The Linux monitoring systems are often
used to follow system resources, such as CPU load, the amount of free RAM,
network traffic statics or memory consumption. Which are ones from the most
important tasks for every administrators. Furthermore, those tools notify the
network administrator (via email, SMS or other alarms) when something
interrupts or goes down which makes their life easier.
From those monitoring tools we will
list the 7 most important in this article which will be described and
identified by giving their features and mentioning their current version.
Nagios:
One from the most known, open source, powerful
monitoring systems nowadays is Nagios. It enables organizations to identify and
resolve IT infrastructure problems before affecting critical business
processes.
Nagios is licensed under GNU General
Public License which gives you permission to copy, broadcast and/or change it
under certain conditions obviously. For more details, you can check the license
as either as by using the LICENSE file of the Nagios distribution or by reading
the online version of license.
Concerning its features we can list
the following:
Ø Monitor network services (SMTP, POP3, HTTP,
NNTP, and PING), applications, operating systems, network protocols and system
metrics with the same tool.
Ø Detect infrastructure outages rapidly and send
e-mail, SMS or call phone notifications to the right people when a problem is
detected.
Ø Define network host hierarchy
Ø Users can easily develop their own services
due to the simple plugin design of Nagios.
Ø Ability to check the current network status,
notifications and problem history
Ø Open source software, full access to source
code, licensed under GPL.
Seriously, Nagios is one awesome IT
infrastructure monitoring tool which I strongly recommend it for every
administrator wishes to make his work easier and organized but it is good also
to use it with other monitoring tools since Nagios doesn’t show any graphs such
as the network interface.
Cacti:
Cacti is another monitoring system
licensed also under GPL but unlike Nagios, Cacti is a network graphing solution
designed to exploit the power of RRDTool in storing data and building graphs.
It enables users to view CPU load
graphs, RAM usage and other information collected from different hosts. Like
Nagios, Cacti supports SNMP that makes it possible to monitor: Linux’s, BSD’s
and windows hosts.
We can list the following features of
Cacti:
Ø Unlimited number of graph items.
Ø Graph data can be manipulated using the CDEF
math functions built in RRDTools.
Ø Support all RRDTool’s graph items including
AREA, STACK, LINE, COMMENT, VRULE, and HRULE.
Ø Data sources can be created by utilizing
RDDTool’s functions.
Ø Permissions can be specified per-graph for
each user.
But unlike Nagios, Cacti doesn’t
notify users while problems appear so it is recommended to use other flexible
tools supporting alerts.
Centreon:
Centreon is our third type of free
monitoring systems. Mostly called CES referencing to the Centreon Enterprise
Server, is the choice of some world’s largest company. It lets company
supervise all their infrastructure and applications comprising their information
system.
Centreon has many advantages, we can
list the following:
Ø Enable to monitor the user’s servers, active
elements and applications.
Ø Real-time operating and component management
console.
Ø Ability to maintain and support the whole
platform using the publisher solution.
Ø Unlimited number of uses and extensions via
open software mechanisms.
Ø Currently there are 4 different solutions
available to suit different organizations with evolving business needs.
Ø The CES Standard is the only open and
unlimited trial version. Unless it has a free access, a powerful
industry-standard monitoring solution is offered.
Ø CES Essentials is CES Standards including
access to new software products and services such as Platinum level supports
and various software extensions which allow users to automate the daily tasks
of administration and monitoring.
Ø CES Advanced is CES Essentials adding also the
Centreon’s complementary plugin pack and different templates comprising
databases, applications and infrastructure services.
Ø The last one is CES Complete which is the mix
of all the centreon software products and modules, including BI, BAM and Map.
It is also delivered with Platinum level support.
Zabbix :
Zabbix is our fourth free monitoring
system which is licensed as Nagios and Cacti under GPL and it is written in
PHP. We can say that Zabbix is the mix of Nagios and Cacti functions: it is
characterized by its simple way of monitoring data with graphs and its alerts
sending to user in case of any problem.
Personally, I like the way how Zabbix
can check and make report about every authorized or not change happen at one of
the user’s servers. This free monitoring
tool, can from remote hosts where Zabbix is used. It offers different types of
graphs such as network statistics, CPU load and others.
It is a little bit complicate for
beginners and some additional time to be familiar with this monitoring system
is recommended.
Zabbix as I mentioned offers the
functions of Nagios and Cacti at same time, we can list the following features
of this tool:
Ø It is fully open source, free for commercial
and non-commercial use.
Ø It enables users to easily monitor their
servers, network devices and applications, collecting appropriate statistics
and performance data.
Ø It is designed to scale from small
environments with a few devices to large ones with thousands of monitored
devices.
Ø Like Nagios, it can send notification messages
via e-mail, SMS for each notable event.
OpenNMS:
OpenNMS is another free network
monitoring system and it is the world’s first enterprise grade monitoring tool
which can be used a big number of unlimited devices. It enables users to
discover and monitor services or nodes automatically in their network.
OpenNMS has many advantages make it a
very beneficial free network monitoring tool when we can list the following:
Ø Automatic Service Discovery and Provisioning
Ø Performance Data Collection Protocols (such as
HTTP, JDBC, JMX, SNMP, XML etc)
Ø Multi-Resource Performance Reports
Ø Best Practical Solutions RT (Request Tracker)
Ø Import of nodes, interfaces, and services from
external provisioning system
Ø Performance Data Export via simple XML Schema
Ø Possibility to send e-mail or SMS
notifications to the administrators
Icinga:
Icinga is another enterprise grade
free monitoring system which enables users to follow network and its resources
and also notifies them when any problem appear. This tool can monitor as either
as complex or large environments across various locations.
Some of its various features include:
Ø Its capability to monitor different network
services (SMTP, POP3, HTTP, NNTP, PING…)
Ø Also monitor host resources (CPU load, disk
usage…)
Ø It allows users to easily develop their own
services checks due to its simple plugin design.
Ø It has support for monitoring redundant
monitoring hosts.
Ø It notifies users when service or host
problems occur and when they also get resolved.
MRTG:
MRTG (Multi Router Traffic Grapher) is
our last type of free monitoring system. It is simpler than Nagios, Cacti and
Zabbix which can be more beneficial to use it with small projects. Mostly, it
is used for monitoring network interfaces, CPU, memory and network interfaces
statistics.
Regarding its features, we can list
the following:
Ø It works on most UNIX platforms and Windows
NT.
Ø It is written with Perl and delivered with
full source.
Ø No need to install any external SNMP package
since MRTG uses a highly portable SNMP implementation written fully in Perl.
Ø It creates visual representations of the
traffic seen during the last week, month and year.
Ø It is possible to monitor 200 or more network
links from any halfway decent UNIX box.
Ø It is also possible to monitor any SNMP and to
assemble to data sources in one graph.
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