Cacti Network Monitoring Networking Tools

Network Monitoring & Management
Using Cacti
Network Startup Resource Center
www.nsrc.org
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Network Monitoring Tools
Availability
Reliability
Performance
Cacti monitors the performance and usage of
devices.
Introduction

Cacti: Uses RRDtool, PHP and stores
data in MySQL. It supports the use
of SNMP and graphics with RRDtool.
“Cacti is a complete frontend to RRDTool, it stores all of the necessary
information to create graphs and populate them with data in a MySQL
database. The frontend is completely PHP driven. Along with being able to
maintain Graphs, Data Sources, and Round Robin Archives in a database,
cacti handles the data gathering. There is also SNMP support for those
used to creating traffic graphs with MRTG.”
Introduction

• A tool to monitor, store and present
network and system/server statistics
• Designed around RRDTool with a special
emphasis on the graphical interface
• Almost all of Cacti's functionality can be
configured via the Web.
• You can find Cacti here:
http://www.cacti.net/
Introduction

• Round Robin Database for time series data storage
• Command line based
• From the author of MRTG
• Made to be faster and more flexible
• Includes CGI and Graphing tools, plus APIs
• Solves the Historical Trends and Simple Interface problems as
well as storage issues
Find RRDtool here: http://oss.oetiker.ch/rrdtool/
Getting RRDtool

1. Cacti is written as a group of PHP scripts.
2. The key script is “poller.php”, which runs every 5 minutes
(by default). It resides in /usr/share/cacti/site.
3. To work poller.php needs to be in /etc/cron.d/cacti like this:
MAILTO=root
*/5 * * * * www-data php /usr/share/cacti/site/poller.php >/dev/null 2>/var/log/cacti/poller-error.log
4. Cacti uses RRDtool to create graphs for each device and
data that is collected about that device. You can adjust all
of this from within the Cacti web interface.
5. The RRD files are located in /var/lib/cacti/rra when cacti is
installed from packages.
General Description

You can measure Availability, Load, Errors and more all
with history.
– Cacti can display your router and switch interfaces and their traffic,
including all error traffic as well.
– Cacti can measure drive capacity, CPU load (network h/w and servers) and
much more. It can react to conditions and send notifications based on
specified ranges.
Graphics
– Allows you to use all the functionality of rrdgraph to define graphics and
automate how they are displayed.
– Allows you to organize information in hierarchical tree structures.
Data Sources
– Permits you to utilize all the functions of rrdcreate and rrdupdate including
defining several sources of information for each RRD file.
Advantages

Data Collection
– Supports SNMP including the use of php-snmp or net-snmp
– Update data sources via SNMP or define scripts to capture required data
– cactid implements SNMP routines in C with multi-threading
Templates
– Create templates to reutilize graphics definitions, data and device sources
Cacti Plugin Architecture
– Extends Cacti functionality. Many, many plugins are available. Part of the
default Cacti installation in Ubuntu version 12 and above.
User Management
– Manage users locally or via LDAP
– Assign granular levels of authorization by user or groups of users.
Advantages (continued)

• Configuring Interfaces via the web interface is tedious
• Use provided command-line scripts instead
• Upgrading versions difficult if installed from source.
Advice:
For continuous use or large installations it is likely that
you will be using scripts and tools to automate the
configuration of Cacti.
Disadvantages

PART II
Before we install Cacti we demonstrate how to use the
interface to add and monitor some devices…
Steps to Add and Monitor Devices

Management -> Devices -> Add
Specify device attributes
– We’ll add an entry for our gateway router, gw.ws.nsrc.org*
*Actual device name may be different.
Adding a Device via the Web Interface

• Host Template: ucd/net SNMP Host is recommended for
servers to include disk definitions.
• Choose SNMP version 2 for this workshop.
• For “Downed Device Detection” we recommend either
using Ping and SNMP, or just Ping.
• Use “NetManage” for the “SNMP Community” string.
SNMP access is a security issue:
- Version 2 is not encrypted
- Watch out for globally readable “public” communities
- Be careful about who can access r/w communities.
- Replace “xxxxxxx” with your local public r/o string
Add Devices (3)

For a router you may see a lot of potential network
interfaces that are detected by SNMP.
Your decision is to create graphs for all of these
are not. Generally the answer is, “Yes” – Why?
Add Devices (4)

• Chose the “Create graphs for this host”
• Under Graph Templates generally check the
top box that chooses all the available graphs to
be displayed.
• Press Create.
• You can change the default colors, but the
predefined definitions generally work well.
Create Graphics

You’ll see this screen later when you are creating graphics for hosts vs. routers
Create Graphics (4)

• Place the new device in its proper location in
your tree hierarchy.
• Building your display hierarchy is your decision.
Try drawing this out on paper first.
–Under Management  Graph Trees
select the Default Tree hierarchy (or, create
one of your own).
View the Graphics

First, press “Add” if you want a new graphing tree:
Second, name your tree, choose the sorting order (the author likes
Natural Sorting and press “create”:
Graphics Tree

Third, add devices to your new tree:
Once you click “Add” you can add “Headers” (separators), graphs or hosts.
Now we'll add Hosts to our newly created graph tree:
Graphics Tree

• Our graphics tree just after the first two devices were added.
• So far, graphics are empty – the first data can
take up to 5 minutes to display.
• Cacti graphs are stored on disk and updated using RRDTool
via the poller.php script, which, by default, is run every five
minutes using cron.
Graphics Tree with Two Devices

• There are a number of popular Cacti plugins, such as:
- Settings
- thold
- PHP Weathermap
• A good place to start is http://cactiusers.net/ and Google.
• To send email to RT from Cacti via rt-mailgate you can
use the Cacti “settings” plugin:
http://docs.cacti.net/plugin:settings
• Automate device and graph creation using available
command-line scripts in /usr/share/cacti/cli, such as:
- add_devices.php
- add_graphs.php
- add_tree.php
Next Steps

• Cacti is very flexible due to its use of templates.
• Once you understand the concepts behind RRDTool,
then how Cacti works should be (more or less) intuitive.
• The visualization hierarchy of devices helps to organize
and locate new devices quickly.
• It is not easy to do a rediscover of devices.
• To add lots of devices requires automation. Software
such as Netdot, Netdisco, IPPlan, TIPP can help – as
well as local scripts that update the Cacti back-end
MySQL database directly.
Conclusions

• Cacti Web Site:
http://www.cacti.net/
• Plugin Documentation
http://docs.cacti.net/plugins
• Cacti Discussion Group:
http://forums.cacti.net/
• Cacti Users – Plugin Architecture Home
http://cactiusers.org/
References

Cacti Installation and Configuration
Workshop Labs

Cacti Network Monitoring Networking Tools

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