collectd is a UNIX-daemon that collects, transfers and stores performance data of computers and network equipment. The acquired data is meant to help system administrators maintain an overview over available resources to detect existing or looming bottlenecks (source).
collectd uses a modular design: the daemon itself only implements infrastructure for filtering and relaying data as well as auxiliary functions and requires very few resources.
Data acquisition and storage is handled by plugins in the form of shared objects. Data acquisition plug-ins, called "read plugins" in collectd's documentation so called "write plug-ins" offer the possibility to store the collected data on disk using RRD- or CSV-files, or to send data over the network to a remote instance of the daemon.
collectd for data gathering and
rrdtool for visualization.
There are packages in package repositories for Arch Linux and Ubuntu.
# arch yaourt -S collectd rrdtool # ubuntu sudo apt-get install collectd rrdtool
The configuration lie in /etc/collectd.conf.
For each plugin, there is a
LoadPlugin line in the configuration. Almost all of those lines are commented out in order to keep the default configuration lean. By default the following plugins are enabled: CPU, Interface, Load, and Memory.
Simple config file
# egrep -v '^$|^#' /etc/collectd/collectd.conf FQDNLookup true LoadPlugin syslog <Plugin syslog> LogLevel info </Plugin> LoadPlugin cpu LoadPlugin df LoadPlugin interface LoadPlugin load LoadPlugin memory LoadPlugin processes LoadPlugin rrdtool LoadPlugin swap LoadPlugin users <Plugin rrdtool> DataDir "/var/lib/collectd/rrd" </Plugin> <Plugin df> Device "/dev/sda1" MountPoint "/" FSType "ext4" </Plugin> Include "/etc/collectd/filters.conf" Include "/etc/collectd/thresholds.conf"
If you're done configuring, you need to (re-)start the daemon.
# start in arch sudo systemctl start collectd.service # restart in arch sudo systemctl restart collectd.service # enable in arch sudo systemctl restart collectd.service # start in ubuntu sudo service collectd start # restart in ubuntu sudo service collectd restart
There are many options to present data from collectd. You can use front-ends (collectd-web, graphite, visage) or generate png files with rrdtool and include in html file which is accessible from outside.
First option is to use front-end. I'm going to show Collectd-Web.
# download git clone git://github.com/httpdss/collectd-web.git # check dependency cd collectd-web ./check_deps.sh # make sure collectd looks under the correct location # cat /etc/collectd/collection.conf datadir: "/var/lib/collectd/rrd/" libdir: "/usr/lib/collectd/"
After that you should copy collectd-web to public directory.
sudo cp -r *.* /var/www/example.com/public/
Second option is to use rrdtool for generation png file with diagram. After generation we can use images in any html file as source for img tag.
Example of rrdtool script you can get here.
Add it to cron as usual
# sudo crontab -e */15 * * * * root /path/to/script.sh > /dev/null 2>&1
You can check your network speed with speedtest-cli.
Collectd can inform you if something is strange. For example, it can send email if CPU load is more than 80% or RAM utilization is more than 90% and so on.
First, we need activate
notify_email plugin and set recipient.
# sudo vim /etc/collectd/collectd.conf LoadPlugin "threshold" LoadPlugin notify_email <Plugin notify_email> SMTPServer "stmp.example.com" SMTPPort 25 SMTPUser "firstname.lastname@example.org" SMTPPassword "password" From "email@example.com" Subject "[collectd] %s on %s!" Recipient "firstname.lastname@example.org" </Plugin>
Second, set up threshold
# sudo vim /etc/collectd/thresholds.conf <Threshold> <Type "cpu"> Instance "user" WarningMax 85 Hits 1 </Type> </Threshold>
Last, restart collectd
# restart in arch sudo systemctl restart collectd.service # restart in ubuntu sudo service collectd restart
You can check CPU overload with cpuburn.
How to write custom plugin