Observium is a Free Network Observation and Monitoring System (NOMS) which collects data from devices using SNMP and presents it via a (super-shiny) web interface. It can also be described as a big shitpile of php scripts full of vulnerabilities that you should never expose on the internet. By the way, if you know who I shall contact to drop my vulns, please email me.

Anyway, the recommended distribution to run this is Debian/Ubuntu/RHEL/CentOS, and I'm using Alpine Linux as hosts in my hypervisor, because it doesn't have systemd is simple, lightweight, secure, and a breeze to maintain.

There is not much things that differ from a Debian installation, just enough to be annoying:

• alpine uses mariadb instead of mysql (likely because Oracle has spend the last 10 years buying and killing open-source projects) ;
• no fancy prompt à la Debian when you install your DBMS, you have to initialize it with a command: /usr/bin/mysql_install_db --user=mysql.
• ${APACHE_LOG_DIR} must be replaced with /var/log/apache2/ in apache2's configuration file ;
• there is no site-enable folder in /etc/apache2/, you have to put the VirtualHost file in /etc/apache2/conf.d folder instead ;
• you have to enable the mod_rewrite module from apache2 in /etc/apache2/httpd.conf ;
• Packages have different names, and some of their paths must be changed in your config.php file, like changing /usr/bin/fping{,6} to /usr/sbin/fping{,6} and /usr/bin/mtr to /use/sbin/mtr.

Here is an excerpt of my .ash_history from my installation process:

apk -U upgrade
apk add subversion rddtool mtr imagemagick graphviz fping python nmap
apk add apache2 mysql mysql-client php-mysqli php-json php-pear php-mcrypt php-ctype
apk add net-snmp
mkdir -p /opt/observium && cd /opt
svn co http://svn.observium.org/svn/observium/trunk observium
cp config.php.default config.php
vim config.php  # don't forget to change the paths of the aforementioned tools
/usr/bin/mysql_install_db --user=mysql
rc-service mariadb start
rc-update add mariadb default                      
/usr/bin/mysqladmin -u root password <mysql root password>
mysql -u root -p
mysql> CREATE DATABASE observium DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
mysql> GRANT ALL PRIVILEGES ON observium.* TO 'observium'@'localhost'
    -> IDENTIFIED BY '<observium db password>';
^d
./discovery.php -u
cat<<EOF>/etc/apache2/conf.d/observium.conf
<VirtualHost *:80>
    DocumentRoot /opt/observium/html
    <FilesMatch \.php$>
      SetHandler application/x-httpd-php
    </FilesMatch>
    <Directory />
            Options FollowSymLinks
            AllowOverride None
    </Directory>
    <Directory /opt/observium/html/>
            DirectoryIndex index.php
            Options Indexes FollowSymLinks MultiViews
            AllowOverride All
            Require all granted
    </Directory>
    ErrorLog  /var/log/apache2/error.log  
    LogLevel warn
    CustomLog  /var/log/apache2/access.log combined
    ServerSignature On
</VirtualHost>
EOF
vim /etc/apache2/httpd.conf  # enable mod_rewrite
rc-update add apache2
rc-service apache2 restart

Also, since Alpine doesn't package python-mysqldb, you'll have to change the /opt/observium/poller-wrapper.py 2 command in your crontab to /opt/observium/poller.php -h all. You'll lose threading for the poller, but since I don't have many machines, I don't care.

That's it, you can now open your web browser to start using your Observium instance.