Network and Server Statistics Using Cacti

Network and Server Statistics Using Cacti
Network Management &
Monitoring
Network and Server Statistics
Using Cacti
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Introduction
Network Monitoring Tools
Availability
Reliability
Performance
Cacti monitors the performance and
usage of devices.
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
Cacti: Uses RRDtool, PHP and stores
data in MySQL. It supports the use
of SNMP and graphics with MRTG.
“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.”
General Description
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.
Advantages
You can measure Availability, Load, Errors and more all
with history.
– Cacti con view 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 cont.
Data Collection
– Supports SNMP including the use of php-snmp or net-snmp
– Data sources can be updated via SNMP or by defining scripts to
capture required data.
– An optional component, cactid, implements SNMP routines in C with
multi-threading. Critical for very large installations.
Templates
– You can create templates to reutilize graphics definitions, data and
device sources
Cacti Plugin Architecture
– Extends Cacti functionality. Many, many plugins are available.
User Management
– You can manage users locally or via LDAP and you can assign
granular levels of authorization by user or groups of users.
Disadvantages
•  Configuration of Interfaces is Tedious
•  Configuration of Plugin Architecture is non-trivial
•  Upgrading versions con be complex
Advice:
For continuous use or large installations it is likely that
you will be using scripts and tools to automate the
configuration of Cacti.
Steps to add and monitor devices
Before we install Cacti we demonstrate how to use
the interface to add and monitor some devices…
Adding a Device
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.
Add Devices: 2
Add Devices: 3
•  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: 4
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?
Create Graphics
•  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: 2
Create Graphics: 3
Create Graphics: 4
You’ll see this screen later when you are creating graphics for hosts vs. routers
View the Graphics
•  Place the new device in its proper location
in your tree hierarchy.
•  Building your display hierarchy is your
decision. It might make sense to try
drawing this out on paper first.
– Under Management  Graph Trees
select the Default Tree hierarchy (or,
create one of your own).
Graphics Tree
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 with 2 Devices
•  Our graphics tree just after the first two devices were added.
•  So far, no graphics are displayed – the first graphics 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.
Initial Graphs
Over time you’ll see tendencies
Next Steps
•  You can extend cacti by installing the Cacti Plugin
Architecture:
http://cactiusers.org/wiki/PluginArchitectureInstall
•  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
Conclusions
•  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 discover new devices quickly.
•  It is not easy to do a rediscover of devices.
•  To add lots of devices requires lots of time and effort.
Software such as Netdot, Netdisco, IPPlan, TIPP can
help – as well as local scripts that update the Cacti backend MySQL database directly.
References
•  Cacti Web Site:
http://www.cacti.net/
•  Cacti Discussion Group:
http://forums.cacti.net/
•  Cacti Users – Plugin Architecture Home
http://cactiusers.org/
•  Instructions to Install Cacti from Source
and configure the thold and settings
plugins are available on the class wiki
Cacti Demonstration
Before we install Cacti we are going to do a live
demonstration of how to use the Cacti interface
to add and monitor a few devices.
Cacti Installation and
Configuration
Exercises
Your Mission...
–  Install Cacti
–  Create device entry for your local router
–  Create device entries for your local servers
–  Create graphs for each item
–  Place PCs, Routers, Switches in a tree hierarchy of
your design.
If you have time…
–  Create device entries for any additional network
equipment in the classroom. Use SNMP for all items.
Use the Network Diagram on the class wiki as a reference.
Installation: Ubuntu Server 10.04
– Available in RPM form and packages for
Gentoo, Red Hat, Fedora, SuSE, FreeBSD,
etc.
– It is necessary to install cactid separately if
you wish to use this for larger installations.
This is the cacti-spine package in Ubuntu.
– In Ubuntu/Debian… (we’d do this on our
local machines:)
# apt-get install cacti
Installation: 2
We may have already done this for you. If so, you can use these
slides for informational purposes. Skip to the Cacti Web
installation steps to continue…
Use the workshop password for your sysadm user
Installation: 3
Again, use the workshop password
Installation: 4
Informational message. Is not normally an issue.
Installation: 5
We are using Apache2. Be sure this is chosen
then highlight <Ok> and press <ENTER> to continue.
Installation: 6
Choose <Yes>
Installation: 7
Use our workshop password.
Do no use a different password. You can break later
exercises.
Installation: 8
Again, use the workshop password.
Installation: 9
Finally, one last time, use the workshop password.
Cacti: Installation - Web
Now use a web browser and open the
following address:
http://pcN.ws.nsrc.org/cacti
You will see the following...
Cacti: Installation - Web
Press “Next >>”
Cacti: Installation - Web
Choose “New Install” and press “Next >>”
again.
Cacti: Installation - Web
Your screen should
look like this. If it does
not ask your instructor
for help.
Press “Finish”
Note!
Be sure that “RRDTool
1.3.x” (or higher) is chosen
and not “1.0.x”.
Cacti: First Time Login
First time login use:
User Name: admin
Password: admin
Cacti: Change Default Password
Now you must change the admin
password. Please use the workshop
password.
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