pov-check-health

This is a "poor man's Nagios": a cron script that runs once an hour to perform some basic system health checks.

Quick start:

sudo add-apt-repository ppa:pov/ppa
sudo apt-get update
sudo apt-get install pov-check-health

The checks are configured in /etc/pov/check-health, which is actually a shell file that is sourced from the cron script. If this file is missing, check-health does nothing.

You can generate a skeleton config file automatically with

check-health -g > /etc/pov/check-health

Example configuration file:

# Check that processes are running
checkproc apache2
checkproc cron
checkproc sshd
checkproc_pgrep tracd
checkproc_pgrep_full '/usr/bin/java -jar /usr/share/jenkins/jenkins.war'

# Check for daemons with known bugs and restart them automatically
checkproc atop || service atop restart

# Check for stale aspell processes (more than 2)
checktoomanyproc aspell 2

# Check for stale pidfiles
checkpidfiles /var/run/*.pid /var/run/*/*.pid

# Check free disk space
checkfs /    200M
checkfs /var 200M

# Check free inodes
checkinodes /
checkinodes /var

# Check free memory
checkram 100M

# Check excessive swap usage
checkswap 2G

# Check mail queue
checkmailq 100

# Check if /etc/aliases is up to date
checkaliases

The checks run with root privileges. Any failures are reported via cron, so make sure email delivery works and root is aliased to a working email address via /etc/aliases.

You can also run the checks manually by running check-health and see the report on the console. Run check-health -v for more verbosity. Run check-health -f filename to use a different config file (useful to test it before the cron script takes over). Run check-health -h for a brief usage notice:

Usage: check-health [-h] [-v] [-f configfile] [-g]

Available checks

These are documented in the manual page (see check-health.rst in the source tree or man check-health if you've have the package installed).

Additional tools

check-web-health

This is the same script as check-health, only it uses a different config file (/etc/pov/check-web-health), and the -g generation produces checkweb checks for websites configured in /etc/apache2/sites-enabled.

Also, the default cron configuration runs the website checks four times an hour instead of once an hour.

check-ssl-certs

This is the same script as check-ssl-certs, only it uses a different config file (/etc/pov/check-ssl-certs).

The default cron configuration runs the SSL certificate expiration checks once a day.

check-virtualenvs

Background: virtualenv is a solution for Python application sandboxing, so that different applications can use different sets of Python libraries without encountering conflicts due to incompatible versions. It works by creating directory trees that contain copies of the Python executable in addition to symlinks to the Python standard library. When you upgrade the system Python executable, you end up with stale copies of the old versions in all your virtualenvs. Sometimes this simply means you don't get the latest bugfixes. Sometimes this breaks your virtualenvs completely.

The check-virtualenvs script finds all virtualenvs on your system and compares their copies of the Python executable with the system version. It relies on mlocate (or an equivalent such as slocate) for finding the virtualenvs.

It is not yet integrated with cron.