allow the system administrator help when looking for bottlenecks and the source of system problems.

The list of machines being monitored using munin is generated automatically based on the list of hosts reporting to sitesummary. All hosts with the package munin-node installed is registered for munin monitoring. It will normally take two days from a machine is installed until munin monitoring start, because of the order the cron jobs are executed. To speed up the process, run sitesummary-client as root on the freshly installed machine, and /etc/cron.daily/sitesummary as root on the sitesummary server (normally the main-server).

Information about the munin system is available from http://munin.projects.linpro.no/ .

Nagios

Nagios system and service monitoring is available from https://www/nagios3/. The set of machines and services being monitored is automatically generated using information collected by the sitesummary system. The machines with the profile Main-server and Thin-client-server receive full monitoring, while workstations and thin clients receive simple monitoring. To enable full monitoring on a workstation, install the nagios-nrpe-server package on the workstation.

The username is nagiosadmin and the password is undefined, you must set your own password before you can login and use nagios. For security reasons, avoid using the same password as root. To change the password you can run the following command as root:

htpasswd /etc/nagios3/htpasswd.users nagiosadmin

By default Nagios does not send email. This can be changed by replacing notify-by-nothing with host-notify-by-email and notify-by-email in the file /etc/nagios3/sitesummary-template-contacts.cfg.

The Nagios configuration file used is /etc/nagios3/sitesummary.cfg. The sitesummary cron job generate /var/lib/sitesummary/nagios-generated.cfg with the list of hosts and services to monitor.

Extra nagios checks can be put in the file /var/lib/sitesummary/nagios-generated.cfg.post to get them included in the generated file.

Information about the nagios system is available from http://www.nagios.org/ or in the nagios3-doc package.

Sitesummary

Sitesummary is used to collect information from each computer and submit it to the central server. The information collected is available in /var/lib/sitesummary/entries/. Scripts in /usr/lib/sitesummary/ are available to generate reports.

A simple report from sitesummary without any details is available from https://www/sitesummary/.

Some documentation on sitesummary is available from http://wiki.debian.org/DebianEdu/HowTo/SiteSummary

More information about Debian Edu customisations

More information about Debian Edu customisations useful for system administrators can be found in the Administration Howto chapter.

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