Xymon - Introduction to Xymon
Xymon is a tool for monitoring the health of your networked servers and the
applications running on them. It provides a simple, intuitive way of checking
the health of your systems from a web browser, and can also alert you to any
problems that arise through alarms sent as e-mail, SMS messages, via a pager
or by other means.
Xymon is Open Source software, licensed under the GNU GPL. This means that you
are free to use Xymon as much as you like, and you are free to re-distribute
it and change it to suit your specific needs. However, if you change it then
you must make your changes available to others on the same terms that you
received Xymon originally. See the file COPYING in the Xymon source-archive
Xymon was called "Hobbit" until November 2008, when it was renamed to
Xymon. This was done because the name "Hobbit" is trademarked.
Xymon initially began life as an enhancement to Big Brother called
"bbgen". Over a period of 5 years, Xymon has evolved from a small
add-on to a full-fledged monitoring system with capabilities far exceeding
what was in the original Big Brother package. Xymon does still maintain some
compatibility with Big Brother, so it is possible to migrate from Big Brother
to Xymon without too much trouble.
Migrating to Xymon will give you a significant performance boost, and provide
you with much more advanced monitoring. The Xymon tools are designed for
installations that need to monitor a large number of hosts, with very little
overhead on the monitoring server. Monitoring of thousands of hosts with a
single Xymon server is possible - it was developed to handle just this task.
These are some of the core features in Xymon:
- Monitoring of hosts and networks
- Xymon collects information about your systems in two ways: From querying
network services (Web, LDAP, DNS, Mail etc.), or from scripts that run
either on the Xymon server or on the systems you monitor. The Xymon
package includes a Xymon client which you can install on the servers you
monitor; it collects data about the CPU-load, disk- and
memory-utilization, log files, network ports in use, file- and
directory-information and more. All of the information is stored inside
Xymon, and you can define conditions that result in alerts, e.g. if a
network service stops responding, or a disk fills up.
- Centralized configuration
- All configuration of Xymon is done on the Xymon server. Even when
monitoring hundreds or thousands of hosts, you can control their
configuration centrally on the Xymon server - so there is no need for you
to login to a system just to change e.g. which processes are monitored.
- Works on all major platforms
- The Xymon server works on all Unix-like systems, including Linux, Solaris,
FreeBSD, AIX, HP-UX and others. The Xymon client supports all major Unix
platforms, and there are other Open Source projects - e.g. BBWin, see
http://bbwin.sourceforge.net/ - providing support for Microsoft Windows
- A simple, intuitive web-based front-end
- "Green is good, red is bad". Using the Xymon web pages is as
simple as that. The hosts you monitor can be grouped together in a way
that makes sense in your organisation and presented in a tree-structure.
The web pages use many techniques to convey information about the
monitored systems, e.g. different icons can be used for recently changed
statuses; links to sub-pages can be listed in multiple columns; different
icons can be used for dial-up-tests or reverse-tests; selected columns can
be dropped or unconditionally included on the web pages to eliminate
unwanted information, or always include certain information; user-friendly
names can be shown for hosts regardless of their true hostname. You can
also have automatic links to on-line documentation, so information about
your critical systems is just a click away.
- Integrated trend analysis, historical data and SLA reporting
- Xymon stores trend- and availability-information about everything it
monitors. So if you need to look at how your systems behave over time,
Xymon has all of the information you need: Whether it is response times of
your web pages during peak hours, the CPU utilization over the past 4
weeks, or what the availability of a site was compared to the SLA - it's
all there inside Xymon. All measurements are tracked and made available in
When you need to drill down into events that have occurred, Xymon provides a
powerful tool for viewing the event history for each status log, with
overviews of when problems have occurred during the past and easy-to-use
zoom-in on the event.
For SLA reporting, You can configure planned downtime, agreed service
availability level, service availability time and have Xymon generate
availability reports directly showing the actual availability measured
against the agreed SLA. Such reports of service availability can be
generated on-the-fly, or pre-generated e.g. for monthly reporting.
- Role-based views
- You can have multiple different views of the same hosts for different
parts of the organisation, e.g. one view for the hardware group, and
another view for the webmasters - all of them fed by the same test tools.
If you have a dedicated Network Operations Center, you can configure
precisely which alerts will appear on their monitors - e.g. a simple
anomaly in the system log file need not trigger a call to 3rd-level
support at 2 AM, but if the on-line shop goes down you do want someone to
respond immediately. So you put the web-check for the on-line shop on the
NOC monitor page, and leave out the log-file check.
- Also for the techies
- The Xymon user-interface is simple, but engineers will also find lots of
relevant information. E.g. the data that clients report to Xymon contain
the raw output from a number of system commands. That information is
available directly in Xymon, so an administrator no longer needs to login
to a server to get an overview of how it is behaving - the very commands
they would normally run have already been performed, and the results are
on-line in Xymon.
- Easy to adapt to your needs
- Xymon includes a lot of tests in the core package, but there will always
be something specific to your setup that you would like to watch. Xymon
allows you to write test scripts in your favorite scripting language and
have the results show up as regular status columns in Xymon. You can
trigger alerts from these, and even track trends in graphs just by a
simple configuration setting.
- Real network service tests
- The network test tool knows how to test most commonly used protocols,
including HTTP, SMTP (e-mail), DNS, LDAP (directory services), and many
more. When checking websites, it is possible to not only check that the
web server is responding, but also that the response looks correct by
matching the response against a pre-defined pattern or a check-sum. So you
can test that a network service is really working and supplying the data
you expect - not just that the service is running.
Protocols that use SSL encryption such as https web sites are fully
supported, and while checking such services the network tester will
automatically run a check of the validity of the SSL server certificate,
and warn about certificates that are about to expire.
- Highly configurable alerts
- You want to know when something breaks. But you don't want to get flooded
with alerts all the time. Xymon lets you define several criteria for when
to send out an alert, so you only get alerts when there is really
something that needs your attention right away. While you are handling an
incident, you can tell Xymon about it so it stops sending more alerts, and
so that everyone else can check with Xymon and know that the problem is
being taken care of.
- Combined super-tests and test inter-dependencies
- If a single test is not enough, combination tests can be defined that
combine the result of several tests to a single status-report. So if you
need to monitor that at least 3 out of 5 servers are running at any time,
Xymon can do that for you and generate the necessary availability report.
Tests can also be configured to depend on each other, so that when a
critical router goes down you will get alerts only for the router - and
not from the 200 hosts behind the router.
All of the Xymon server tools run under an unprivileged user account. A single
program - the xymonping(1)
network connectivity tester - must be
installed setuid-root, but has been written so that it drops all root
privileges immediately after performing the operation that requires root
It is recommended that you setup a dedicated account for Xymon.
Communications between the Xymon server and Xymon clients use the Big Brother
TCP port 1984. If the Xymon server is located behind a firewall, it must allow
for inbound connections to the Xymon server on tcp port 1984. Normally, Xymon
clients - i.e. the servers you are monitoring - must be permitted to connect
to the Xymon server on this port. However, if that is not possible due to
firewall policies, then Xymon includes the xymonfetch(8)
tools to allows for a pull-style way of collecting data,
where it is the Xymon server that initiates connections to the clients.
The Xymon web pages are dynamically generated through CGI programs.
Access to the Xymon web pages is controlled through your web server access
controls, e.g. you can require a login through some form of HTTP
A site running this software can be seen at http://www.xymon.com/
You will need a Unix-like system (Linux, Solaris, HP-UX, AIX, FreeBSD, Mac OS X
or similar) with a web server installed. You will also need a C compiler and
some additional libraries, but many systems come with the required development
tools and libraries pre-installed. The required libraries are:
This library is used to store and present trend-data. It is
This library is used for advanced pattern-matching of text
strings in configuration files. This library is required.
This library is used for communication with SSL-enabled network
services. Although optional, it is recommended that you install this for Xymon
since many network tests do use SSL.
This library is used for testing LDAP servers. Use of this is
For more detailed information about Xymon system requirements and how to install
Xymon, refer to the on-line documentation "Installing Xymon"
available from the Xymon web server (via the "Help" menu), or from
the "docs/install.html" file in the Xymon source archive.
firstname.lastname@example.org is an open mailing list for discussions about Xymon. If you
would like to participate, send an e-mail to email@example.com
to join the list, or visit http://lists.xymon.com/mailman/listinfo/xymon .
An archive of the mailing list is available at http://lists.xymon.com/archive/
If you just want to be notified of new releases of Xymon, please subscribe to
the xymon-announce mailing list. This is a moderated list, used only for
announcing new Xymon releases. To be added to the list, send an e-mail to
These tools implement the core functionality of the Xymon server:
is the core daemon that collects all reports about the status
of your hosts. It uses a number of helper modules to implement certain tasks
such as updating log files and sending out alerts: xymond_client,
xymond_history, xymond_alert and xymond_rrd. There is also a xymond_filestore
module for compatibility with Big Brother.
Implements the communication between the Xymon daemon
and the other Xymon server modules.
Stores historical data about the things that Xymon
Stores trend data, which is used to generate graphs of the
data monitored by Xymon.
handles alerts. When a status changes to a critical
state, this module decides if an alert should be sent out, and to whom.
handles data collected by the Xymon clients, analyzes
the data and feeds back several status updates to Xymon to build the view of
the client status.
stores historical client data when something breaks.
E.g. when a web page stops responding xymond_hostdata will save the latest
client data, so that you can use this to view a snapshot of how the system
state was just prior to it failing.
These tools are used on servers that execute tests of network services.
performs network connectivity (ping) tests.
runs the network service tests.
is an extension script for re-doing failed network
tests with a higher frequency than the normal network tests. This allows Xymon
to pick up the recovery of a network service as soon as it happens, resulting
in less downtime being recorded.
These tools take care of generating and updating the various Xymon web-pages.
takes care of updating the Xymon web pages.
This CGI program generates an HTML view of a single
status log. It is used to present the Xymon status-logs.
This CGI program generates graphs of the trend-data
collected by Xymon.
When you want to combine multiple graphs into one, this
CGI lets you combine graphs so you can e.g. compare the load on all of the
nodes in your server farm.
Generates the Critical Systems view, based on the
currently critical systems and the configuration of what systems and services
you want to monitor when.
This CGI program generates a web page with the most recent
history of a particular host+service combination.
This CGI lets you view a log of events that have happened
over a period of time, for a single host or test, or for multiple systems.
This CGI program allows a user to acknowledge an alert he
received from Xymon about a host that is in a critical state. Acknowledging an
alert serves two purposes: First, it stops more alerts from being sent so the
technicians are not bothered wit more alerts, and secondly it provides
feedback to those looking at the Xymon web pages that the problem is being
is a tool for processing acknowledgments sent via
e-mail, e.g. as a response to an e-mail alert.
is a CGI program to disable or re-enable hosts or
individual tests. When disabling a host or test, you stop alarms from being
sent and also any outages do not affect the SLA calculations. So this tool is
useful when systems are being brought down for maintenance.
is a CGI program that finds a given host in the Xymon web
pages. As your Xymon installation grows, it can become difficult to remember
exactly which page a host is on; this CGI script lets you find hosts easily.
This CGI program triggers the generation of Xymon
availability reports, using xymongen(1)
as the reporting back-end
This CGI program generates the detailed availability
report for a particular host+service combination.
is a CGI program to build the Xymon web pages in a
"snapshot" mode, showing the look of the web pages at a particular
point in time. It uses xymongen(1)
as the back-end engine.
is a CGI program reporting test results for a single
status but for several hosts. It is used to e.g. see which SSL certificates
are about to expire, across all of the Xymon web pages.
is a CGI program to present information about a host. The
information is pulled from a CSV (Comma Separated Values) file, which is
easily exported from any spreadsheet or database program.
is a utility used by the Xymon Unix client to collect
information from log files on the client. It can also monitor various other
file-related data, e.g. file meta-data or directory sizes.
Is used on Xymon clients, to automatically update the
client software with new versions. Through this tool, updates of the client
software can happen without an administrator having to logon to the server.
This tool acts as a mini Xymon server to the client. It
stores client data internally, so that the xymonfetch(8)
pick it up later and send it to the Xymon server. It is typically used on
hosts that cannot contact the Xymon server directly due to network- or
These tools are used for communications between the Xymon server and the Xymon
clients. If there are no firewalls then they are not needed, but it may be
necessary due to network or firewall issues to make use of them.
is a proxy-server that forwards Xymon messages between
clients and the Xymon server. The clients must be able to talk to the proxy,
and the proxy must be able to talk to the Xymon server.
is used when the client is not able to make outbound
connections to neither xymonproxy nor the Xymon server (typically, for clients
located in a DMZ network zone). Together with the msgcache(8)
running on the client, the Xymon server can contact the clients and pick up
is a program scheduler for Xymon. It acts as a master
program for running all of the Xymon tools on a system. On the Xymon server,
it controls running all of the server tasks. On a Xymon client, it
periodically launches the client to collect data and send them to the Xymon
is the tool used to communicate with the Xymon server. It is
used to send status reports to the Xymon server, through the custom Xymon/BB
protocol, or via HTTP. It can be used to query the state of tests on the
central Xymon server and retrieve Xymon configuration files. The server-side
used to receive messages sent via HTTP is
is a wrapper for the other Xymon tools which sets up all of
the environment variables used by Xymon tools.
is a utility for use by Xymon extension scripts. It allows
an extension script to easily pick out the hosts that are relevant to a
script, so it need not parse a huge hosts.cfg file with lots of unwanted
is a utility to dump the full hosts.cfg(5)
following any "include" statements.
is a utility to compute message digest values for use in
content checks that use digests.
is an extension script for the Xymon server, allowing you
to build complicated tests from simpler Xymon test results. E.g. you can
define a test that uses the results from testing your web server, database
server and router to have a single test showing the availability of your
enterprise web application.
is a tool to trim the Xymon history logs. It will remove
all log entries and optionally also the individual status-logs for events that
happened before a given time.
Version 1 of bbgen was released in November 2002, and optimized the web page
generation on Big Brother servers.
Version 2 of bbgen was released in April 2003, and added a tool for performing
Version 3 of bbgen was released in September 2004, and eliminated the use of
several external libraries for network tests, resulting in a significant
With version 4.0 released on March 30 2005, the project was de-coupled from Big
Brother, and the name changed to Hobbit. This version was the first full
implementation of the Hobbit server, but it still used the data collected by
Big Brother clients for monitoring host metrics.
Version 4.1 was released in July 2005 included a simple client for Unix. Log
file monitoring was not implemented.
Version 4.2 was released in July 2006, and includes a fully functional client
Version 4.3 was released in November 2010, and implemented the renaming of the
project to Xymon. This name was already introduced in 2008 with a patch
version of 4.2, but with version 4.3.0 this change of names was fully
Copyright (C) 2002-2011 Henrik Storner <firstname.lastname@example.org>
Parts of the Xymon sources are from public-domain or other freely available
sources. These are the the Red-Black tree implementation, and the MD5-, SHA1-
and RIPEMD160-implementations. Details of the license for these is in the
README file included with the Xymon sources. All other files are released
under the GNU General Public License version 2, with the additional exemption
that compiling, linking, and/or using OpenSSL is allowed. See the file COPYING
xymond(8), xymond_channel(8), xymond_history(8), xymond_rrd(8), xymond_alert(8),
xymond_client(8), xymond_hostdata(8), xymonping(1), xymonnet(1),
xymonnet-again.sh(1), xymongen(1), svcstatus.cgi(1), showgraph.cgi(1),
hostgraphs.cgi(1), criticalview.cgi(1), history.cgi(1), eventlog.cgi(1),
ack.cgi(1), xymon-mailack(8), enadis.cgi(8), findhost.cgi(1), report.cgi(1),
reportlog.cgi(1), snapshot.cgi(1), statusreport.cgi(1), csvinfo.cgi(1),
logfetch(1), clientupdate(1), msgcache(8), xymonproxy(8), xymonfetch(8),
xymonlaunch(8), xymon(1), xymoncgimsg.cgi(1), xymoncmd(1), xymongrep(1),
xymoncfg(1), xymondigest(1), combostatus(1), trimhistory(8), hosts.cfg(5),
tasks.cfg(5), xymonserver.cfg(5), alerts.cfg(5), analysis.cfg(5),